Kristian Birkeland: The First Space Scientist (Astrophysics and Space Science Library)

KRISTIAN BIRKELAND ASTROPHYSICS AND SPACE SCIENCE LIBRARY VOLUME 325 V EDITORIAL BOARD Chairman W.B. BURTON, Nationa...

Author: Alv Egeland | William J. Burke

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KRISTIAN BIRKELAND

ASTROPHYSICS AND SPACE SCIENCE LIBRARY VOLUME 325 V

EDITORIAL BOARD Chairman W.B. BURTON, National Astronomy Observatory, Charlottesville, Virginia, U.S.A. ([email protected]); University of Leiden, The Netherlands ([email protected]) Executive Committe J. M. E. KUIJPERS, F Faculty of Science, Nijmegen, The Netherlands E. P. J. VAN DEN HEUVEL, Astronomical Institute, University of Amsterdam, The Netherlands H. VAN DER LAAN, Astronomical Institute, University of Utrecht, The Netherlands

MEMBERS I. APPENZELLER, Landessternwarte Heidelberg-K¨ Konigstuhl, Germany K¨ J. N. BAHCALL, The Institute for Advanced Study, Princeton, U.S.A. F. BERTOLA, Universit´ ta di Padova, t´ P Italy J. P. CASSINELLI, University of Wisconsin, Madison, U.S.A. C. J. CESSARSKY, Centre d’Etudes de Saclay, Gif-sur-Yvette Cedex, France O. ENGVOLD, Institute of Theoretical Astrophysics, University of Oslo, Norway R. MCCRAY, University of Colorado, JILA, Boulder, U.S.A. P. G. MURDIN, Institute of Astronomy Cambridge, U.K. F. PACINI, Istituto Astronomia Arcetri, Firenze, Italy V. RADHKRISHNAN, Raman Research Institute, Banglore, India K. SATO, School of Science, The University of Tokyo, Japan F. H. SHU, University of California, Berkeley, U.S.A. B. V. SOMOV, Astronomical Institute, Moscow State University, Russia R. A. SUNYAEV, Space Research Institute, Moscow, Russia Y. TAN ANAKA, Institute of Space & Astronautical Science, Kanagawa, Japan S. TREMAINE, CITA, Princeton University, U.S.A. N. O. WEISS, University of Cambridge, U.K.

KRISTIAN BIRKELAND The First Space Scientist

by

ALV EGELAND University of Oslo, Norway

and

WILLIAM J. BURKE Air Force Research Laboratory, USA

A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN-10 1-4020-3293-5 (HB) Springer Dordrecht, Berlin, Heidelberg, New York ISBN-10 1-4020-3294-3 (e-book) Springer Dordrecht, Berlin, Heidelberg, New York ISBN-13 978-1-4020-3293-6 (HB) Springer Dordrecht, Berlin, Heidelberg, New York ISBN-13 978-1-4020-3294-3 (e-book) Springer Dordrecht, Berlin, Heidelberg, New York

Published by Springer P.O. Box 17, 3300 AA Dordrecht, The Netherlands.

Printed on acid-free paper

Caption to Front Plate: Professor Kristian Birkeland with his left hand resting on an electric discharge tube of the high-voltage device used in 1896 to generate artiﬁcial auroral displays in his laboratory. Asta Nørregaard (1853–1933) painted this portrait in 1906 (100 × 83 cm). All Rights Reserved C 2005 Springer No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microﬁlming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied speciﬁcally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed in the Netherlands.

CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ix 1

Part I: Background and Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 At the 19th Century’s End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Union of Norway and Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 The Royal Frederik University in Kristiania . . . . . . . . . . . . . . . . . . . 1.3 Early Investigation of the Aurora and Geomagnetism . . . . . . . . . . . 2 A New Abel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 The Birkeland Family . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 High School and University Education . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Postgraduate Research in France, Switzerland, and Germany . . . .

11 11 11 12 13 17 17 19 22

Part II: Geomagnetic and Solar System Research . . . . . . . . . . . . . . . . 3 Aurora in a Vacuum Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Electromagnetic Wave Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Early Laboratory Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 Birkeland’s Ofﬁces and Laboratories at the University . . . . . . . . . . 3.4 Terrella as Anode Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 The Norwegian Auroral Expeditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Birkeland’s First Expeditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Arctic Expedition of 1902–1903 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 The Four Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2 Birkeland’s Main Research Contribution . . . . . . . . . . . . . . . . . 4.3 Classiﬁcation of Geomagnetic Disturbances . . . . . . . . . . . . . . . . . . . 4.3.1 Polar Elementary Storms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.2 Equatorial Perturbations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.3 Cyclo-Median Perturbations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.4 Field-Aligned Currents in Space . . . . . . . . . . . . . . . . . . . . . . . . 4.4 The Permanent Station at Haldde Mountain . . . . . . . . . . . . . . . . . . . 4.5 Controversies with the British School . . . . . . . . . . . . . . . . . . . . . . . . . 5 The Universe in a Vacuum Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Terrella as Cathode Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Sunspots and the Solar Magnetic Field . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Comet Tails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Saturn’s Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Zodiacal Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 Conﬂicts with Carl Størmer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27 27 27 28 34 36 45 45 57 61 66 70 72 73 74 75 77 80 87 87 87 90 93 94 98

vi

CONTENTS

Part III: Technology and Applied Physics . . . . . . . . . . . . . . . . . . . . . . . . 6 Fast Switches and Electromagnetic Cannons . . . . . . . . . . . . . . . . . . . . 7 In as Little as Four Years. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Plasma Torch and Nitrogen Fixation . . . . . . . . . . . . . . . . . . . . . . 7.2 Foundation of Norsk Hydro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Conﬂict with Sam Eyde . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Marcus Wallenberg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Other Technical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.1 X-Rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.2 Atomic Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.3 Rocket Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.4 Radiowave Propagation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.5 Production of Margarine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.6 Hearing Aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.7 Cod Caviar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.8 Radiation Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

101 101 109 109 115 120 123 125 126 126 128 128 129 129 130 130

Part IV: Birkeland the Man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 As Seen in His Own time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Teacher and Experimenter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 Birkeland as a Popular Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Positions and Honors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 Nominations for the Nobel Prize . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.1 Nobel Prize in Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4.2 Nobel Prize in Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Consummatus in brevi, explevit tempora multa . . . . . . . . . . . . . . . . . . 9.1 Birkeland’s Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 Marriage and Divorce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 Sojourn in Egypt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4 Death in Tokyo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5 Many Friends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 Birkeland’s Will . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

131 131 132 135 137 138 139 140 141 141 143 145 148 156 162

Part V: Birkeland’s Heritage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 From Small Acorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 Science Education in Norway . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 Inﬂuence on Solar-Terrestrial Research . . . . . . . . . . . . . . . . . . . . 11 In Memoriam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Kristian Birkeland Research Fund . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Birkeland Symposium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

165 165 166 167 175 175 176

CONTENTS 11.3 Birkeland Lecture Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4 The Norwegian 200 Kroner Banknote . . . . . . . . . . . . . . . . . . . . . Appendix 1 Birkeland’s Scientiﬁc Publications . . . . . . . . . . . . . . . . . . . . Appendix 2 Archives and Unpublished Sources . . . . . . . . . . . . . . . . . . . Olaf Devik’s Personal Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Birkeland-Eyde Industrial Museum at Notodden . . . . . . . . . . . . . Norwegian Technical Museum in Oslo . . . . . . . . . . . . . . . . . . . . . . . . . . The National Library Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Norsk Hydro Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sam Eyde Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Norwegian Storting Archives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . University of Oslo, Central Administration . . . . . . . . . . . . . . . . . . . . . . Stockholm Enskilda Banken Archives . . . . . . . . . . . . . . . . . . . . . . . . . . Norwegian Academy of Science and Letters Archive . . . . . . . . . . . . . Printed Sources from Norwegian Newspapers and Journals . . . . . . . Biographies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix 3 Patents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix 4 Letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Letter: Birkeland to Kaja Geemuyden . . . . . . . . . . . . . . . . . . . . . . . . . . Extracts from Terada’s Diary Concerning Kristian Birkeland in May–June 1917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Letter: Terada to Birkeland (written in English) . . . . . . . . . . . . . . . . . . Letter: Terada to Birkeland (written in English) . . . . . . . . . . . . . . . . . . Letter: Nagaoka to Birkeland (written in English) . . . . . . . . . . . . . . . . Letter: Terada to Birkeland (written in English) . . . . . . . . . . . . . . . . . . Letter: Nagaoka to Birkeland (written in English) . . . . . . . . . . . . . . . . Letter: Gerda Thomsen to Karl Devik . . . . . . . . . . . . . . . . . . . . . . . . . . Letter: Eriksen to Birkeland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii 176 179 181 189 189 189 190 191 191 191 192 192 192 192 192 194 195 201 201 203 205 206 207 208 209 210 213 215 219

PREFACE

This scientiﬁc biography of Kristian Birkeland (1867–1917) was written to bring the story of a Norwegian national hero to the attention of the Englishspeaking world. Birkeland’s heroic stature was established not on a ﬁeld of military battle, but in the bitter cold of the Artic wilderness as he sought to answer basic questions about how the Sun controlled northern lights and magnetic storms. He was also a father of Norsk Hydro one of Norway’s largest industries. Birkeland died before reaching the age of 50. Because Birkeland never kept a diary, documented information about his ffamily and private life is sparse. Before he died, Olaf Devik, the last of Birkeland’s close friends, gave a long interview and graciously transferred his personal archive to A.E. Birkeland’s 82 scientiﬁc papers and three book-length publications map the progress of his investigations. We are grateful for the access granted to review the contents of many different archives. We greatly beneﬁted from discussions with Professors Leiv Harang and Hannes Alfv´en as well as members of the Norsk Hydro staff. We are very grateful to Professor Naoshi Fukushima for translating and making available to us Birkelandrelated segments of Torahiko Terada’s diary. A.E. would also like to thank Espen Trondsen (University of Oslo) for computer assistance and Mrs L. Hedlund for T language advice. We also extend special thanks to the staffs at The Norwegian Technical Museum, the Alta Museum responsible for the Haldde Observatory, and to the Birkeland-Eyde Industrial Museum at Notodden for providing useful illustrations. The authors express our special thanks to Ms Louise C. Gentile of Boston College Institute for Scientiﬁc Research for proofreading and editing our manuscript. This book would have been impossible to write without the constant encouragement of our families, professional colleagues, and friends. Our gratitude extends to all who made this book possible. Alv Egeland William J. Burke W

INTRODUCTION: TEMPORA MUTANT ET NOS CUM ILLIS MUTAMUR

Our lives pass within conﬁnes that are brief in time and limited in range. Miracles of modern medicine prolong our days; modern means of communication and transportation extend our reach across the globe. Still we know limits. Personal inﬂuence is restricted in duration and locality. Yet there are people, Mozart comes to mind, whose contributions to collective human experience extend beyond their prescribed times and places. We place before readers of this book, a synopsis of the life and contributions of such a man, Olaf Kristian Bernhard Birkeland, a Professor of Physics at The Royal Frederik University in Kristiania,1 the capital of Norway, near the beginning of the 20th century. Our subtitle The First Space Scientist, places Birkeland’s life in the context of space exploration, half a century before “Sputnik” and “Apollo” entered our vocabularies. Over the course of the 20th century “space” evolved in the public consciousness from the captivating science ﬁction of Jules Verne (1828–1905) to a practical reality that touches innumerable aspects of modern living. We plan our activities around weather forecasts based on images from satellites hovering about 36,000 kilometers above the Earth’s surface. How did this transformation come about? While it represents a triumph of rocket technology, much more is involved. Scientists had to devise and miniaturize electronic devices. This required the development of new materials that could withstand and operate in the harsh radiation environments of space. Industry had to create new management and quality assurance skills to meet schedules of unprecedented complexity. Every single mechanical and electronic component has to work within exacting speciﬁcations. Once launched, repair services are not available to replace failed components on a 100 million dollar spacecraft. The extraordinarily high cost of entry to space requires national and international investments and visions of future possibilities. The critical alliances among science, government, and industry needed to understand and operate in space were simply unimaginable as the 20th century began. At the time scientists constituted a very small percentage of the total population. The vast majority of these were either associated with universities or independently wealthy. Of the former, teaching responsibilities usually outweighed 1

In 1925, Norway’s capital reverted to Oslo, its name before the devastating ﬁre in 1624. King Kristian IV of Denmark rebuilt the region and renamed the city. For 300 years, the city was called Christiania, but during the last period was spelled Kristiania, as used here.

2

INTRODUCTION

research opportunities. Still progress was made. As the 19th century concluded, practical implications of a newly discovered unity underlying electrical and magnetic phenomena were being grasped. Understanding, controlling, and utilizing the new world of electromagnetism challenged the contemporary imagination. Scientists distinguish between phenomena in laboratory experiments and in nature. Laboratory investigators control experimental environments exactingly to test theoretical understanding and to identify new interactions. At the other extreme, astrophysicists can only measure the effects of natural forces that lie light years beyond human control and try to interpret observations in the light of known physical laws. Much of Birkeland’s story concerns hard won observations and bold interpretations of the natural interactions between the Sun and the Earth’s magnetic ﬁeld that produce auroral displays and geomagnetic storms. Birkeland distinguished himself from contemporary investigators though laboratory simulations of natural electrical phenomena. Far ahead of his time, Birkeland’s prophetic concepts about the electric particles and currents controlling the physics of space passed into decades of eclipse before reemerging in the 1970s. Throughout the years of eclipse, Birkeland’s reputation remained strong in Scandinavia, although heated debates raged concerning the validity of his speculations about space. Even in principle, no resolution could be found before spacecraft probed altitudes above 100 kilometers. Birkeland’s reputation survived and ﬂourished because he was the ﬁrst to forge alliances between science and the Norwegian government to investigate space, and between science and international industry to resolve an emerging crisis in feeding the growing global population. Olaf Kristian Bernhard Birkeland was born in Kristiania on December 13, 1867 and died in Tokyo on June 15, 1917. Although his birth certiﬁcate reads “Christian”, as an adult he used only his second name, which he spelled “Kristian”. In publications after 1898, he simply referred to himself as Kr. Birkeland. Birkeland’s life spans a watershed period when insights about electricity and magnetism, codiﬁed by Maxwell in the mid-19th century, evolved from theoretical curiosities to become the basis for electronic technology and eventually for our understanding of the geospace environment. Friends and colleagues universally recognized Birkeland as a gifted man with a wonderfully inventive mind that bubbled with ideas and sought to investigate every aspect of the physical sciences. In June 1890, Birkeland completed university studies in physics, graduating youngest in his class with the highest grades. In January 1893, he was awarded a universitetsstipendiat, equivalent to a Research Assistantship, at the University of Kristiania. Much of his early research was conducted in France, Switzerland, and Germany between January 1893 and August 1895. During this period, Birkeland published two theoretical

INTRODUCTION

3

papers that drew wide attention. His mathematical training in Norway provided a superb foundation for developing the ﬁrst general solution of Maxwell’s equations. He continued to investigate the properties of electromagnetic waves in conductors and wave propagation through space. At the age of 28, he was elected to be a member of the Norwegian Academy for Science and Letters. In the Academy’s 150-years history, only the famous Arctic explorer and oceanographer Fridtjof Nansen (1861–1930) was elected at a younger age. In October 1898, Birkeland was called by King Oscar II of Sweden to be senior Professor of Physics at the University of Kristiania. At that time, he was the youngest professor on the faculty. Because he looked younger than his age, for several years he was called “the boy professor”. In 1906, he was elected a fellow at the Faraday Society of London and in 1908 received an honorary doctorate, Doktor Ingenieur Honoris Causa, from the Dresden Technical University in Germany. Birkeland married Ida Augusta Charlotte Hammer, who was four years his senior, in May 1905. She was a teacher of cooking at a girl’s school near Kristiania. They had no children and the marriage was not happy. They formally divorced in January 1911, after nearly two years of separation. While Professor of Physics at The Royal Frederik University in Kristiania (1898–1917), Birkeland laid foundations for our current understanding of geomagnetism and polar auroras. In 1901, Birkeland initiated a new set of laboratory simulations that he called T Terrella Experiments. He hoped to prove incontrovertibly the correctness of his theoretical interpretation of auroral and geomagnetic disturbances. For the ﬁrst time cosmic phenomena were scaled and simulated in a laboratory. His terrella experiments were at once simple and ingenious. His largest chamber was a full cubic meter in volume. He fully believed that the laboratory simulations conﬁrmed his understanding of auroras. They opened new paths suggesting how electromagnetic forces might operate in the solar system. Birkeland’s laboratory simulations were brilliant successes that allowed him to argue by analogy about the causes of auroras and geomagnetic disturbances. In 1899, Birkeland built the ﬁrst permanent auroral observatory in northern Norway atop a 900-meter mountain. He conducted three auroral and geomagnetic expeditions between 1897 and 1903. Of these, his four-station polar expedition during the winter of 1902–1903 was the most important. After 1906, Birkeland extended his terrella experiments and applied the electromagnetic theory to include solar and cosmic phenomena. His simulations of the inﬂuence of corpuscular radiation from the Sun on Saturn’s rings, and comet tails are fascinating, especially coming at a time when other scientists maintained that the Earth was surrounded by vacuum. His concepts of stars as sources of matter for interstellar space and the importance of electromagnetic forces throughout the cosmos are markedly less known. His theoretical

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Figure 1. King Oscar II appointed Birkeland Professor of Physics in October 1898. The appointF ment was announced in a formal, four-page document. In accepting this appointment Birkeland promised to support royal authority.

proposals were rooted in laboratory experiments designed to simulate space interactions. Birkeland blended a unique intuition with talent for technical work. His approach generated fruitful frameworks for understanding basic plasma processes. Birkeland published eighty-eight scientiﬁc papers; thirty-two of them appeared in Comptes Rendus des Sciences, the journal of the French Academy. The others were published in German, Scandinavian, and English journals. He also wrote three scientiﬁc books. His main treatise The Norwegian Aurora Polaris Expedition of 1902–1903 ﬁlls more than 800 pages in large format. The P other two books are about 200 pages in length. Research activities in many different ﬁelds were new to Norway. As many as eight research assistants worked in his laboratory. Several scientists have ranked him among the world’s leading experimental physicists. (cf. e.g. Peratt r , 1996). From 1901 to 1906 Birkeland turned to applied physics and technological development. His primary motive for engaging in this activity was to generate the funds needed to support ambitious research projects and to build a modern research laboratory whose cost greatly exceeded what the University could afford. All together Birkeland developed sixty patents in ten different subject

INTRODUCTION

5

areas. In one ﬁeld, the production of agricultural fertilizers, he earned large sums of money. Birkeland invented the plasma arc leading to the Birkeland-Eyde method for industrial nitrogen ﬁxation and the founding of Norsk Hydro that today remains one of Norway’s largest industrial enterprises. While Norwegians mostly remember him for his leading role establishing Norsk Hydro, Birkeland viewed the effort as a diversionary episode in his life. Birkeland’s ﬁrst patent concerned an electromagnetic cannon that is similar in concept to a rail gun. He then formed his ﬁrst company called Birkeland’s Firearms. A modern rail gun was used to simulate how the Space Shuttle Columbia’s left wing was breached by a high-speed packet of foam. Birkeland also held patents related to electrical switches and even formed a small company for their industrial production. He also took out patents related to hardening whale oil to produce magarine, electromagnetic devices to probe for metals and w minerals, the reﬁning of oil, and mechanical hearing aids. In 1906, Birkeland applied for funds from international ﬁnanciers in Stockholm to support research for utilizing atomic energy; in 1915, he sought support to build automated meteorological stations to improve severe weather predictions. From 1908 to 1910 he conducted extensive radiowave experiments related to telegraph and telephone technology. To help improve radio communications capabilities, at his own expense, Birkeland erected a 15-meter high transmitter antenna on the roof of the University’s main building and built receiving stations a few miles away. Birkeland’s pioneering research in geophysics and applied physics engendered a widespread spirit of pride in his newly independent homeland. On February 1, 1913, the front page of the Aftenposten, Norway’s largest newspaper, featured a summary of a lecture Birkeland had presented to the Norwegian Academy on the previous evening with King H˚a˚ kon VII sitting in the front row. His ability to attract and stimulate young scientists laid the foundations for Norway’s strong presence in present-day space research. Many of Birkeland’s insights about the physics of space passed unrecognized until satellites gave us the ability to survey electromagnetic environments beyond our atmosphere. He introduced basic concepts that are central to modern space physics. They include calculations of energetic-particle motions in dipolar magnetic ﬁelds, his description of geomagnetic substorms, and his postulate that electric currents ﬂow along magnetic ﬁeld lines into and out of the upper atmosphere, today called the Birkeland currents. These currents link the upper atmosphere to the distant reaches of geospace. He also discovered the global pattern of the electric currents in the polar ionosphere. Based on his own laboratory simulations, Birkeland ﬁrst suggested that how charged particles from the Sun control geomagnetic disturbances and might inﬂuence such interplanetary phenomena as Saturn’s rings, comet tails, and zodiacal light. As space

6

INTRODUCTION

measurements accumulated in the 1970s, attitudes towards Birkeland’s work on electric currents in space changed to admiration and acceptance. In retrospect, we see that Birkeland’s geomagnetic and auroral research, conducted between 1894 and 1913, was decades ahead of its time. Birkeland was tireless, energetic, and enthusiastic, constantly involved in simultaneous projects. Thus, he often worked both days and nights. He introduced innumerable ideas but never spared himself. He possessed a lively imagination and a sense of humor that tended toward self-deprecation. Some ffaculty colleagues were envious of Birkeland’s ability to attract generous government support for his research. He identiﬁed and employed many promising young students who grew to become important leaders in the Norwegian scientiﬁc community. Among these were Sem Sæland, Carl Størmer, Lars Vegard, Ole A. Krogness, Thorald Skolem, Karl and Olaf Devik. They all contributed to the development of cosmic geophysics, a new ﬁeld of research started by Birkeland. He disliked the University’s formal criteria for appointing new professors, and often voted with the minority. Feeling that the University had too many German-speaking professors, Birkeland actively supported the candidacy of chemist Ellen Gleditsch, a former assistant to Madam Curie, to become the ﬁrst female member of the faculty. Olaf Devik (1971) described Birkeland’s lectures: “When he lectured on a subject which he was especially fond of, he brought a breath of fresh air into the classroom. He would operate electrical equipment far beyond their rated capacities and burn out 100 Ampere fuses with digniﬁed nonchalance” (Devik, 1971). He seldom hesitated to disagree with explanations in physics textbooks. As his research responsibilities grew, Birkeland found less and less time to prepare and give lectures, and often paid his assistants to teach introductory courses. The concept of maintaining good health with regular exercise and a good diet was alien to Birkeland’s mind. He always worked hard, and his assistants often had to remind him to eat lunch. From his days as a student, he experienced frequent bouts of insomnia. Some of his early radiowave experiments led to serious hearing defects. In his later years, Birkeland grew even more absentminded and disorganized in his daily life. He jotted small notes about schedules, budgets, and scientiﬁc ideas on single sheets of paper, then left them in random places. A rapid deterioration in his health was a critical factor in Birkeland’s decision to emigrate to Egypt in 1913. The last two years of his life were particularly difﬁcult. He slept poorly and became inordinately suspicious of strangers. Birkeland’s life also spanned a period of political change, from whose inﬂuence not even theoretical physicists are exempt. Incorporated into the Swedish Kingdom in 1814 after the Napoleonic wars, Norwegians found themselves

INTRODUCTION

7

mired in a political and economic backwater. Between 1840 and 1900, more than 600,000 Norwegians emigrated to the United States. Others stayed and struggled for an independent Norway. Birkeland always viewed his scientiﬁc and applied work through the prism of Norway’s contribution to civilization. Although he was very much a Norwegian nationalist, he was also a European cosmopolitan. In the summer of 1914, the century-long peace established at the Congress of Vienna collapsed while Birkeland was in Egypt conducting research on a solar effect called zodiacal light. His two young assistants were recalled to Norway for military service. In early 1917, alone and in poor health Birkeland decided to return to Norway. The war dictated that he travel to Kristiania via Japan and the TransSiberian railroad from Vladivostok. His companion, Dr. Eriksen, the Danish Consul to Egypt, was on his way back to Copenhagen. However, when they reached Tokyo in early May, Eriksen changed his plans and returned to Egypt. Birkeland died in Tokyo about a month later, an indirect casualty of the conﬂagration we now call World War I. In the course of our research for this book, we uncovered documents from May and June 1917 that cast new light on Birkeland’s last days in Japan. At the University commemoration of Birkeland’s death in 1917, ViceChancellor Sæland characterized Birkeland as “a scientiﬁc explorer by the grace of God.” In the eyes of all Norwegians he was both famous and wealthy. At the time of his death, an international committee was in the process of nominating him for the Nobel Prize in Physics. Altogether he was nominated for a Nobel Prize four times each in chemistry and physics. The government of Norway honored Kristian Birkeland as the world’s ﬁrst space physicist. His portrait, along with his terrella experiment and some original drawings, appears on the 200 kroner banknote, ﬁrst issued in 1994. In addition, a large international Birkeland Symposium was held in 1967, and the annual series of Birkeland lectures was established at the Norwegian Academy for Science and Letters. Birkeland was the complete scientist, a gifted theorist, as well as an imaginative laboratory and ﬁeld experimentalist. He devised laboratory experiments that, for their time, were of unprecedented size and complexity, and he made them work. Many studies have been made of eminent scientists. Some scholars are purposeful, follow straight lines toward their goals, and never allow interruptions or distractions. Others take a different approach. Like gardeners who develop hybrid roses, they try many different methods and techniques with varying degrees of success. Birkeland belongs to this latter category. To begin to understand Birkeland’s accomplishments and the arguments against them, we must set aside the technological world we take for granted and imagine ourselves at the end of the 19th century. We must continually ask,

8

INTRODUCTION

“What did scientists of the time know?” For example, although Birkeland began working with “cathode rays” in 1894, it was not until 1897 that Joseph John Thomson (1856–1940) identiﬁed them as the electrical corpuscles we now call electrons. With this knowledge, Thomson developed a model in which positive and negative charge was distributed more or less uniformly throughout the atomic volume. However, Thomson’s model wrongly predicts atomic emission spectra. It was not until 1910 that Ernest Rutherford (1871–1937) experimentally demonstrated that atoms consist of electrons orbiting very small nuclei of positive charge. According to Maxwell’s equations, electrons in Rutherford’s planetary atom should radiate energy as light and collapse into the nucleus. In 1913, Niels Bohr (1885–1962) took the ﬁrst step toward understanding the quantum universe we take for granted today. There is also a problem of language. The 19th and early 20th centuries were times of singular growth in scientiﬁc understanding. Reading early papers challenges scientists accustomed to textbooks written after World War II. Standard terminology, mathematical notation, and physical units have now evolved that allow readers access to the thoughts of American, European, or Asian scientists without requiring mental gymnastics to map between them. However, reaching this stage of synthesis required the uniﬁcation of partially described phenomena and diverse metaphors into a common nomenclature. Like any explorer, Birkeland had to invent new language as his research uncovered new layers of physics. As the ﬁrst to examine disturbance records from around the globe during magnetic storms, Birkeland estimated that currents of several millions Amperes must ﬂow in the upper atmosphere. He understood intuitively that only the Sun could drive and sustain such large electrical currents. Consequently, currents in the upper atmosphere must connect to generators in deep space via magnetically ﬁeld-aligned currents. Indeed, Birkeland found the predicted currents replicated in laboratory simulations. He reached truly innovative conclusions about the physics of the aurora and disturbances in the Earth’s magnetic ﬁeld. Others shared neither Birkeland’s intuition nor his trust in laboratory simulations and felt they could explain magnetic perturbations observed on the ground as the results of a system of equivalent currents ﬂowing in the upper atmosphere. Decades passed before Naoshi Fukushima showed in 1969 that it is impossible to distinguish between Birkeland’s and the equivalent-current systems based on ground magnetic records alone. Field-aligned currents can only be detected with magnetometers on spacecraft ﬂying above ionospheric current layers. Scientists are human beings who may feel tribal loyalties that blind them to truths expressed in unfamiliar words. In 1892, William Thomson (1824–1907), better known as Lord Kelvin, expressed his opinion that no matter passes between the Sun and the Earth. In spite of mounting evidence to

INTRODUCTION

9

the contrary, Kelvin’s opinion was deﬁnitively rejected only after satellites had passed though the boundary of the Earth’s magnetic ﬁeld into the solar wind. Writing a scientiﬁc biography of Kristian Birkeland about a century removed from the time of his greatest achievements presents two further difﬁculties. First, Birkeland was an extraordinary theoretical, experimental, and applied physicist whose interests were both broad and urgent. Coming from a middle class family, he lacked the independent resources needed to support his scientiﬁc investigations. An international scholarship and his inexpensive but ingenious experiments at the University of Kristiania established his scientiﬁc reputation at a time when Norway sorely needed heroes. This renown provided entr´e´ e and credibility when he approached the Storting, Norway’s parliament, in search of funds to support challenging ﬁeld experiments. It also attracted the attention of industrialists who approached the Norwegian Wunderkind W for advice in solving practical problems. In the ﬁrst decades of the new century, Birkeland analyzed and published the results of his laboratory experiments while developing new practical concepts and demonstrations to support sixty patents. More and more Birkeland invested money earned from industrial inventions to support his scientiﬁc research. Because he was involved in so many projects at once, a simple chronological listing of events would lead to confusion. For this reason, we chose to pursue a thematic development. A second difﬁculty arises from the fact that Birkeland never kept a diary. Most of our knowledge of him as a schoolboy, as a university student, in his private life and marriage as well as his conﬂicts with Sam Eyde and Carl Størmer is largely based on the writings and recollections of his close assistants, Sem Sæland, Ole A. Krogness, and the Devik brothers, Olaf and Karl. They regarded Birkeland as a genius. One of the authors (A.E.) conducted extensive interviews with Olaf Devik and was given full access to his archives. In The Norwegian Aurora Polaris Expedition of 1902–1903, w which we refer to as NAPE, Birkeland does discuss the development of his thoughts concerning N laboratory and ﬁeld experiments. He also provides candid descriptions of and his reactions to physical hardships and dangers experienced during the auroral expeditions. In addition, he planned to write Volume III, mainly concentrating on auroral physics and the results of experiments with his 70-cm diameter terrella. Unfortunately, Birkeland died before this volume was written. Shortly after his death in Tokyo, colleagues assembled all of Birkeland’s scientiﬁc papers for return to Norway. The ship bearing the papers was lost at sea, and with it access to Birkeland’s mature thoughts on auroral phenomena. At the present time, Birkeland’s name and contributions are not well known outside Scandinavia. External recognition is mostly conﬁned to scientists who study the Earth’s space environment. Even among them, appreciation of Birkeland’s work is fragmentary, mainly concerned with the ﬁeld-aligned

10

INTRODUCTION

currents that electrically couple the ionosphere to deep space. His laboratory simulations of the solar system and his technological innovations remain largely unknown. Lucy Jago’s book The Northern Lights (2001) is the most comprehensive biography of Kristian Birkeland available in English. The book is well written in a journalistic style that necessitated telescoping events and, in the absence of documentation, making “reasonable” assumptions about what actually occurred. It strongly emphasizes Birkeland’s personality and the reactions of others to him. We share much common ground. However, as auroral scientists, we emphasize Birkeland’s documented scientiﬁc and technological accomplishments and his place within the development of space physics over the past century. This book is divided into ﬁve major sections, each with two or three chapters. The ﬁrst sets the stage with brief summaries of the political and scientiﬁc status of Norway at the end of the 19th century. It also describes the Birkeland family and Kristian’s education through postgraduate studies. The second section deals sequentially with Birkeland’s geomagnetic and solar system research. His geomagnetic studies were conducted during ﬁeld expeditions and in laboratory simulations with the terrella serving as an anode to attract energetic electrons from the “Sun”. In his solar system simulations, Birkeland reversed the electric polarity of the terrella to simulate the origin of sunspots and comet tails. From these experiments, he came to a profound realization that the universe must be ﬁlled with ionized gas that we now call plasma. The third section deals with Birkeland’s technological inventions related to high-current switches, electromagnetic cannons, and nitrogen-ﬁxated fertilizers. The fourth and ﬁfth sections, respectively, describe Birkeland the man as perceived through available documents and interviews with Olaf Devik, and his heritage in Norwegian education and space physics. In addition to the standard references at the end of the book, interested readers can also ﬁnd copies of several previously unavailable documents as well as lists of Birkeland’s publications and patents.

Part I: Background and Education

CHAPTER 1

AT THE 19TH CENTURY’S END

1.1 UNION OF NORWAY AND SWEDEN In the aftermath of the Napoleonic wars, England and Russia agreed that Norway should become a part of the Swedish kingdom. From the outset the Union was unstable. In 1814, the year of the forced union, Norwegians ratiﬁed their own constitution. They experienced two bothersome limitations to their autonomy. First, Norway was not free to appoint its own foreign ambassadors. Second, their Swedish King held veto power over enactments of the Norwegian Storting (Norway’s parliament). Relations between Sweden and Norway deteriorated severely in the ﬁrst half of 1905, leading to the Union’s dissolution. On June 1, 1905, King Oscar II of Sweden vetoed a Norwegian resolution to form its own Consular Service. The Storting declared that the King’s action was unconstitutional. Existing law allowed the king to exercise a veto only with the concurrence of his cabinet. Norway unilaterally ruptured the Union on July 7, 1905, and waited anxiously to see if Sweden would declare war. In the months before the ﬁnal break, the Storting prudently consulted with critical countries to assure international acceptance for their independence initiative. The world-famous Norwegian explorer and oceanographer Fridtjof Nansen (1861– 1930) helped carry the day by persuading the British government to support separation. A September plebiscite, in which only men could vote, certiﬁed the degree of popular support for dissolving the Union. Almost unanimously Norwegians voted to end the Union, 368,208 for and 184 against. A second referendum, held in November, decided whether newly independent Norway would become a republic or remain a constitutional monarchy. Newspaper editors and other prominent citizens encouraged votes for a monarchy, hoping that a Swedish prince would be chosen as the king and thus maintain good relations with the strong neighbor. When the Swedish prince declined, Norway turned to the Danish prince Carl who accepted and assumed the Norse royal name H˚a˚ kon VII.

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Figure 2. The Royal Frederik University of Kristiania and University Square as they looked when F Birkeland was a student. Birkeland’s ofﬁce and laboratory were in the Domus Media, behind the column fa¸c¸ ade.

1.2 THE ROYAL FREDERIK UNIVERSITY IN KRISTIANIA In 1811, King Frederik VI of Denmark established Det Kongelige Frederiks Universitet (The Royal Frederik University) in Norway’s capital, Kristiania. It was renamed University of Oslo in 1939. Following Birkeland’s example in his main book, The Norwegian Aurora Polaris Expedition of 1902–1903, we simply refer to it as the University of Kristiania. In the beginning, the University was scattered throughout the city. The Astronomical Observatory (1832) was the ﬁrst building speciﬁcally built for the University. In 1851, the University moved into the new Domus Media around which the main campus formed. This was centrally located on the city’s main street, Karl Johan Gate 47 (Gate is the Norwegian word for street). At the beginning of the 20th century, it was still the largest building along the street. Figure 2 shows its impressive ¸ of columns and shallow steps. The Royal Castle and the Storting were facade its nearest neighbors to the north and south, respectively. The physics group moved into Domus Media in 1851. Not long afterwards, two other monumental buildings were completed on the new campus. The main university library, Domus Academica, with several lecture halls lies to the west of Domus Media, and to the east is the ﬁrst festival building later known as the Old Banquet Hall. The Philosophy Faculty then had two major sections. The ﬁrst concerned the disciplines of philosophy and history, the second mathematics and science. By 1860, an institute of physics was recognized with its own faculty. In 1891, the institute became the Department of Physics.

AT THE 19TH CENTURY’S END

13

Figure 3. Christofer Hansteen (1774–1873), the ﬁrst professor at the University of Kristiania F to study geomagnetism and auroral lights. A fascinating researcher, Hansteen had a profound inﬂuence on the University’s early development.

Christofer Hansteen (1784–1873), shown in Figure 3, was a character central to the University of Kristiania’s development. A Norwegian by birth, Hansteen received his scientiﬁc education at the University of Copenhagen under the direction of Professor Hans Christian Ørsted (1777–1851). We return to Ørsted and Hansteen in our discussion of geomagnetism. In 1816, Hansteen returned to Norway to become the University’s ﬁrst Professor of Astronomy and Applied Mathematics. He was the driving force responsible for building the Astronomical Observatory on land that would become a part of the University campus. By 1885, when Birkeland entered the University, the total number of students and faculty was nearly 600. There was a single Professor of Physics, Oscar Emil Schiøtz (1846–1924). However, Birkeland worked more closely with Carl Anton Bjerknes (1825–1903), Professor of Applied Mathematics and father of his friend Vilhelm Bjerknes (1862–1951). The younger Bjerknes later gained international fame for his work on the meteorology of weather fronts. Two other professors who greatly inﬂuenced Birkeland were Hans Geelmuyden (1844– 1920), head of the Astronomical Observatory, and Henrik Mohn (1835–1916), director of the newly established Meteorological Institute. 1.3 EARLY INVESTIGATION OF THE AURORA AND GEOMAGNETISM The beauty and mystery of shimmering auroral lights in the polar sky have long fascinated humanity (cf. e.g. Brekke and Egeland, 1994). These glorious

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CHAPTER 1

lights have many names. In his treatise on Meteorology, Aristotle (384–322 B.C.E) referred to them as χασ µατ α (chasms or cracks in the sky) shining with blood-red light. For the Vikings, they were simply “northern lights”. Early modern scientists such as Galileo (1564–1642) and Pierre Gassendi (1592– 1656) used the Latin aurora borealis or “northern dawn” to describe their red appearance at the latitudes of southern Europe. In 1770, during the voyage of Endeavor, Captain James Cook (1728–1779) was the ﬁrst European to observe auroral lights in the southern hemisphere (aurora australis). Birkeland used the term aurora polaris to indicate that auroral phenomena occur at magnetic high latitudes in both hemispheres. For many centuries, the magnetic properties of lodestones and magnetite were known and used as navigational aids. William Gilbert (1544–1603) conducted the ﬁrst systematic investigation of the Earth’s magnetic ﬁeld and published the results in De Magnete (1600). His most important conclusion was that “the Earth itself is a large magnet” with its greatest strength at the poles. Gilbert also noted that the magnetic poles are displaced by a few degrees from the geographic poles. Scientists [Gilbert (1600); Gauss (1839, 1841); Chapman and Bartels (1940)] long recognized that the Earth’s magnetic ﬁeld changes continually and often violently. When Galileo ﬁrst turned his telescope on the Sun in 1610, he discovered that it lacked the perfectly smooth surface postulated by Aristotelian cosmology. Rather it was pocked by blemishes now called sunspots. Thereafter, the behavior of sunspot activity was carefully monitored. However, it was not until the 1840s that Heinrich Schwabe (1789–1875) showed that the number of sunspots varies considerably over an 11-year cycle. In 1716, Edmund Halley (1656–1742) found a close association between geomagnetic disturbances and visible auroral displays. During the year 1741, Anders Celsius (1701–1744) and Olaf Peter Hiorter (1696–1750) conducted investigations in which they noticed that the orientation of a suspended magnetic needle tilted either to the left or right of the geomagnetic pole direction whenever auroral lights were visible. Clearly, auroral perturbations of comw pass directions posed serious threats to navigation. However, Celsius could not explain why an auroral display affected compass directions. More than a century later, Birkeland proposed the ﬁrst scientiﬁcally correct explanation of this mysterious relationship. He argued that ﬂuctuations of the geomagnetic ﬁeld m provide critical information about the electrical currents ﬂowing in the Earth’s space environment and about activity on the Sun. While the Earth’s atmosphere protects us from hazardous radiation, most information carried by magnetic ﬁeld variations reaches the ground. During the early years of the 19th century, while Christofer Hansteen was studying at the University of Copenhagen, the Danish physicist Hans Christian

AT THE 19TH CENTURY’S END

15

Ørsted (1777–1851) was examining changes in the orientations of magnetic needles whenever electric currents ﬂowed in nearby wires. In 1820, Ørsted published his discovery that electric currents cause magnetic disturbances. Later, Michael Faraday (1791–1867) demonstrated that time-varying magnetic ﬁelds induce electric currents. James Clerk Maxwell (1831–1879) uniﬁed the work of Ørsted and Faraday, expressed in four fundamental laws of electromagnetism. As Ørsted’s student, Hansteen was aware that Halley detected similar deﬂections of compass needles during auroral displays. In 1812, Hansteen entered a European competition to answer the question: “Can we explain the Earth’s magnetic phenomena with a single magnetic axis, or must several axes be assumed?” Hansteen’s (1819) thesis Untersuchung u¨ ber den Magnetismus der Erde won the competition. He concluded that two axes, or four magnetic poles were needed to explain existing measurements of the Earth’s magnetic declination. The concept of a quadrapole magnetic ﬁeld was not new. Hansteen cited it as part of Halley’s geomagnetic model, and he spent a good deal of time trying to determine where to place the four poles on a globe. Hansteen built several new instruments for measuring the total ﬁeld and the magnetic declination to support his geomagnetism studies. Between 1828 and 1830, he traveled across Siberia to China to look for the second pole on the northern hemisphere. Although he never found a fourth magnetic pole, the global magnetic map he derived during this expedition was of considerable use to Carl Friedrich Gauss (1777–1855). Although the auroral problem was not of central interest to Hansteen, in 1825, he surmised: “The northern lights must be part of a shining ring, with a diameter of about 4,000 kilometers, of which each observer sees his own segment. This leads us to suppose that there must be some connection between r , 1885). Much later the aurora and the Earth’s magnetism.” (cf. e.g. Tromholt in the 19th century, Herman Fritz (1830–1893) in 1881 clearly documented that the auroral lights most often occur about 23◦ from the magnetic poles. Systematic recordings of simultaneous geomagnetic ﬁeld variations began in 1834, when Carl Friedrich Gauss ﬁrst deployed magnetometers of the Gøttingen Magnetic Union at stations around Europe. Gauss’ publication Algemeine Theorie des Erdmagnetismus (1839) initiated the modern study of geomagnetism by applying the gravitation potential theory of Pierre-Simon Laplace (1749– 1827) to the Earth’s magnetic ﬁeld. Gauss argued that magnetic ﬁelds detected on the ground have sources inside Bint and outside Bext the Earth. He then demonstrated a mathematical technique to separate them. He concluded that Bint was due to a large, permanent ﬁeld from inside the Earth that varies from approximately 30,000 to 60,000 nanotesla (nT) between the geomagnetic equator and the poles. The magnetic-ﬁeld axis tilts about 11◦ to the Earth’s rotational axis. To a good approximation, the geomagnetic ﬁeld is represented by a simple

16

CHAPTER 1

dipole. Currents ﬂowing somewhere above the Earth cause the external ﬁeld, which is much weaker than Bint . Bext varies from approximately 50 nT on quiet w days to more than 3,000 nT during magnetic storms. Large disturbances tend to occur at polar latitudes, but the cause of these disturbances remained obscure. Birkeland resolved this question as well. Following the discovery of cathode rays, Eugen Goldstein (1850–1930) suggested the possibility that electric currents ﬂow out of the Sun. In 1882, the Scottish physicist Balfour Stewart (1828–1887) suggested that electric currents also ﬂow in the tenuous upper atmosphere, later called the ionosphere. They may well be the source of day-to-night differences in magnetic perturbations δBext observed on the ground surface at mid-latitudes. In 1902, a year before Gulielmo Marconi (1874–1937) transmitted radio waves across the Atlantic Ocean, Arthur E. Kennelly (1861–1939) and Oliver Heaviside (1850–1925) independently argued that a layer of ionized gas (now referred to as plasma) must exist in the upper atmosphere. The ionosphere’s existence was not fully established until about 1930 by Sir Edward Appleton (1892–1965) and Douglas R. Hartree (1897–1958) in Great Britain.

CHAPTER 2

A NEW ABEL

2.1 THE BIRKELAND FAMILY Olaf Kristian Bernard Birkeland was born in Kristiania on December 13, 1867. As an adult he used only his second name, Kristian. For many generations, his ancestors were farmers from a small community called Birkeland in the southernmost part of Norway. His grandfather had an amateur’s intense interest in natural science. Kristian’s father, Reinert Tønnesen Birkeland (1838–1899) was born near Flekkefjord, a town in southern Norway. In 1864, shortly after his marriage to Ingeborg Susanne Ege (1841–1913), he and his bride moved to Kristiania. With the help and advice of an uncle who had a small shop, Reinert established himself as a merchant in the import–export business. In the latter half of the 19th century, emigration from Norway was second its peak. At the time, Norway was second to Ireland in the rate of emigration to the United States. For their ﬁrst 20 years in Kristiania business was very good, providing the family with a comfortable income and a standard of living that included a maid to help with chores. They lived on the second ﬂoor of a four-story apartment building at the corner of Langes Gate and Nordahl Bruns Gate, roughly a kilometer to the east of the University. For its time, the Birkeland home was quite modern, with electricity and indoor plumbing. Their ﬁrst son Tønnes Gunnar was born on October 26, 1865, about two years before Kristian. Tønnes Gunnar was physically strong and an active participant in all kinds of sports throughout his life. Kristian on the other hand was small, needed glasses even as a child, and was often sick. He seldom went on hiking trips in the open forests to the north of their home. Kristian was very much a city boy having little contact with the part of his family living in the countryside. Still, the younger son was very active, normally in good spirits, and gifted with a keen sense of humor. Kristian had an aptitude for learning and showed an interest in mathematics, chemistry, and physics. Early on Kristian recognized his own talents in science. Initially, the family owned few books. However, since Kristian spent so much time at home, his parents continually purchased new books for him. He used all his pocket money to buy tools and materials to conduct experiments. He also enjoyed playing science-based tricks on his school friends. As a schoolboy Birkeland was fascinated with magnets, his ﬁrst

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purchase with his own money. He often took his magnet to school where he performed scientiﬁc demonstrations. He also carried out several experiments in chemistry. Even then it was clear that Birkeland possessed a strong scientiﬁc intuition and hinted that later the Earth’s magnetic ﬁeld would be one of his research topics. The Birkeland boys grew up in a typical middle-class Norwegian ffamily, with their parents urging them to pursue university degrees. In the mid-1880s, friction between Norway and Sweden worsened. Sweden imposed trade sanctions that severely crippled many Norwegian businesses. Reinert Birkeland fell into a depression, and gradually isolated himself from the family so that Kristian had little contact with him. He died in September 1899 at the age of 61 years. Kristian’s mother was physically short, but she was a very strong woman. During the last decade of Reinert’s life, she was the family breadwinner who kept the business going. Less than a year after becoming a widow, she decided to close the shop and move to Porsgrunn where she lived her remaining years with Tønnes Gunnar. He was then a private medical doctor in Porsgrunn a town located along the sea between Norway and Denmark, roughly 250 km southwest of Kristiania. Tønnes married early and fathered nine children. Although the journey from Kristiania to Porsgrunn took half a day by boat and slightly less by train, Birkeland seems to have had little subsequent contact with his mother or brother except for a few letters and phone calls. His mother’s departure from Kristiania took place shortly after Kristian returned from the Haldde expedition. She died in February 1913 at the age of 72. The two Birkeland boys were of very different temperaments. Tønnes Gunnar (1865–1951) was an active competitor in athletics who loved hiking. Soon after completing his medical education at the University of Kristiania in 1891, Tønnes Gunnar left home to practice medicine in several counties outside the capital. In 1906 he became the town doctor in Porsgrunn, where he remained for the rest of his life. Porsgrunn later became a central location for Norsk Hydro. Although Kristian suffered many health problems after the age of 30, we found no documents indicating that he consulted his brother for medical advice. After Kristian became rich and famous, the brothers had little social contact. A few letters survive in which Tønnes describes how hard it was for him as a medical doctor to earn enough to feed his large family. Thus, he would appreciate receiving clothing, shoes, books, and money. Tønnes had to contact Kaja Geelmuyden and the Devik brothers to learn about Kristian’s move from Egypt to Japan and his last days. He received copies of the last letters from Kristian. In contrast to his brother, Tønnes lived to the ripe old age of 86 years. Kristian Birkeland’s best-known relative was his ﬁrst cousin Richard Birkeland (1879–1928), also from southern Norway, who ﬁnished a master’s

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degree in mathematics at the University of Kristiania in 1903. After completing doctoral research under Professor Carl Størmer (1874–1957), he studied for two years (1906–1908) in Germany and France. Richard was appointed Professor of Applied Mathematics at the Technical University in Trondheim in 1910. In the early 20th century, Norway had few professors; two from the same family of farmers with no university backgrounds was regarded as exceptional. Kristian was already well-known from the many articles written by or about him in Norwegian newspapers. Richard and Kristian collaborated scientiﬁcally only once, on a study of the rings of Saturn. In 1908, Richard discovered a serious error in one of Størmer’s papers and asked Kristian for advice on how to handle the situation. Subsequently, relations with Størmer deteriorated. From 1920 to 1923, Richard was Vice-Chancellor at the University of Trondheim. Shortly thereafter he moved to Oslo to become Professor of Mathematics at the University of Kristiania. He even occupied the same ofﬁce as his famous cousin. Surviving reports indicate that Richard was an excellent teacher and a popular adviser of students. He died at the age of 49.

2.2 HIGH SCHOOL AND UNIVERSITY EDUCATION Both Tønnes and Kristian attended a well-known, private high school, Aars og Voss Latin-og Realskole located on St. Olav Gate about 1 kilometer from their V home. When Birkeland matriculated in 1881, the school had about 750 pupils in 30 different classes. Aars og Voss was one of the few high schools where one could choose to study science and modern languages instead of Latin. At the time, Latin was still used as a language of international discourse, so it was the major chosen by most pupils. Among the modern languages, French and German were more widely known to contemporary Norwegians than English. Both of the Birkeland brothers chose the science course. Birkeland’s parents had to pay 240 kroner per year for their children’s tuition, then equivalent to a full month’s salary for a senior high school teacher. Kristian enjoyed school, especially, the science part of the curriculum. Birkeland’s mathematics teacher at Aars og Voss was Elling Bolt Holst (1849–1915), shown in Figure 4, who in 1890 became an Associate Professor of Mathematics at The Royal Frederik University. Kristian received very high grades and completed all academic requirements a year ahead of Tønnes Gunnar. He graduated from high school in 1885 with the highest marks in all of the scientiﬁc disciplines. Elling Holst found Birkeland to be an exceptional student. Before ﬁnishing high school Birkeland published three short papers on geometry for the Danish journal Zeuthens Tidsskrift for Mathematikk (1886, 1887). During his last year in high school, Birkeland handwrote an eighteen-page document containing

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Figure 4. Elling Bolt Holst (1849–1915) Birkeland’s high school mathematics teacher. He was F a substitute lecturer for several semesters before he was appointed Associate Professor of Mathematics at The Royal Fredrik University in 1890. Holst remained a life long inspiration to Birkeland.

several equations that he asked The Norwegian Academy to hold in storage, because he lacked time to ﬁnish it. A brief excerpt from the paper, which was published in 1914 in the journal of the French Academy under the title: Une ´ m´e´ thode Enumeractive ´ de la G´eom´ ´ etrie, ´ is shown in Figure 5. The ﬁrst half of the paper is simply a French translation of his original work. Birkeland later regarded this work at age 18 among his greatest intellectual achievements. Holst was so impressed with the paper, he asked Birkeland to be his teaching assistant. In October 1915 on the occasion of Elling Holst’s death, Birkeland wrote a letter from Egypt to his widow that said, “No other man has ever touched me as deeply as Elling when I was young and I am thankful to have known him. He was such a special person. I am collecting material for an article about him” (O. Devik’s archive). At the end of the 19th century a university degree was very unusual in Norway. On September 2, 1885, at the age of 18, Birkeland became a student at The Royal Frederik University. The curriculum was very different from today’s, requiring a year and a half pursuing the Andre Avdeling or second degree studying classical Latin and Greek literature and philosophy. High school graduation conferred the ﬁrst degree. Kristian managed to absorb enough Latin to

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Figure 5. A brief excerpt from the eighteen-page handwritten manuscript written by Birkeland F in high school.

feel comfortable using it in letters to close friends and in some of his scientiﬁc papers. After ﬁnishing the Andre Avdeling, Birkeland studied chemistry for a year under the well-known Norwegian Professor Peter Waage (1833–1900), who was impressed with how quickly Birkeland carried out the experiments and mastered the basic concepts of chemistry. At ﬁrst Waage had thought Birkeland was not studying properly, but soon discovered that he was an extraordinarily efﬁcient student. He even contacted Birkeland’s parents urging them to have their son follow a career in chemistry. However, the following year Birkeland resumed his mathematical studies under Elling Holst, who also employed Birkeland as an assistant. Throughout his university years, Kristian taught part-time at local schools and tutored private students. In this way, he paid for his own education and assisted his family ﬁnancially. Holst was not surprised when Birkeland was the only one in his class to receive a Presetres, the highest possible score. Birkeland received an unusual letter from Holst recognizing his special talent for mathematics and expressing a hope that he would become a new Abel. Niels Henrik Abel (1802–1829) was the best-known mathematician to graduate from the new University of Kristiania under the guidance of Professor Christofer Hansteen. After graduation in 1822, he studied for two years in Berlin and Paris. In 1824, he proved that it was impossible to solve general equations of the ﬁfth degree algebraically and in 1826 compiled a memorandum on transcendental functions. After returning to Norway in 1828, Abel accepted a substitute teacher of mathematics position. Later that year he was offered the position of professor at the University of Berlin, but he died before

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starting work in Germany. Abel’s seminal work led to the development of several branches of modern mathematics. Birkeland also excelled in theoretical and experimental physics. At that time, the university’s only Professor of Physics was Oscar Emil Schiøtz (1846–1924). Although his true expertise was in geology, he gave the physics lectures, and Vilhelm Bjerknes, then an assistant professor, oversaw the physics laboratory V experiments. Over the course of his career, Vilhelm Bjerknes became famous for developing critical new concepts about air circulation and weather prediction. Today we watch the march of weather fronts (Bjerknes contribution) on television and plan outside activities accordingly. As Kristian began reading scientiﬁc journals, he concentrated on studying Maxwell’s theory of electromagnetic waves and replicating experiments carried out by Heinrich Hertz (1857–1894). He was disappointed by the lack of electromagnetic theory in his textbook and in Professor Schiøtz’s ﬁnal examination. In spite of this limitation Birkeland decided to graduate in physics. His choice of physics over mathematics reﬂected his perception that he found mathematics easier to learn through self-study than physics. In June 1890, Birkeland, while the youngest in his class, completed his university studies with the highest grades. His degree Matematisk Naturvitenskapelig Lærereksamen is roughly equivalent to a modern master of science in physics. He was qualiﬁed to teach at a high-school level in three subjects, but he really hoped to continue his education abroad. His brother Tønnes graduated from the university a year later with a degree in medicine. 2.3 POSTGRADUATE RESEARCH IN FRANCE, SWITZERLAND, AND GERMANY Between the summer of 1890 and the end of 1892, Birkeland taught at Aars og Voss high school, but continued to work part-time for Professors Holst and V Schiøtz, conducting radio experiments in the laboratory. In January 1893 he was employed as universitetsstipendiat, equivalent to a Research Assistant. The salary was not high, but the appointment gave Birkeland designated workplace at the University. Soon he was offered a scholarship to study abroad, and he planned to spend two-and-a-half years at prestigious European universities focusing on the theoretical implications of Maxwell’s equations and experiments related to radiowave propagation. Similar opportunities were unavailable in contemporary Norway. His ﬁrst important research took place in Paris under the guidance of Henri Poincar´e (1854–1913), internationally known for his contributions to mathematics, theoretical physics, and astronomy. Poincar´e simultaneously held positions at the University of Paris and at l’Ecole Polytechnique Francaise. On

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several occasions, Poincar´e even invited n Birkeland to his home, and for the next 20 years they maintained close contact. Birkeland was proud that in 1896 Poincar´e chose to publish a paper in Comptes Rendus, titled Remarques sur une experience de Birkeland. Until Poincar´e´ ’s death at the age of 58, he remained one of Birkeland’s strongest champions within the international scientiﬁc community. In addition to Poincar´e´ , Birkeland collaborated with Professors Paul-Emile Appell (1855–1930) and Emile Picard (1856–1941) and attended their lectures for a semester. In Paris, Birkeland started his own theoretical investigations of Maxwell’s equations and the motion of charged particles in a magnetic monopole ﬁeld. When Birkeland later returned to Paris on occasion to attend meetings, he always visited Poincar´e´ . Thanks to Birkeland’s initiative, Poincar´e received an honorary doctorate from the University in Kristiania in 1902. Birkeland loved Paris and it did not take long before he could speak and read French like a native. Student friends related that he often visited restaurants and pubs where he was called simply “Monsieur Kristian”. Birkeland rented a small ﬂat in Rue de la Sorbonne, no. 6, where the landlady Mme. Rouviere took good care of him, claiming that he worked too long and did not get enough sleep. Her concern was not without basis. In a letter to his friend Vilhelm Bjerknes, sent from Paris on February 13, 1893, Birkeland wrote, “I have been in bed for four days without sleeping after a tremendous nervous freezing attack caused by too much work.” While at l’Ecole Polytechnique Francaise, Birkeland carefully studied articles in the journal of the French Scientiﬁc Academy, Comtpes Rendus des S´ Seance de l’Academie. Many of his later publications appeared in that journal. Throughout his stay in Paris, Birkeland mainly worked to deepen his understanding of Maxwell’s equations and completed several important papers. After leaving Paris, Birkeland traveled to Geneva where he worked for seven ´ months with Edouard Sarasin (1843–1917) and Lucien de la Rive (1834–1924) on problems related to geophysics. Birkeland later regarded his Geneva period as critical. He made two friends with whom he maintained close scientiﬁc and personal contact throughout his life. In their laboratory, Birkeland did his ﬁrst serious work with electric discharges. The main purpose was to make accurate measurements of discharge lengths. Within six months of his arrival in Geneva he and Sarasin co-authored two papers. In the introduction to their paper, Birkeland quoted the Latin phrase post tenebras lux (after darkness, light). From Switzerland, Birkeland moved to Bonn. Through letters he had been in contact with Heinrich Hertz, and his friend Vilhelm Bjerknes had just completed two years of postgraduate research in Bonn. Birkeland had read Hertz’s publications and was particularly looking forward to working with this now famous

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scientist on radiowave propagation experiments. However, Birkeland wrote to Holst, “cooperation with Professor Hertz turned out to be disappointing” (Devik archive). Hertz seemed to have lost interest in electromagnetic waves, and Birkeland found it difﬁcult to make personal contact with him. The most probable explanation for their disconnect was that Hertz was seriously ill and died within a few weeks of Birkeland’s arrival in Bonn. However, Birkeland was fortunate to meet Philippe E. Lenard (1862–1947) in Bonn. Lenard was the 1905 Nobel Laureate in Physics. Based on their cooperation, Birkeland produced a magnetic dielectricum that he called fferrum reductum, consisting of small pieces of iron embedded in liquid parafﬁn. In 1894, Birkeland discovered that the iron pieces would oscillate in phase with impinging radio waves and completely absorbed their electromagnetic energy. After Hertz died, Birkeland returned brieﬂy to Norway before traveling to the University of Leipzig in Germany, where he spent six months. He chose Leipzig because a colleague from the University of Kristiania, Sophus Lie (1842–1899), held a permanent position as Professor of Mathematics there. Sophus Lie had pioneered work on mathematical series and transformation theory that established his international reputation. He is Norway’s best-known mathematician after Nils Henrik Abel. Birkeland attended his lectures and discussed theoretical problems with him. Two friends from his student days, Alf Guldberg (1866–1936) and Anton Alexander (1870–1945) were also at Leipzig to study mathematics. At ﬁrst, the four Norwegian expatriates had a wonderful time together. However, Lie was unimpressed with the mathematical skills of his German students and was not reluctant to tell them so. Birkeland felt that Lie was too critical of the German education system. They argued this subject so strenuously that they eventually broke off the friendship. One humorous episode shows that Birkeland had not turned into a “soft” internationalist. As a student and later as a professor Birkeland was an unbending defender of Norway’s honor. One evening in the spring of 1895 he attended Henrik Ibsen’s (1828–1906) last play Little Eyolf, f in Leipzig’s main theatre. In the third act, an actor held a Swedish instead of a Norwegian ﬂag. Birkeland became so irate that he shouted, “Es ist eine Skandal! Eine Schwedische Flag, und Sie sollen eine Norweger sein!” (“This production is a scandal; using a Swedish ﬂag when it should be Norwegian.”) The audience was equally upset with the interruption and had Birkeland ejected from the performance. Birkeland proceeded directly to Leipzig’s largest newspaper where its editor accepted a furious note describing the scandal just witnessed in the theatre. During the next day’s performance, the ﬂag was Norwegian. This story quickly became known all over Leipzig and later even in Norway. Sophus Lie was so impressed with Birkeland’s defense of the homeland that their friendship resumed.

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The last two months of Birkeland’s study abroad were spent in Geneva, ﬁnishing a paper together with Sarasin. Before returning to Norway, he sought a six-month extension of his fellowship for study at the University of Cambridge, but his request was denied. During his two-and-a-half years abroad, Birkeland had immersed himself in new scientiﬁc ideas, and came, on a personal level, to know many of the world’s most famous scientists. Throughout his life, Birkeland strongly urged support for young candidates to work with researchers in different groups. In future years, whenever Waldemar C. Brøgger, Vice-Chancellor of the University of Kristiania, went before the Storting to argue for more funds to support international scholarships, he would always point to Birkeland as his best example. Money for education could not be spent in a more cost-effective way a than to sponsor fellowship candidates for one to two years of study abroad.

Part II: Geomagnetic and Solar System Research

CHAPTER 3

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3.1 ELECTROMAGNETIC WAVE EXPERIMENTS In 1890, Birkeland began conducting experiments in a laboratory under the University library to reproduce results published by Hertz. His friend Vilhelm Bjerknes was then working in Hertz’s group and kept Birkeland up to date. Birkeland was soon making experimental discoveries that Hertz had not reported. In his ﬁrst truly original experiment, Birkeland used a telephone as a detector to measure electromagnetic oscillations in copper wires. He also studied the absorption and reﬂection properties of electromagnetic waves in different conductors. These experiments led to his ﬁrst publication on electromagnetic waves in 1892. Of lasting value were his experiments in which the wires passed through liquids containing small pieces of iron. He thereby discovered that the iron pieces oscillated in phase with the frequencies of the imposed waves. In 1893, Birkeland submitted four papers to contributions in Comptes Rendus related to the reﬂection of electromagnetic waves. His ﬁrst paper on the effects of electromagnetic waves on small iron pieces in parafﬁn appeared in 1894. In Geneva, he and Sarasin continued their investigations of electromagnetic waves in metal cables. Speciﬁcally, they needed to understand what happened at breaks in wires. w Near the end of 1893, Birkeland turned to the energy carried by electromagnetic waves. His main purpose was to ﬁnd a general expression for the transport of radiative energy and determine when it reduces to the Poynting vector solution of Maxwell’s equations. His general expression for the Poynting vector ¨ in empty space, Uber die Strahlung electromagnetischer Energie im Raume, was derived early in 1894 and is still considered valid today. In this paper, Birkeland determined the extent to which the Poynting vector is unique (cf. Romer, 1982). Later the same year, Birkeland and Sarasin published another ¨ extensive paper in German: Uber die Reﬂexion und Resonanz der Hertz’schen electrischen Schwingungen.

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In 1894 and 1895, while studying abroad, Birkeland published nine papers. Two of them on electromagnetic theory received wide attention. His mathematical training in Norway provided a superb foundation for his ﬁrst physics endeavor, solving Maxwell’s equations. Speciﬁcally, he addressed the properties of electromagnetic waves propagating in conductors and in space. Birkeland’s main interest after he ﬁnished his university degree concerned electromagnetic waves. One of the thorniest debates among physicists revolved around the nature of visible light. Does light consist of waves as Christian Huygens (1629–1695) argued or corpuscles as Isaac Newton (1642–1727) thought? In 1895, after almost three years of work, Birkeland published his most important theoretical paper. He provided the ﬁrst general solution of Maxwell’s equations for homogeneous, isotropic media, titled: Solution g´e´ n´erale ´ des ´ Equations de Maxwell pour un milieu absorbent homog´e´ ne et isotrope (Figure 6). As one of the few physicists of his time who had mastered Maxwell’s electromagnetic theory, Birkeland addressed one of the central physics problems of the decade. His elegant solution also reﬂects his advanced grasp of mathematics. A short version appeared in Comptes Rendus. A longer, ﬁftyone page version was published in Archives des Sciences Physiques et Naturelles. Thus, between 1890 and 1895 Birkeland signiﬁcantly advanced experimental and theoretical understanding of electromagnetic waves. After 1907, he resumed his experiments with electromagnetic waves on a more extensive scale. 3.2 EARLY LABORATORY SIMULATIONS The discovery of radioactivity and X-rays in 1895 inspired Birkeland to turn from implications of Maxwell’s equations to discharge experiments in vacuum chambers. Birkeland became fascinated with auroral displays as he sought to understand natural discharge phenomena. Based on electric discharge experiments conducted in late 1895 and early 1896, Birkeland worked out details of a new auroral theory. He published ﬁve papers in 1896. The ﬁrst two appeared in Comptes Rendus (Vol. 123, pp. 492–495) under the title Sur un spectre des rayons catodiques. The second was published in Archives des Sciences Physiques et Naturelles (Vol. I, pp. 497–512) with the title Sur les rayons cathodiques sous laction ´ de forces magnetiques intenses. The Comptes Rendus paper is a shortened version of the second. Another paper from the same year has the title Cathode rays under the inﬂuence of strong, varying magnetic ﬁelds. These papers initiated modern auroral research. For the ﬁrst time, Birkeland proposed that beams of charged particles or “cathode rays” emitted from sunspots on the solar surface as a result of disintegration processes inside the Sun were important. Electrically charged beams moving toward the Earth impact its magnetic ﬁeld and are guided toward polar latitudes. Visible aurora

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Figure 6. First page from Birkeland’s 1895 paper in Comptes Rendus w F where he derived the ﬁrst general solution of Maxwell’s equations for homogeneous, isotropic media in component form.

lights result from interactions between the charged particles and the gases of the upper atmosphere. In 1896, there were several competing opinions on the nature of cathode rays. Birkeland did not refer to cathode rays as “corpuscles” explicitly until 1908. However, long before this time, he understood from the way their trajectories bent in magnetic ﬁelds that cathode rays were negatively charged. The 1896 papers contain the ﬁrst suggestion in scientiﬁc literature that auroral displays are caused by charged particles emitted from the Sun. Consequently, space between the Sun and Earth cannot be completely void of matter. Up to this time, scientists assumed that interplanetary space was a perfect vacuum. Thus, 1896 is a year of note for auroral physics and astrophysics. Birkeland’s auroral theory must be viewed in the context of today’s cosmic plasma physics. While Birkeland called the corpuscles from the Sun “a fourth state of matter”, it was not until the late 1920s that Irving Langmuir (1881–1957) introduced

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Figure 7. Illustration of Birkeland’s auroral theory. Charged particles from the Sun are guided by F the magnetic ﬁeld toward the Earth’s polar atmosphere. Hot auroral particles collide with atoms and molecules in the atmosphere. Energy is released in each collision and is used to produce excited atoms and molecules, which in turn yield the aurora.

the term “plasma” to describe ionized gases. Many years passed before the geomagnetic community universally accepted the concept of charged particles from the Sun reaching Earth, albeit in a different form than Birkeland imagined at the end of the 19th century (Figure 7). When Birkeland returned to the University of Kristiania in autumn 1895, he began to investigate cathode rays in vacuum chambers. This new research ﬁeld soon dominated his attention. The ﬁrst experiments used ordinary glass bottles about 5 l in volume. His friend at the University Claus N. Riiber (1867– 1936) fabricated some conical tubes with an obstacle in the form of a Maltese cross. Cathode rays were ﬁrst produced in laboratories around 1850 inside tubes with most of the air pumped out. The rays appeared if the voltage difference between two metallic electrodes mounted inside the tubes was sufﬁciently high, and the gas pressure inside the tubes was sufﬁciently low, typically less than one thousandth of atmospheric pressure. “Cathode rays” emerged from the negative electrodes called cathodes. Depending on the nature and the pressure

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of residual gas molecules, cathode rays could produce spectacularly colored light as they passed through the tubes. Whenever metal plates were mounted within beams their shapes changed. Birkeland performed his ﬁrst cathode-ray experiments while he was still in Leipzig. At that time, the question of whether cathode rays were electromagnetic waves or beams of invisible particles was controversial. Birkeland’s experiments signiﬁcantly helped to resolve the issue. Since, electromagnetic wave a s are unaffected by electric and magnetic ﬁelds he studied the behavior of cathode rays in magnetic ﬁelds. Although his university laboratory was small and its equipment limited, Birkeland conducted highly advanced experiments on the inﬂuence of varying magnetic ﬁelds on electrical discharges. He demonstrated that cathode rays are guided toward magnetic poles. In February 1896, he published a paper in the Norwegian journal Elektroteknisk Tidsskrift (Vol. 8, pp. 104–110) entitled in English: “Cathode rays under the inﬂuence of strong, varying magnetic ﬁelds.” This publication was considered so important that it was soon reprinted in French, German and English. The article describes several experiments with gas discharges, test methodologies, and results. No theoretical interpretations were offered. Birkeland dealt with magnetic lenses, optical spectra, and most importantly the close resemblance between the discharges and auroral lights. His paper concludes, Cathode rays are drawn toward magnetic poles. This observation is of considerable interest in connection with the theory of auroras. . . . It may be assumed that the rays are attracted by the Earth’s magnetic ﬁeld, and in some way or other the energy is derived from the sun. This hhypothesis is supported by the fact that the yearly variations of auroras correspond with the 11-year periods of maximum solar activity.

It appeared that cathode rays were being sucked into the magnetic pole. He reasoned “Perhaps the aurora is produced in a similar way.” The main conclusion was that artiﬁcial auroral emissions could be produced by cathode rays guided by magnetic ﬁelds. Then he wrote: “The produced bands present such an analogy with the auroral bands that no doubt is possible, we see the evidence that the two phenomena are strongly related” ((Birkeland, 1896). Birkeland found that magnets could focus cathode rays to the size of a needlepoint on the inner glass wall better than an optical lens could focus visible light. The beams were so intense that if forced to move across the surface by moving the magnets, they left a track by splitting off glass particles. In this way, a Birkeland could write his name inside a glass bowl. Most probably, these were the ﬁrst letters written by magnetically guided cathode rays. In his main book, Birkeland also mentioned that he could guide visible discharges toward the glass wall by putting his ﬁnger at the outside, like modern plasma-ball toys. Birkeland mounted a cross-shaped obstacle made of aluminium in the discharge tube. He carefully studied effects of the rotating cross versus distance to

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Figure 8. Example of the ﬁrst artiﬁcial aurora produced inside a device that Birkeland called an F auroral jar, taken from Birkeland’s paper of March 1896. The picture shows his most successful simulation of artiﬁcial auroral emissions produced with cathode rays in the discharge tube. The tube was placed in a large magnet. The cathode was located in a twice-bent glass tube that merged into the container. The anode was mounted in a small sphere connected by a narrow tube to the large sphere.

the magnet. The rotation rate was slow at ﬁrst, and then more and more rapid as the distance to the ﬁeld decreased. As the separation distance lessened the image of the cross diminished to a point (Figure 9). Between 1896 and 1898, Birkeland published six papers on cathode rays in magnetic ﬁelds. He was the ﬁrst to point out (Comptes Rendus, 1896) that the particle deviation only depends on the potential difference between the electrodes when the magnetic ﬁeld is constant. Some have suggested that Birkeland got his idea about cathode-ray trajectories in a magnetic ﬁeld from Professor Poincare. ´ This idea cannot be documented. In 1898, Poincar´e published his ﬁrst paper about magnetic guiding of cathode rays and cited Birkeland’s earlier work. The same year Birkeland requested funds from the Storting to send photographic plates to high altitudes in a balloon and thus determine how deeply cathode rays penetrate the upper atmosphere. The project was not funded. Many reviews of Birkeland’s simulations assert that he ﬁrst produced an artiﬁcial aurora in his Terrella Laboratory. This is a misconception. By 1896, he was already producing artiﬁcial auroral displays in his laboratory via electric gas discharges in cathode-ray tubes. Before 1901, he was fully convinced that a natural aurora must be produced in ways that were analogous to his artiﬁcially generated ones. In 1901, he created a new class of simulations that he planned during the Haldde expedition and called terrella experiments. Between 1899 and 1910, Jørgen L. Dietrichson (1867–1911), a retired highschool headmaster, volunteered to work for Birkeland and became extremely proﬁcient in all phases of technical construction and testing. According to Olaf Devik, Dietrichson was the most enthusiastic and hard working assistant anyone

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could hope to have. “You always found him in Birkeland’s terrella laboratory. He had patience enough to evacuate the biggest vacuum camera, even if it took days. He also found more efﬁcient methods for producing cathode rays” ( (Birkeland , 1898). Based on his cathode-ray experiments, Birkeland concluded that auroral lights were caused by negatively charged corpuscles from the Sun. The “electron” had not yet been identiﬁed as an independent and fundamental unit of charge. In 1895, no one really knew what constituted electricity. During his 1896 laboratory experiments, Birkeland came to realize that cathode rays were not electromagnetic waves. They could be guided and controlled by magnets. Based on their motions in magnetic ﬁelds, he concluded that they were negatively charged. However, he did not measure the electric charge of the particles. At about the same time, Jean Perrin (1870–1942) deﬂected cathode rays with electrostatic ﬁelds and independently concluded that they consisted of negatively charged particles ((P Perrin, 1896).

Figure 9. From Birkeland’s 1896 paper “Cathode rays under the inﬂuence of strong, varying F magnetic ﬁelds”. Top picture shows the experimental set up used to illustrate “magnetic lenses”. Lower picture demonstrates the rotation of an aluminium cross as the distance to the magnet decreased.

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Historically, Joseph John Thomson (1856–1940), then leader of the Cavendish Laboratory at Cambridge University, is honored as the ﬁrst to identify the existence of “electrons” in 1897 (Phil. ( Mag. No. CCXIX, October 1897). Actually, Thomson only referred to electrons as corpuscles. In 1906, Thomson received the Nobel Prize and a Royal Title for this discovery. He soon realized that electrons are primary constituents of all elements in nature. In his original paper and in his lecture of April 30, 1898, Thomson cited Birkeland’s paper of 1896. Many have argued that German physicist Emil Wiechert (1861–1926) and Kristian Birkeland should have been recognized along with Thomson for the discovery of electrons. Had Birkeland conducted his research in France or the United Kingdom, he most certainly would have enjoyed wider recognition. On the other hand, Birkeland was pleased and proud that Thomson used some of his discoveries with cathode rays as a starting-point to demonstrate that atoms are not the smallest units in nature. I see with great satisfaction that Sir J. J. Thomson, in his classic research on the nature of cathode rays in which we ﬁnd the ﬁrst deﬁnite experimental evidence toward proving that the chemical atom is not the smallest unit in nature, has taken as his starting-point my discovery that the magnetic deviation of cathode rays depends only upon the tension between cathode and anode, if the magnetic force is constant (NAPE, p. 315).

3.3 BIRKELAND’S OFFICES AND LABORATORIES AT THE UNIVERSITY Birkeland’s ofﬁces and laboratories at the University were on the ground ﬂoor of Domus Media, to the left of the main portico. The ofﬁce ﬂoor space was only 15 square meters. From his window, he could watch trafﬁc on the Karl Johan Gate, Kristiania’s main street. The ofﬁce was crammed from ﬂoor to ceiling with papers, books, maps, and a large globe. During his ﬁrst years as professor he shared the room with his assistant Sem Sæland, whose desk was in a corner of the ofﬁce. Next to the ofﬁce was his small laboratory, also ﬁlled with electric cables and equipment. Early in 1906, Birkeland applied to the University’s Administrators for more ofﬁce and laboratory space. After Birkeland promised to cover all costs, University ofﬁcials agreed to divide a nearby lecture hall in half to provide the extra space. While some of his colleagues were dismayed, the administration recognized that Birkeland had become a valuable asset. Birkeland personally paid for the alterations and new equipment since he wanted the best money could buy. His assistants moved into the old ofﬁce. Between 1906 and 1913, he employed as many as eight technicians and scientists; of these the University only paid for two.

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Birkeland conducted electrical experiments at the University from 1895 to 1913. No contemporary laboratory was so focused on simulating electric discharges on a cosmic scale. In pioneering this ﬁeld, Birkeland developed many new inventions in vacuum technology. Although he used many different pumps, we discuss only his “mercurial pump, that worked by hydraulic pressure” (NAPE, p. 154) and a rotary mercury pump because we later consider the possibility that his health was seriously affected by chronic mercury poisoning. These pumps gave their full share of technical problems. Whenever a fore pump stopped, drawing oil vapors into the chamber, it took several days to clean it (NAPE, p. 675). The chambers also leaked. Birkeland describes one leak that “a couple of months of work failed to stop” (NAPE, p. 599). In an interview published in the Norwegian newspaper Morgenbladet he says, “It could take as much as eight days to ﬁnd a leak in the largest chamber”. With vacuum pumps available in 1901, it took more than 24 hours to reduce the pressure in a 15-litre cylinder to one thousandth of atmospheric pressure. After 1908, as pump capabilities improved, he built larger chambers. Birkeland’s new laboratory space was in the basement, under his old ofﬁce. He laid a concrete ﬂoor, built solid walls, and then cut a large hole through the ﬂoor of his old ofﬁce to add a ﬂight of stairs as a short cut to the new laboratory. Generating cathode rays required a high-voltage generator. Early in his experimental career, Birkeland used induction coils to produce high voltages from low-voltage sources. In 1907, he purchased a high-voltage generator from Thury in Geneva that delivered up to 25,000 Volts at low currents and was the most powerful generator then available for purchase. Around 1910, he hired the two Devik brothers. Karl helped Jørgen Dietrichson with terrella experiments and took over his position after Dietrichson died. Olaf was initially employed as a scientist, but he soon became Birkeland’s personal secretary, responsible for tracking his schedule and ﬁnances. After two years, the laboratory became so full of equipment that only those actually working on experiments were allowed entry. When students had questions they had to stop at the door. Birkeland’s laboratory appeared chaotic with noises, ﬂashes, and strange odors. The University inspection committee was supposed to check all rooms once a year, but they never dared to enter Birkeland’s laboratory. Karl Devik recalled that everyone had to be careful when moving about in the laboratory. Although several people suffered electric w shocks, no one was seriously injured. Everyone had to work with one hand in his pocket so that currents from electric shocks would not travel through the heart (Figure 10). During his last years, Birkeland wore a fez while working in the laboratory. This was a safety precaution and not a sign, as some have suggested, that he had converted to Islam. When asked why he used the fez, he responded it

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Figure 10. Picture of the new laboratory in the Domus Media circa 1910. The lab was full of F equipment and electric cables. The power generator on the right occupied a third of the ﬂoor space. Birkeland had a large bank of rechargeable batteries and a capacitor bank of 80 Leyden jars that were used to excite electrical discharges. He had eight cameras to photograph experiments. On the left wall hand tools were neatly mounted above the workbench. A wood stove in the corner heated the laboratory.

was because he often suffered from headaches and “it keeps my head warm.” Birkeland had lost all the hair on the top of his head by the age of 35.

3.4 TERRELLA AS ANODE EXPERIMENTS In 1901, Birkeland responded to the British critique of his auroral theory with a new set of laboratory experiments using a magnetized sphere to simulate cosmic phenomena. At ﬁrst, he referred to the device simply as a spherical electromagnet, but by 1906, he began to call it his “terrella”, a Latin word that means “little Earth”. Using a magnetized sphere in a gas discharge opened a new ﬁeld of research. For much of the next 13 years Birkeland concentrated on terrella experiments that simulated the Sun-Earth system in vacuum chambers. While these experiments represent a new technique for creating an artiﬁcial aurora in the laboratory, they also extend and clarify his earlier insight that electrical discharges reproduce phenomena found in the Earth’s upper atmosphere.

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His experiments were ingeniously simple. A small terrella placed at the center of the vacuum chamber simulated the Earth, while an electrode that emitted charged particles represented the Sun. An electric coil inside the terrella created a magnetic dipole that was scaled to control particle trajectories. The smallest terrella had an iron core 1 cm in diameter, with 240 windings of 0.4 mm copper wire insulated by silk. It drew currents between 2 and 4 Amperes from a bank of batteries below the chamber. Birkeland introduced an iron core in the third generation terrella to improve the realism of the simulated magnetic ﬁeld. For example, a 7.5 cm diameter terrella is almost 100 million times smaller than the Earth’s diameter. A similar scaling of magnetic ﬁeld strength is practically impossible. However, Birkeland found that above some threshold, luminous phenomena are not very sensitive to the magnetic ﬁeld’s intensity (Figure 11). Between 1901 and 1906, Birkeland constructed both cylindrical and spherical vacuum chambers. Many experiments used a 10 cm terrella in a 12-litre glass tube supplied with small connecters for pumping and mounting electrodes. Birkeland used various techniques to simulate the Earth’s upper atmosphere. At ﬁrst, the terrella surface was covered with phosphorescent paint that produced clearly visible emissions when struck with cathode rays. Later, the paint was replaced with a thin layer of pump oil to simulate atmospheric effects. Birkeland ran high currents through the magnetizing coil so that gas evaporated from the terrella surface. An accident in 1906 broke his cylindrical vacuum chamber. Birkeland took advantage of this opportunity to explore a radically new chamber design (NAPE, p. 553, 709). Since the curved glass of cylindrical chambers created optical distortions in photographs of his experiments, he designed a chamber with straight glass walls, like an aquarium. Birkeland’s largest “prismatic chamber” was a full cubic meter in volume. He invested proﬁts from the sale of Norsk Hydro shares into new chambers and larger terrellas. The ﬁrst prismatic chamber was 22 litres in volume with walls of plate glass 2 cm thick. Cementing the glass plates tightly together at the corners was not easy. The top and bottom of the chamber were made of bronze and all joints had to be sealed with great care. Although Birkeland mentioned pressures down to 0.0005 mm Hg inside the terrella chamber, it is likely that some experiments operated at pressures ten times higher. Pumping the air out and cleaning the chamber was a troublesome and lengthy chore, often lasting several days (NAPE, p. 676). Over ﬁve-years from 1908 to 1913, Birkeland constructed four chambers with volumes that increased from 22 to 1,000 liters. Correspondingly the thickness of the walls needed to withstand atmospheric pressure on the vacuum chambers increased from 2 to 5 cm. The vacuum chamber sat on a sturdy wooden frame. Its large ﬂat sides provided better visibility for recording experimental effects. Birkeland could

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Figure 11. Sketches demonstrating the principle underlying the terrella. Detailed technical drawF ings show the terrella and vacuum chamber and indicate how magnetic ﬁelds were produced ( (Brundtland , 1997).

thus directly observe details that had been obscured inside the small cylinders. In curved-glass chambers with walls of uneven thickness, light from the discharges distorted spatial information on the photographs. While this problem was corrected in the prismatic chamber, a new problem surfaced. During bright discharges multiple reﬂections from the glass walls degraded the photographic images (Figure 12). A cathode to emit negatively charged particles with a sufﬁciently high electric potential was situated near the chamber wall. The new 2.5 kV generator created strong discharges. The terrella itself was a thin brass sphere coated either with phosphorescent paint or oil which allowed Birkeland to see when and where electrons impacted the simulated Earth. When the magnetic ﬁeld coil w inside the sphere was turned on, electron beams illuminated the terrella’s polar regions. In some ways, Birkeland’s terrella experiments were an early demonstration of how electrons striking phosphor screens would be used to create television images half a century later. At the beginning of the 20th century, Birkeland’s experiments were the most advanced in the world (Figures 13–17 and 41). Birkeland was especially proud of his terrella experiments believing that they conﬁrmed his theory of auroral formation. After working with his largest prismatic chamber, Birkeland came to regard his experiments as far more valuable than Størmer’s orbital calculations for understanding auroral physics.

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Figure 12. Birkeland (wearing his fez) and Karl Devik working with the 36 cm diameter terrella F in the 1000 liter vacuum chamber built in 1913. This model appears on the 200 kroner Norwegian bank notes. Here Birkeland is watching a simulation of the Sun’s corona. During auroral simulations, the magnetic ﬁeld axis was tilted relative to the vertical axis. In some of these experiments the terrella rotated about its vertical axis. Terrella currents up to 40 Amps were drawn from a rechargeable battery. A capacitor bank of 80 Leyden jars is on the ﬂoor behind Birkeland. Devik is operating the new molecular vacuum pump.

Figure 13. Two regions of optical emissions, roughly 23◦ from the magnetic pole, formed to F simulate the auroral zones.

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Figure 14. Drawing of Birkeland’s 16 different discharge tubes and his box-shaped vacuum chamF bers in chronological order (Brundtland ( , 1997). This ﬁgure illustrates the range of Birkeland’s activity and imagination in the laboratory.

As discussed later, Birkeland also felt that Størmer’s calculations were of limited use until the mathematical problem was completely solved. In the early 20th century, Birkeland could not conduct measurements in space, but the next best thing was to simulate space in his laboratory. To make his experiments as realistic as possible, the terrella was supported on one end by ◦ a hinge that inclined the magnetic axis by 23.5 relative to the geographic axis. Birkeland then spent much research time documenting seasonal changes in aurora. He reported that auroral emissions differed on the evening and morning sides of the terrellas. To map variations in detail, Birkeland mounted as many as eight cameras at different viewing angles relative to the terrella (Figure 41). He also held cameras at ﬁxed positions as the terrella rotated to monitor seasonal variations. Birkeland grew in his conviction that negatively charged particles from the Sun excited auroral lights. During low-intensity discharges, it was only possible to see where cathode rays hit the terrella’s phosphorescent surface. To study electron trajectories before surface impacts, Birkeland mounted several plates in horizontal and vertical planes (NAPE, p. 81). These screens were also coated with phosphorescent paint and emitted light when struck by magnetically guided electrons. One terrella conﬁguration had eight screens with holes and slits. Although light

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Figure 15. Sketches of 10 terrellas 2–36 cm in diameter. Birkeland made the polar diameter F slightly less than the equatorial, and many experiments were performed with the magnetic axis tilted 11o relative to vertical. (a) The smallest was used to simulate zodiacal light. (b) Birkeland’s ﬁrst terrella had a diameter of 4 cm. (c) The 5.5 cm terrella was used in the ﬁrst prismatic chamber. (d) The ﬁrst terrella with an iron core simulated the magnetic ﬁeld more realistically. (e) and (f) Both are 8 cm in diameter. (g) The 10 cm terrella was used in early simulations of Saturn’s rings. (h) The 11.5 cm terrella is now on exhibit at the Norwegian Technical Museum in Oslo. (i) The 24 cm terrella was used to simulate sunspots, Saturn’s rings, and auroral light. (j) The largest terrella shown here was used in the 1,000-liter chamber. However, Birkeland does mention a larger terrella with a diameter of 70 cm. According to NAPE, p. 666, this was constructed for detailed auroral studies and would have been discussed in Volume III.

from terrellas was difﬁcult to record, Birkeland photographed auroral and solar simulations against dark backgrounds. A good deal of trial and error characterized his experiments. As a student at the University of Kristiania, Carl Størmer was deeply interested in natural sciences. He ﬁrst met Birkeland in 1899. After Birkeland heard rumors that some scientists regarded his 1895 solution of Maxwell’s equations as incorrect, he asked Størmer, who had recently completed a masters degree in mathematics, to check his derivation carefully. Størmer concluded that he could ﬁnd no mistakes and was impressed by the sophistication of Birkeland’s solution. Afterwards, Størmer often visited Birkeland’s laboratory. In 1902, when he was appointed Assistant Professor of Mathematics, Størmer asked to w join Birkeland’s team.

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During his research in Paris, Birkeland had calculated charged-particle trajectories allowed in unipolar magnetic ﬁelds. He now wished to extend the calculations to a more realistic model of the Earth’s magnetic ﬁeld. While he would never ﬁnd the time needed for this work, Størmer was just the right person for the job. Størmer carried out elaborate computations for motions of single, charged particles in dipolar magnetic ﬁelds. Together with his students Størmer spent nearly 18,000 hours on this project between 1902 and 1914. Results of these computations were published in a series of papers beginning in 1904 and are summarized in Størmer’s book The Polar Aurora (1955). The trajectory calculations were critical for interpreting laboratory and ﬁeld observations. Birkeland was delighted with the level of agreement between experimental and theoretical results. It should be pointed out that Birkeland was unable to reproduce the latitudinal shifts of the auroral zones observed after large solar disturbances. This problem remained unsolved until the 1930s when the role of the ring current during magnetic storms was recognized. After 1908, Birkeland conducted more elaborate plasma experiments, which Størmer’s calculations did not ﬁt as well. Birkeland trusted his experiments more than the calculated particle trajectories. As a result, cooperation with Størmer ceased. Later, serious scientiﬁc disagreements arose between them (Figure 16).

Figure 16. Birkeland’s terrella with auroral zones (left) and trajectories Størmer calculated for F charged particles in a dipole magnetic ﬁeld (right). Agreement between the experiments and calculations is excellent. Figure is from a 1907 paper in which Birkeland describes experiments in a cylindrical 12 litre chamber (NAPE, p. 159).

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Figure 17. Karl Devik inside the largest chamber adjusting the terrella. The top of the terrella F chamber could be opened allowing the slim assistant to climb inside to clean the walls, adjust cables and coat the terrella. Birkeland joked, “If my assistants misbehave, I put them into the universe.” The photograph gives a good sense of the chamber’s size.

Scientists eventually realized that Størmer’s calculations could not be used to interpret magnetic storms, but did describe the trajectories of cosmic rays that were discovered in 1925. Størmer’s calculations also apply to high-energy particles ejected from the Sun during great solar ﬂares.

CHAPTER 4

THE NORWEGIAN AURORAL EXPEDITIONS

Well into the modern era the aurora remained an unresolved mystery of the W natural world. Through the advocacy of arctic explorers such as Austrian Carl Weyprecht (1838–1881), a ﬁrst attempt was initiated to make systematic observations with a network of polar stations. Weyprecht sought international collaboration to make simultaneous auroral and geomagnetic-ﬁeld measurements at multiple Arctic and Antarctic locations. Such efforts could achieve much more than isolated national ventures. His suggestions were realized as the international circumpolar observations in 1882–1883, the “First Polar Year.” Eleven nations operated 14 stations, 12 in the Arctic, and 2 in the southern hemisphere but at magnetic latitudes no higher than 55◦ S. Although high-quality measurements were obtained during the First Polar Year, no publication utilized the full data collection. Scientists from particiY pating countries primarily concentrated on the analysis of their own national data. No attempt was made to synthesize the global morphology of geomagnetic storms until Birkeland’s detailed analysis of data from multiple stations appeared in 1908 and 1913. Thus, no signiﬁcant scientiﬁc discoveries in geomagnetism and auroral physics emerged from this expensive international enterprise. Sadly, the international organization disbanded as soon as scientists returned to their homes. At the time, no one imagined an international data center.

4.1 BIRKELAND’S FIRST EXPEDITIONS Birkeland’s auroral theory developed as an extension of his laboratory simulations. He recognized that to deepen his understanding of the aurora he must also make experimental measurements in the ﬁeld. Norway is probably the best place in the world for conducting such auroral studies. Its high-latitude (59◦ to 80◦ N) location, with the Gulf Stream ﬂowing along its Atlantic coast, gives access to auroral phenomena while mitigating the effects of cold arctic air masses. Birkeland organized several expeditions to the northernmost regions of Norway to collect the magnetic and auroral data needed to test his

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Figure 18. The aurora borealis has inspired people for many generations, linking the arts and F sciences.

laboratory-based theoretical understanding. His main goal was to map, describe and explain the geophysical processes that drive auroral emissions (Figure 18). From the beginning Birkeland wanted to determine whether tropospheric weather and northern lights were related. Norwegian Captain Johan Heitman (1669–1749) suggested this in his Physical Considerations of the Sun, the Air, and the Auroras, w when he quoted an old nautical proverb “Red aurora at night, sailor’s delight.” Birkeland was aware that for centuries ﬁshermen of northern Norway used auroral displays to predict the weather. He wanted to see if these folkloric predictions had a scientiﬁc basis. In applying for ﬁnancial support from the Storting, Birkeland always stressed the need for reliable weather predictions to support Norway’s ﬁshing industry. Birkeland led his ﬁrst auroral expedition in 1897 at the age of 30. He planned an observing station near 70◦ N in Finnmark, Norway’s largest and northernmost province. Soon after reaching Altafjord the team encountered an early snowstorm in which the temperature plummeted to −25◦ C. They barely survived a full day and night in the open. Birkeland later reported, “The storm increased with frightful rapidity. All had frostbitten noses and chins, but nothing could be done. We could see nothing and could not walk. Everyone had to get into his sleeping bag as quickly as possible.” They returned to their starting point 31 hours later.

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b

c

Figure 19. (a) Map of Finnmark with Haldde and Talvik marked. (b) Defense Meteorological F Satellite Program (DMSP) image showing locations of major Scandinavian cities relative to the quiet-time auroral oval. Kafjord ˚ is more than 10◦ (1,100 km) north of Oslo. (c) Haldde station.

One of his student assistants, Bjørn Helland-Hansen (1877–1957) who aspired to become a surgeon, froze the tips of his ﬁngers. After a medical examination, he was sent to the nearest hospital, more than a day’s journey away. Unfortunately, it was necessary to amputate some of his ﬁngertips to the ﬁrst or second joints. Thus, Bjørn Helland-Hansen had to abandon his hopes of becoming a surgeon. Later, working with Professor Fridtjof Nansen, he became a world-renown oceanographer. Birkeland felt a keen responsibility for the safety of student assistants who followed him on his hazardous expeditions. After two weeks in which they made only one auroral observation, he terminated the expedition. Although this ﬁrst effort was unsuccessful, he did not give up. During the following summer he returned to Finnmark where he selected two mountaintops, Haldde and Talvik near Kafjord, ˚ as sites for future investigations (Figure 19). In the fall of 1899, Birkeland returned to Kafjord ˚ to continue his auroral and geomagnetic observations. Since K˚a˚ fjord is in the center of the auroral zone the

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Figure 20. Drawing of aurora over K˚a˚ fjord by Louis Bavalet (1839). F

Sun stays below the horizon in December and January, allowing up to 16 hours a day to observe auroral displays. This small copper mining town is partly populated by Lapps whose livelihood depends mainly on herding reindeer. The mine, established in 1826, was the most northerly industrial enterprise in Europe. Kafjord ˚ soon became the largest town in Finnmark. When Birkeland arrived, the director of the copper mine was Anders Quale, who often invited Observatory personnel to his home where they enjoyed fresh food, warm baths, and female companionship. Birkeland’s choice of Kafjord ˚ was inﬂuenced by a well-known French expedition in the winter of 1838–1839 headed by Paul Gaimard (1796–1859) ((Knutsen and Prosti, 2002). The French team built ﬁve small observatory huts in which they installed instruments to make auroral, geomagnetic ﬁeld, meteorology, and astronomical measurements. Although they collected a wealth of data, few were ever analyzed. They conducted simultaneous, visual, auroral observations from two sites separated by about 50 km. On this basis, the team members estimated that normal auroral emission heights are near 150 km. However, they believed that height estimates of 1,000 km made by Jean Jacques Dorto`u` s de Marian (1678–1771) a century before were correct and never reported their own triangulation results. From today’s perspective, the most important heritage of Gaimard’s expedition may well be the auroral drawings of Louis Bavalet, an artist who accompanied the expedition. A sample of his work from January 1839 is shown in Figure 20. K˚a˚ fjord was also the site of one of the Norwegian stations of the First Polar Year and a German auroral expedition in 1892.

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Figure 21. Aurora over the Haldde station. This is probably the ﬁrst photograph of an aurora. F

On September 16, 1898, about a month before his second expedition, Birkeland published his ﬁrst popular auroral article entitled “Sunspots and Auroras: A Message from the Sun” in the newspaper Verdens r Gang. This marked the ﬁrst presentation of his auroral theory to a general audience. It was also studied in Sweden and Denmark. Adam Paulsen (1833–1907), Director of the Danish Meteorological Institute who was active in auroral and geomagnetic research, wrote a polite response presenting an alternate perspective. His letter of September 30, 1898 provides a candid view of the scientiﬁc thinking of the time. Paulsen clearly accepted that cathode rays were the immediate cause of auroral light, but he believed that the Sun could only be a remote cause by providing the energy to drive electric currents between the polar and equatorial regions of the upper atmosphere. By chance, I recently received a copy of the September 16 issue of the Norwegian newspaper Verdens r Gang in which you published a long article: Sunspots and Auroras, with the subtitle “A Message from the Sun.” You explain your new auroral theory based on cathode rays coming directly from the Sun and guided for great distances by the magnetic ﬁeld. Please allow me to present my objections to your theory. My hypothesis is that cathode rays are produced in the upper atmosphere by electric currents that ﬂow from equator to the pole during daytime. A large negative voltage in the polar region, due to these currents, radiates cathode rays. This equator-to-pole current explains observed, diurnal variations of magnetic needles. My concept agrees with the ideas of the Swedish scientist Arrhenius1 who claims that the current is due to the Sunlight. In this way, the auroras are indirect results of the solar radiation, but the source is in the atmosphere. I do not understand how your hypothesis can explain diurnal variations of the northern lights, that have local-time maxima near 10 PM and minima near 10 AM. The Sun’s radiation of cathode rays cannot depend on the rotation of the Earth. The diurnal variation in northern lights must depend on the solar zenith angle.

1

Svante A. Arrhenius (1859–1927) was awarded the Nobel Prize in Chemistry in 1903 for his work on the theory of electrolytic dissociation. Several papers published by Arrhenius in the early years of the 20th century suggest that he came to substantial agreement with Birkeland’s hhypothesis for a solar source of auroral displays.

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Just before we observe auroras, magnetic needles ﬂuctuate. Currents in the atmosphere must be strong to generate cathode rays. I cannot understand how cathode rays, if they come from the Sun, can inﬂuence the Earth magnetic ﬁeld rays before they enter the atmosphere. How does your hhypothesis explain currents in the auroras? Our observations in Greenland indicate the presence of atmospheric electric currents when we observed auroras, at least drapery auroras. We both refer to cathode rays being sucked toward the Earth. For me the word “sucked” means absorbed in the atmosphere. The atmosphere cannot attract cathode rays. Thus, my use of the word has a completely different meaning than in your hypothesis about cathode rays and magnetic ﬁelds. I would appreciate your comments Yours sincerely, Y Adam Paulsen

After the expedition of 1902–1903 Paulsen came to accept Birkeland’s view of a solar source for auroral emissions. In preparation for his second expedition during the winter of 1899–1900, Birkeland built the world’s ﬁrst permanent auroral observatory on the summit of Haldde Mountain, a rocky peak with steep slopes on three sides. To triangulate auroral heights he built a second station about 3.4 kilometres away on Talvik Mountain. Haldde and Talvik are on the west side of the Altafjord, with peaks more than 900 metres high. Measurement cycles were coordinated via telephone line. Reindeer pulled sleds ﬁlled with 40 tons of building material, instruments, and supplies to the summits, a formidable task. The walls of both observatories were of ﬁeldstone nearly a meter thick. The roofs were layered timbers of a sturdy Norwegian design. Insufﬁcient time was allocated to prepare for wintering over in the extreme arctic environment. A powerful snowstorm in August delayed construction for three weeks, so the observatories were not completed until mid-October. Birkeland reported that several times during winter storms wind speeds exceeded 46 m/s (∼100 mph), the highest their anemometer could measure (NAPE, p. 26). The lowest temperature during the expedition was −34◦ C. The Haldde Observatory had a ﬂat-roof viewing platform that was free of obstructions. Under clear conditions the ﬁeld-of-view extended for more than 1,000 kilometers from horizon to horizon. Birkeland was deeply proud of his small, sturdy observatories at perfect sites for studying the high-latitude sky with views unhampered by artiﬁcial lights, trees, or buildings. However, extreme weather conditions on mountaintops only 2,200 kilometers from the North Pole were far worse than those found in Kafjord. ˚ Even in retrospect, their isolation and vulnerability in wintering at these stations is almost unimaginable. Among his many objectives, Birkeland wanted to test the suggestion of a Finnish professor Karl Selim Lemstrøm (1838–1904) that northern lights

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rise from high, sharp mountaintops and extend down to the ground. From his observatories this was easily tested. If Lemstrøm were correct, Birkeland should see auroral light coming from below the Haldde platform. Other basic uncertainties about the heights of auroral emissions could only be resolved with two or more well-separated ground stations. Since the distance between his two stations was only 3.4 kilometers, Birkeland must have believed that auroral emissions came from deep in the atmosphere. In time he became increasingly convinced that auroral displays occur at heights above the inﬂuence of winds. He certainly never saw auroral lights below cloud level, much less down to the treetops. Both observatories were well equipped with instruments from Germany. Otto Topfer, ¨ the best instrument manufacturer in Europe, fabricated the exquisite magnetometers with perfectly turned brass ﬁttings, quartz, and steel needles. They were housed in special interior rooms built on pillars driven into the solid ground. No objects made of magnetic material, such as iron, could be used in recording houses because they would affect magnetic readings; only brass, copper, and ceramic objects were used. The magnetometers measured the strength and direction of the Earth’s magnetic ﬁeld by recording its two horizontal and one vertical components. The most important measurements were of changes in the three ﬁeld components that occur during geomagnetically active periods.

Figure 22. Drawing showing the principle of the magnetometer used for measuring the Earth’s F magnetic ﬁeld. The tiny magnet hangs by a quartz thread, as does the mirror shown to the right. The light source is on the left. The magnet responds to changes in the Earth’s magnetic ﬁeld caused by electric currents in the upper atmosphere. The mirror reﬂected the light beam onto a roll of photographic paper that scrolled by a clock device at a steady rate. The light-beam creates continuous lines on the photographic paper if no variations in the ﬁeld occurred. During magnetic disturbances the small magnet moved in response to the variations in the Earth’s ﬁeld, and large deviations were recorded. The observatories had self-registering barometers, thermometers, and hhydrometers, as well as instruments for measuring the electric conductivity of the atmosphere. Birkeland wrote: “The worst trouble was the repeated breaking of our telephone-wires. At ﬁrst the telephone wires between the two summits were hung upon poles in the usual manner; but that proved to be useless” (NAPE, p. 8).

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The heart of the magnetometers was a tiny magnet hung at the bottom of a quartz thread. The magnet’s orientation changed to stay in alignment with the Earth’s magnetic ﬁeld as it responded to electric currents in the upper atmosphere. Continuous recordings were made automatically using a narrow beam of light from an oil lamp. The light was focused with a lens and beamed directly at a mirror in front of the magnet. The mirror reﬂected the beam onto a long roll of photographic paper that scrolled by a clock device at a steady pace, while the light beam created continuous lines on the photographic paper. If the w magnetic ﬁeld were quiet, the lines were straight. During magnetic disturbances the magnet ﬂuctuated with variations in the Earth’s ﬁeld, and the lines were erratic. Strong magnetic ﬂuctuations were later compared with northern lights seen dancing across the sky. The recording paper was developed each morning in a small darkroom, and the magnetometer traces were compared with the log of visual auroral observations (Figure 22). By the end of October, less than two weeks after the observatory opened, all the instruments were calibrated and ready for use. At this time, Birkeland began his career as an inventor designing devices to make life more comfortable on the isolated mountaintops. His ﬁrst invention was a pump with a series of pipes connected to the stove to keep the bunks warm throughout the cold nights. After this he constructed a battery-powered alarm system to alert the group that instrument readings were due, thus minimizing exposure to the harsh environment. Birkeland was pleased and fortunate to have Sem Sæland, then 25, as his assistant. Like Birkeland, Sæland belonged to the Liberal party and strongly opposed the Union with Sweden. He had narrowly avoided a jail sentence for hissing the Swedish King Oscar II and Crown Prince Gustav during a visit to Kristiania in 1897. He was forced to resign from the Student Union, and some professors argued that he should be expelled from the University. Sæland then spent a year teaching in Iceland before returning to ﬁnish his studies in mathematics and physics. Birkeland asked him to operate the Talvik mountain station. He was well suited for that task, temperamentally calm and experienced with instruments. The station was signiﬁcantly smaller than the Haldde Observatory, with room for only two people. In November 1899, Birkeland wrote a letter from Haldde to Elling Holst at the University, describing life at the observatory as an adventure in a castle with a fairytale f landscape. “Our postman, a sturdy little Finnmark man, comes regularly with mail twice a week.” They followed ﬁxed timetables for both days and nights. In addition to checking the magnetometers and observing aurora, they made meteorological measurements of temperature, wind speeds, air conductivity, Earth currents, and cloud conditions. Because he had suffered from insomnia since his student days Birkeland usually did the nightly instrument readings.

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Days at the observatory were busy taking readings, mending instruments, keeping the inside temperature warm, and maintaining the water supply. Snow was blown off the mountaintop so they often had to descend to the valley for ice. According to later reports by Birkeland and Sæland, life was not easy. However, despite the difﬁcult working conditions at Haldde and Talvik there was rarely any tension within the group. Birkeland was an active, interesting, and inspiring leader, even to the youngest member, Elisar Boye, 22, a Latin scholar. They often discussed basic auroral and geomagnetic ﬁeld concepts and soon became close friends. Birkeland always enjoyed the company of intelligent students and enthusiastic graduates. To build and equip the observatories at Haldde and Talvik and operate them for one year, Birkeland had requested 12,000 Norwegian kroner from the Storting, nearly three times his annual salary. Birkeland also borrowed some instruments from the University’s Astronomical Observatory. On the recommendation of the Ministry for Church and Education, the Storting granted him the requested sum. They realized that Birkeland was a brilliant researcher and looked favorably on the chance to have a Norwegian scientist resolve the auroral mystery. Fiscally, the expedition was not well planned. No one appreciated the high cost of constructing houses at 70◦ N on the tops of 900 m mountains. Final budget for the expedition was more than three times the Storting’s allocation. Birkeland simply did not think about expenses while he was actively engaged on a campaign. For him the only objective was to carry out all required observations. Unfortunately, he also failed to keep proper accounts. Just a month after work began, he made his ﬁrst request to the Storting for additional funding; three more followed in the ﬁrst year. In matters of bookkeeping and formal paperwork, for either the University or the government, Birkeland was not well organized. He usually recorded expenses on scraps of paper that were often lost. In later years, his trusted assistant Olaf Devik always checked and controlled invoices. A story is still told at the University that when a ﬁnancial ofﬁcer asked Birkeland for an invoice, he replied: “Why? I remember the sum.” Birkeland even forgot to submit a ﬁnal accounting for the expedition, later creating a signiﬁcant problem when he had to justify all expenditures to the special committee of the Storting. When they received the ﬁnal tally for the expedition, the oversight committee concluded that they had never seen such poor bookkeeping. The ﬁnal sum for the Haldde expedition was 38,297 kroner, more than three times his ﬁrst estimate. Many members of the Storting were as upset with his poor planning as the ﬁnal cost. Birkeland was held personally responsible for the ﬁasco. However, while his reputation was poor in ﬁnancial matters, the government appreciated the quality of his scientiﬁc work.

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Figure 23. Title page of Birkeland’s second book, printed in 1901, shows a picture of the Haldde F and Talvik Observatories drawn by Elisar Boye.

On March 16, 1900, a terrible snow avalanche occurred near the Haldde Observatory. Two people, including Birkeland’s young assistant Boye and Richard Lange, a local sea captain who often visited the Observatory, lost their lives. Two others were swept under in the avalanche but managed to extricate themselves. All team members were insured for 10,000 kroner, double the yearly salary for a senior professor, but Birkeland was devastated by Boye’s death. He wrote a long letter to his parents explaining in detail the circumstances surrounding the tragedy. He wrote, “I too have been mourning his death . . . . I enjoyed his youthful energy that made everything go at full speed.” Boye’s drawings of the Haldde and Talvik stations graced the cover of Birkeland’s 1901 book about the expedition (Figures 23 and 24). The tragic loss of a young student was much discussed at the University. Some older professors felt that Birkeland was too young to be in charge of such an expensive expedition. They criticized “the enthusiastic physicist” whose lack of ﬁnancial control and foolhardy schemes led to the death of a talented student. Although Birkeland drew his share of criticism, he was also greatly admired

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Figure 24. Student photograph of Elisar Boye. F

by the more forward-looking faculty members. As for Birkeland himself, “The image of Boye will always stay with me.” When Birkeland and his team returned from Haldde, he employed Sem Sæland as his research assistant at the University to analyze all the data. Together they worked long days, seldom distracted from their task. In October 1900 Birkeland published “The Auroral Expeditions,” his ﬁrst brief description of Within a year of the expethe Haldde expedition, in Elektroteknisk Tidsskrift. W dition’s conclusion he published a much more detailed account: L’Expedition Norvegienne de 1899–1900 pour l’etude des Auroras Boreales: Resultats des Recherches Magnetiques. In it Birkeland discussed the origin of terrestrial magnetism and the causes of magnetic storms. The analysis focused on data from northern Norway, but did include some simultaneous magnetograms from the Potsdam Observatory in Germany. Little mention is made of auroral lights. Birkeland fervently hoped that his new research would be understood and thus enhance Norway’s reputation within the scientiﬁc community. In placing Elisar Boye’s drawing of the two stations with a Norwegian ﬂag ﬂying above them, Birkeland risked a public reprimand from the Swedish government and perhaps the loss of a few readers across the border. Most of the book’s printing costs were borne by the Nansen Foundation. The Norwegian audience for such a research report was very small. For this reason, Birkeland wrote several popular articles for Norwegian newspapers about all they had learned during the expedition. He also gave lectures at the University and the Norwegian Academy. Hoping for a wide international audience, Birkeland chose to write

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the report in French. A report written in English might have been more widely read. However, Birkeland did not speak English well and had fewer ties with British than French scientists. After the book was published in 1901, Norwegian newspapers celebrated Birkeland as a brave sportsman and brilliant scientist on their front pages under headlines such as “Riddle of the Aurora Solved.” Throughout Europe, Birkeland was recognized as a scientist of unusual quality. Geophysical scientists around the world studied his new measurements and discussed his explanations. The book’s only unfavorable reviews came from England and were deeply disappointing to Birkeland. The Royal Society of London was regarded as the world’s most prestigious center of advanced scientiﬁc research. Election to the Royal Society ranked among the highest honors that could be bestowed upon a scientist. However, the Society itself elected new members. As the book was published in French, it received only limited reviews. In particular, the Philosophical Transactions of The Royal Society attacked the book and gave it a low rating. The basis of this negative review was a remark by Lord Kelvin published in the Proceedings of the Royal Society (1892). Kelvin believed that the Sun could not affect the Earth’s magnetic ﬁeld and that apparent correlations between solar and geomagnetic activity were illusory. He regarded interplanetary space as devoid of matter. Few British scientists were prepared to take public issue with Kelvin’s conclusion. Certainly some must have doubted that except for visible light and gravity the Earth was totally isolated in space. For his part, Birkeland realized that he would need new and more cogent results to turn the Royal Society. He thus started planning a more ambitious expedition that would compel British colleagues to reconsider the causes of magnetic disturbances and auroral lights. Results of the 1899–1900 Norwegian Polar Expedition (1901) contain the ﬁrst determination of the global pattern of electric currents in the polar region based on ground magnetic ﬁeld measurements. Birkeland argued that terrestrial phenomena associated with auroral emissions and electric currents are best described in a coordinate system that is ﬁxed with respect to the Sun. The Earth simply rotates under the auroral and current patterns. His map clearly shows a “two-cell” pattern of ionospheric currents that converge over the polar region. Modern ground-based observations of the magnetic ﬁeld and satellite-based measurements of electric ﬁelds conﬁrm the existence of a two-cell pattern of plasma convection in the polar region. During periods of high geomagnetic activity plasma ﬂows at high speed (1–2 km/s) across the polar cap away from the Sun. The two-cell pattern is critical for understanding how electromagnetic energy from the Sun disturbs the high-latitude ionosphere. Conﬁrmation of the two-cell pattern in satellite measurements lends credibility to Birkeland’s prophetic research (Figure 25).

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Figure 25. Current patterns viewed from above the North Pole. Birkeland called the drawn curves F “lines of currents at midnight, Greenwich time.” Global ionospheric currents are represented in a coordinate system oriented with respect to the Sun. In a 24-hour period, the Earth rotates under the current pattern, as indicated by the curved lines ((Birkeland, 1901).

4.2 ARCTIC EXPEDITION OF 1902–1903 While analyzing data from Haldde, Birkeland realized that to understand magnetic storms and auroral emissions more deeply he would need simultaneous magnetic and optical observations from multiple stations. At least one of the stations should be located well north of the auroral zone, the others spread out in longitude along it. For the ﬁrst time, signiﬁcant portions of the polar cap and the auroral zone would be mapped continuously using identical instruments. The expedition would exploit Birkeland’s global view of geomagnetic disturbances.

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Figure 26. Map showing locations of the four stations established in 1902 to chart variations in F the Earth’s magnetic ﬁeld. Stations were about 1,000 km apart.

In 1901, Birkeland began to plan the logistics of an expedition with four stations about 1,000 kilometres apart. Requirements of the 1902–1903 expedition are well documented in his publications of 1908 and 1913. To save time and money he proposed using existing buildings as living quarters. Birkeland had learned enough during the 1899–1900 campaign that he no longer needed to place observatories on mountaintops. His four stations were at: (1) K˚a˚ fjord, in Finnmark, near the Haldde Observatory, (2) Dyrafjord, Iceland, (3) Axeløen in the Svalbard Archipelago, and (4) Matotchkin Schar on Novaya Zemlya, Russia. These stations and the distances between them are marked on Birkeland’s original map (Figure 26). Notations on the map emphasize that they were The Norwegian Stations, even though three of them were not in Norway. These sites required scientists with experience living in harsh arctic environments, so each team had to include at least one scientist who had wintered at an arctic station. To gain international support for his 1902–1903 expedition, Birkeland sent appeals to many magnetic observatories seeking cooperation. He also wrote

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two circular letters to the world community of scientists and published a note in T Terrestrial Magnetism and Electricity, June, p. 81, 1902, stating: It would be of the greatest importance, necessity, I would say, to obtain simultaneous observations from most parts of the Earth . . . . The task is to determine the connection existing between earthmagnetic perturbations, boreal lights and cirrus-clouds. . . . To obtain a happy solution of this task, it is absolutely necessary to get the requisite facts from the largest number of points as widely as possible over the whole earth. . . .

He included instructions on how to obtain high-quality data and ﬁxed times for their registration. Birkeland’s second circular gave more detailed information about the selected observing days. He concluded, “I am willing to refund any expense incurred in connection with it” (Terr. T Magn. and Atm. Electr., June 1903, p. 74 and NAPE, p. 37). Based on his analysis of Haldde and Potsdam magnetometer measurements, Birkeland requested either copies or the loan of standard and rapid-run magnetic recordings for 30 speciﬁc days scattered throughout the winter months. Apparently he received no British or German measurements from the Southern Hemisphere. His two-volume report on the expedition, published in 1908 and 1913, shows no Antarctic data. Birkeland also wrote extensively about Earth currents, but we do not discuss them here. To garner ﬁnancial support for his third expedition, Birkeland submitted a detailed plan to the Storting in July 1901, requesting 38,000 kroner, a substantial amount of money for a poor country. The proposal again linked auroral and geomagnetic studies with meteorology and weather predictions. He hoped that the Storting had noted the international attention given to his scientiﬁcally successful Haldde expedition. With his application, Birkeland included six letters of recommendation from some of the world’s most famous geophysicists including the directors of: the Prussian Meteorological Institute, the Central Meteorological Bureau of France, the Central Physical Observatory in St. Petersburg, the Potsdam Observatory, the Educational Bureau in Hamburg, and the German Naval Observatory. No letter of recommendation came from a British observatory. All the letters stressed the expedition’s importance for simultaneous mapping of geomagnetic ﬁelds and the aurora at multiple high-latitude stations. Strong support from well-known European scientists demonstrated that Birkeland had proposed a signiﬁcant mission. Of great importance to the Storting were the recommendations of the University’s faculty and President, together with letters from the directors of the Norwegian Astronomical Observatory and Norwegian Meteorological Institute. The Ministry for Church and Education, which was responsible for all research, reacted positively. Letters also came from famous Norwegians such as Fridtjof Nansen expressing their warmest approval for the expedition. “Because

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of our country’s location Norway has a duty to participate, a duty that cannot be evaded.” Then, and in the years ahead, Gunnar Knudsen (1848–1928) supported Birkeland. He was a member of the Liberal party who joined the government as Minister of Finance and Agriculture in 1902 and was elected Prime Minister in 1908. Early on he discovered Birkeland’s talent as a researcher and they came to know each other well. Knudsen was a wealthy man who owned a large farm and shipyard. He gave a speech in the Storting on the merits of Birkeland’s expedition. Thanks to his support the government recommended the Storting allocate funds for the campaign. However, there was substantial disagreement among the Storting’s 150 members. Overspending during the expedition of 1899–1900 was a recent memory. In his proposal Birkeland included an option for cooperating with foreign scientists. This meant he could conduct the expedition without further grants from the Norwegian State. He concluded, “I hesitate to do this because I regard the investigations to be of such importance that I prefer them to be Norwegian.” To his friend Vilhelm Bjerknes, he wrote: “We Norwegians shall force the Swedes to respect us; we shall teach them a lesson.” Favorably disposed members of Storting regarded it as shameful for Birkeland to seek sponsors abroad. They argued that the expedition would have an impact on the entire world. Independent of other considerations, Norway needed to promote its political interests in the Artic, particularly in the ﬁshing industry. To this end, better weather forecasts would be of great value. After long debate the Storting voted 90 to 21 to give Birkeland 20,000 kroner for the expedition. Secretary of Agriculture Knudsen, disappointed by the decreased budget, gave Birkeland a generous contribution of 6,000 kroner. Within a week two other wealthy Norwegians followed Knudsen’s example. One was the owner and editor of Norway’s most widely read newspaper, Aftenposten, which published several articles about the project. The other donor was the w richest man in Kristiania, Johan J. Fabricus. Thus, Birkeland received 18,000 kroner from individuals for a mission whose purpose very few really understood. Birkeland was delighted and wrote grateful acknowledgements for the grants supporting his auroral expedition in the Aftenposten. In some private papers, Birkeland wrote, “The remainder, I furnished myself.” Current estimates are that he had to use nearly 6,000 kroner of his own money to balance the ﬁnal budget. By that time Birkeland was also receiving ﬁnancial remunerations from his industrial ventures. When the expedition teams returned to Kristiania, every one agreed that the expedition had been a great success. However, no money remained to hire assistants for data reduction. Birkeland applied to the Storting for data-analysis funding, but was rejected.

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4.2.1 The Four Stations All four magnetic observatories used identical, prefabricated houses for making routine measurements and establishing absolute calibrations. Existing buildings served as living quarters. Food, fuel, and other supplies for a full year were carried to the two northern stations. Station leaders and their assistants drew salaries of 100 and 75 kroner per month, respectively. Each observatory was equipped with: 1. Standard magnetic instruments from Otto Tøpfer in Germany 2. Universal instruments for absolute calibrations 3. Electrometers from Elster and Geitel to measure electric conductivity of air 4. Instruments to measure Earth currents 5. Meteorological instruments to measure air pressure, temperature, and wind velocity 6. Spare parts, tools, log books, recording paper, cameras, and chemicals 7. Bifocals and other devices to measure distances, directions, speeds 8. Five sled dogs for Axeløen and Matotchkin Schar 9. Coal and wood for heating at Axeløen and Matotchkin Schar. The ﬁrst new observatory was placed near the church in K˚a˚ fjord, along the banks of the Altafjord, and the prefabricated houses were assembled. The nearby Haldde and Talvik Observatories were only used for calibrations. Richard Krekling, a recent science graduate, was appointed station leader; Olaf Egenæs, an electrical engineer, was selected as a permanent staff member. Sem Sæland, Richard Krekling, and Olaf Egenæs set out for K˚a˚ fjord with their equipment on July 10, 1902, and arrived on the 17th. Birkeland had planned to control the entire campaign personally from K˚a˚ fjord, but when he visited the station in September, he was so pleased with the way Krekling and Egenæs were conducting regular measurements that he decided to maintain expedition headquarters at the University of Kristiania. This allowed him more time for laboratory experiments. Twice during the winter he visited the K˚a˚ fjord station. Throughout his life, Birkeland quickly changed plans in response to new information. One of their magnetometers was later placed in a mine, 100 meters under the mountain. Dyrafjord is in northern Iceland, about 350 km northeast of Reykjavik. Birkeland chose the site because of its proximity to an old Norwegian whaling station. Dyrafjord’s location 75◦ west of Novaya Zemlya ensured good longitudinal coverage. Because Sem Sæland had spent a year in Dyrafjord he was selected to be the station leader. Based on his previous experience with local workers in Iceland, Sæland was the only leader without a permanent assistant.

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Figure 27. Dwelling house at Axeløen Station (NAPE, p. 27). F

As discussed below, Sæland was unexpectedly called upon to help establish the Novaya Zemlya station. Because of this diversion and encounters with bad weather on his way to Iceland, his station opened near the end of October, a month after the others. The station at Axeløen on Svalbard was near a primitive hunting station in the southern part of West Spitzbergen, roughly 10 km south of Longyearbyen, the present main center on Svalbard. At about 78◦ N, the Sun remains well below the horizon for four months a year. The Axeløen station included ﬁve buildings. The team lived with three hunters in a house that was 4.5 m long and 2.5 m wide, with one-meter thick walls of stone and wood, and one small window. In addition, the team had a warehouse of similar size that also served as a privy. The ship used for transport froze in the bay just outside the station where the hunters used it for storage. The station has now been renovated and w stands as a memorial to the ﬁrst permanent Norwegian research expedition on Svalbard (Figure 27). Nils Russeltvedt (1875–1946) an employee of the Norwegian Meteorological Institute, served as the Axeløen station leader. Although he still needed two years to complete his degree in meteorology, Professor Mohn recommended him for the job. Russeltvedt visited the K˚a˚ fjord station for a few days to receive instructions on mounting and operating the instruments. The Axeløen team sailed from Tromsø near the end of July in the company of polar explorer, Johan Hagerup. Hagerup’s son Harald was the team’s electrician and Russeltvedt’s assistant. Birkeland felt that Russeltvedt and Hagerup made an excellent team. Russeltvedt wrote a long article for Aftenposten about their experiences during the year at Axeløen entitled: The Birkeland Research Station on Spitzbergen; from a Winter Over. One year on Svalbard taught him how little we know about natural forces in the polar regions. He describes their small hut, its ﬁve inhabitants, how they made water from snow and maintained

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personal hygiene. He felt fortunate to have a chair made of whalebones. His photography dark room was a locker. Every Sunday Russeltvedt wrote a summary of the events of the past week; team members read and commented on his notes. The prefabricated houses for magnetic ﬁeld measurements and calibrations were located about 100 meters from the living quarters, and a shelter for meteorological observations was nearby. However, it blew down two days after being installed. They soon learned to dig into the permafrost and weigh down the roof with heavy stones. It was often too cold and windy to stay outside for auroral observations. Therefore, they mounted a big barrel in which an observer could sit while monitoring auroral displays. Several team members remained active hunters and by the end of the expedition, they had accumulated the fur of 13 polar bears, 42 foxes, and 130 seals, plus 700 kilograms of eiderdown. They sailed back to Norway on July 25, 1903 and reached Kristiania in early August. For the fourth station, the governor of Archangel gave Birkeland permission to send a team of four scientists to Matotchkin Schar on Novaya Zemlya Island, affording them all possible assistance. In 1877, Russia had established national control by sending many Samoyed people to colonize the island. Matotchkin Schar’s location ﬁt well into Birkeland’s plan. Alexander Borisoff, a well-known Russian artist, owned a furnished house there and lent it to the team at no cost. He even offered them the use of his food supplies. Hans Riddervold, the leader of the Novaya Zemlya team, was then 26 years old. His degree was in physics, but he had very little experience with geophysical measurements. He, too, spent a week with Krekling at the K˚a˚ fjord station before traveling to Russia. A professor in zoology at the University recommended Hans Thomas Schaaning and Johan Koren as assistants for Riddervold. Both had lived in polar environments and were experienced hunters. They told Birkeland they could speak Russian. As they really only knew a few words, their claim was exaggerated. Birkeland met the crew in Archangel, where the Swedish/Norwegian Consul Falsen graciously invited them to stay in his home. Rimski Korsakoff, Archangel’s governor, kindly arranged free transportation on the steamer Wlademir and gave them access to a supply depot intended for shipwrecked sailors. A trip between Archangel and Novaya Zemlya normally took seven days. The crew met two Samoyeds from Novaya Zemlya who helped set up the station. The Samoyeds warned them about the remoteness of the island as well as its ferocious and changeable weather. People living on Novaya Zemlya dressed in traditional Samoyed clothes made of reindeer skin. A group picture taken in July 1902 shows Birkeland with his three assistants and one of the Samoyeds. Birkeland was wearing a regular business suit; the others were dressed in fur from head to toe (Figure 28).

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Figure 28. Birkeland with his three assistants and one of the Samoyeds at Archangel in August F 1902.

Shortly after this picture was taken, Birkeland was bitten by a rabid dog. The local doctor strongly recommended that he go to the Pasteur Institute in Moscow for immediate treatment. Thus, Birkeland never visited the Matotchkin Schar station. Before leaving Archangel, he cabled Sæland to come at once to Matotchkin Schar and make sure that all instruments were installed and operating correctly. Sæland was then at K˚a˚ fjord helping Krekling set up his station. Sæland traveled to Novaya Zemlya to inspect the station, but remained there for only three days. He was lucky to get back to the mainland. The day after he left, ice covered the main part of the island. Had he stayed an extra day he would have been trapped for the winter on the island. This unexpected trip delayed the opening of the Iceland station. At the Pasteur Institute in Moscow, Birkeland received inoculations that were extremely unpleasant. He spent more than a month recuperating at the Institute before returning to Norway. Although Birkeland found this ﬁrst stay in a hospital a very boring experience, it did provide plenty of time to think and plan for the future. He now realized how difﬁcult and unpredictable planning big expeditions could be. Aftenposten even carried an article about Birkeland’s being bitten by the rabid dog. Teams at the two northernmost stations experienced severe weather with T temperatures falling below −40◦ C for days on end and continuously intense

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Figure 29. Map of Kafjord, F ˚ Matotchkin Schar, and Archangel with distances and travel routes marked.

winds. Because of Boye’s accidental death during the previous expedition, all team members chosen by Birkeland had Arctic experience. As an added precaution, they were given further instructions about the dangerous environment, advised on what to eat and drink, and warned to avoid travel during bad weather. Hunting, especially for polar bears, was a necessary part of daily life to replenish fresh food supplies. Scientists at Axeløen and Matotchkin Schar returned with skins and fur, along with samples of rare Arctic birds, eggs, and polar foxes which they sold to museums in Europe. Both Riddervold and Schaaning wrote articles and books about their stay at Matotchkin Schar. Riddervold called Novaya Zemlya “an island of the dead ”. A Samoyed couple and their child lived close to their station. In January the husband died, and Riddervold’s assistant had to make a cofﬁn for him in which he remained for four months before burial became possible. During these months, the widow and child lived at the Norwegian station (Figure 30).

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Figure 30. Photograph inside the Novaja Zemlya station. F

Riddervold‘s article about their stay at Novaja Zemlya describes conditions: On February 22, a remarkable thing happened. The barometer suddenly fell to the lowest level of the year. The whole mass of ice in the strait, which had been fast since November and was very thick, went drifting away. Soon afterwards we had open water everywhere. A few days after the water again became cold and the ice became fast as before. . . . We saw many polar bears. One day we had three on our doorstep. Bear meat was a welcome addition to our larder. . . . On July 21, at 2 in the morning, the Wlademir steamed into the harbor, and the expedition broke up hastily. On August 3 we reached Archangel ((Riddervold, 1961).

Birkeland was particularly pleased with the assistance rendered by his Russian hosts. Consequently he wrote a formal letter to the King of Sweden requesting that he award four medals to honor four Russian ofﬁcials. The awards were granted (Figure 31). 4.2.2 Birkeland’s Main Research Contribution There is a three-year hiatus in Birkeland’s geophysical research while he established Norsk Hydro as the industrial center for manufacturing nitrogen-based fertilizers. In early July 1906, Birkeland resigned as Norsk Hydro’s technical director and sold most of his shares in the company, gaining the ﬁnancial freedom to hire assistants, and equip a modern laboratory. He still had income from his salaries as senior professor and technical consultant to Norsk Hydro. Now he also had time to analyze the vast quantities of data from the third expedition.

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Figure 31. A brief excerpt from Birkeland’s letter to the King requesting medals for the Russian F ofﬁcials who had helped him.

In addition to measurements of his four stations, he received more than 600 magnetograms from 23 other stations around the world, mostly at mid-latitudes. In addition to Sæland, who was paid by the university, Birkeland hired several other assistants to help with data analysis. The two most important were Lars Vegard (1880–1963) and Ole Andres Krogness (1886–1934), both graduates of his physics course. Birkeland dedicated himself to writing his major scientiﬁc contribution “The Norwegian Aurora Polaris Expedition 1902–1903” a monumental two-volume monograph published separately in 1908 and 1913 by Aschehoug, a Norwegian printing company. Nearly a century later, it is still considered a classic of geomagnetic analysis. Birkeland consciously chose aurora polaris rather than the more common aurora borealis in the title to highlight the fact that auroral phenomena are characteristic of both hemispheres. While most of his earlier publications were written in French, this treatise was published in English. In the preface Birkeland relates that he wrote the main part in Norwegian, while Miss Jessie Muir translated it into English. Because of his lack of proﬁciency in English, this arrangement saved time better dedicated to research. When the ﬁrst 400-page volume was published in a gold-embossed calfskin binding, Birkeland considered it a personal triumph. A more handsome treatise

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Figure 32. Title page of The Norwegian Aurora Polaris Expedition 1902–1903. F

had never been printed in Norway (Figure 32). The Norwegian Aurora Polaris Expedition 1902–1903 is unusual in cosmic physics because it includes descriptions of laboratory practices, diagnostic methods and experiments, research projects, theoretical physics, observational results, and travel adventures. Observations of visible auroral displays were his main diagnostic tools. Photographs of terrella experiments show his laboratory simulations of aurora and other cosmic phenomena that he describes in detail. He also discusses the expedition, characteristics of the four stations, and his reasons for choosing their sites. Copies of the book were distributed to the Scandinavian, German, French, and British press and to scientists around the world. It was read with greatest interest in the United States and Japan. To a large extent British scientists ignored it, refusing to consider his well-documented conclusions. Because the printer only expected to sell a few hundred books, Birkeland covered most of the cost. The second volume of nearly 450 pages was published in a similar binding in 1913. Again Birkeland was proud of his ﬁnal results, and he wrote (NAPE Preface, Bind II, 1913), “We have arrived at results that seem to us so valuable that they have fully rewarded us for the exertions and personal sacriﬁces that the work has cost.” The two volumes together include 42 plates and weigh more than 10 pounds. The quality of the data was excellent, largely because

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of his capable and dedicated assistants. The printing company later combined Volumes I and II into a single book. V Originally he planned a third volume but he never ﬁnished it. Birkeland also intended to write a monograph on possible connections between the aurora, magnetic storms, and weather phenomena, particularly high-altitude clouds, based on his meteorological observations. That, too, was never written. As the years passed Birkeland began to doubt his early belief that cirrus clouds were connected with auroral lights. The Norwegian Aurora Polaris Expedition 1902–1903 is signiﬁcantly different from contemporary physics textbooks. It combines theoretical equations, laboratory experiments, and ﬁeld observations with descriptions of the organizational planning for the expeditions. Birkeland also presents his methods for handling and interpreting data. He begins with a detailed discussion of his three auroral expeditions in Finnmark, the observing stations, his battles with bad weather, and the problems of undertaking pioneering research in remote locations. This introduction is well illustrated with original photographs taken at the different sites. The quality of the magnetograms from the various stations is impressive (Figures 34 and 36). The prefaces for the two volumes present the scientiﬁc background for Birkeland’s research work and describe its practical implementation. Repeatedly, he emphasizes that his conclusions are primarily based on laboratory simulations. In the following sections, we show that Birkeland’s conclusions were also quite extraordinary. Another remarkable aspect of the book was Birkeland’s analysis of magnetic recordings for 1902–1903 acquired at 27 stations. Never before had anyone utilized such widespread coverage. In contrast, only 14 stations were available at the time of the First Polar Year 1882–1883. With such a large number of stations Birkeland was able to construct a global pattern of magnetic ﬁeld changes during disturbances. In all he studied several hundred individual magnetic disturbances, triggering scientiﬁc interest in worldwide geomagnetic observations. The Norwegian Aurora Polaris Expedition 1902–1903 received much attention in Norway where some newspapers described Birkeland as a world pioneer in auroral research. Today it is practically impossible to obtain a copy, and it could easily cost $1,000. The 850-page treatise remains a scientiﬁc landmark, documenting Birkeland’s theoretical work, his laboratory simulations and ﬁeld observations of auroras, geomagnetic disturbances, solar dynamics, and other cosmic phenomena. Considering his early work with Maxwell’s equations, it is not surprising that Birkeland was convinced that electric currents ﬂowing in the upper atmosphere must cause the magnetic disturbances. He was still uncertain about the cause of the intense currents. In his analysis, the direction and intensity of the

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Figure 33. Illustration of Birkeland’s method of estimating height and direction of upper atmoF sphere currents by coordinating measurements from two observatories. Arrows indicate current directions.

currents responsible for the geomagnetic disturbances observed at each station were marked on a world map. His original sketch shows that the magnetic perturbations are at right angles to the causative currents as in the map on page 72. The largest arrows for the event mark the origin of a magnetic disturbance. Birkeland found many cases in which a strong east–west current, now called an “electrojet”, ﬂowed above or very near the station recording the greatest magnetic disturbance. From the viewpoint of potential theory, it is always possible to obtain a two-dimensional closed current system ﬂowing on a sphere concentric with the Earth, as long as ground level magnetic perturbations have no local current sources. The resultant current pattern depends on the height of the spherical shell. Patterns look alike as long as the current-layer’s height is much less than the Earth’s radius. Birkeland also noted that the geomagnetic ﬁeld undergoes regular oscillations with periods of a few seconds to a few minutes. He called these oscillations pulsations. Geomagnetic pulsations remain a productive ﬁeld in space research (Figure 35). 4.3 CLASSIFICATION OF GEOMAGNETIC DISTURBANCES Birkeland’s analysis of hundreds of magnetic records from around the world led him to divide geomagnetic disturbances into three categories with well-deﬁned

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Figure 34. T F Typical magnetic recordings from 22 stations. More than 30 such diagrams are included in NAPE. Note that the main disturbances are observed at Birkeland’s four stations.

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Figure 35. Birkeland mapped the directions of the magnetic disturbance vectors on world maps. F

characteristics: 1. Polar elementary storms, positive and negative 2. Equatorial perturbations, positive and negative 3. Cyclo-median storms. The terms “positive and negative” distinguish between situations in which the north–south horizontal component of Earth’s main magnetic ﬁeld increased or decreased at polar or equatorial latitudes. He wrote, “On some days there were no signiﬁcant variations at all.” One of Birkeland’s great scientiﬁc strengths was a keen eye for seeing characteristic patterns in data and rapidly drawing hhypotheses that a more detailed analysis would then conﬁrm or reject. He had a remarkable ability to see parallels between laboratory experiments and ﬁeld measurements. He often pointed out, “To a large extent I based my conclusions on simulation experiments in the laboratory.” 4.3.1 Polar Elementary Storms “These two principal systems, the negative and the positive polar perturbations, rarely occur alone. As a rule they occur simultaneously, but in different districts. It appears that, on the whole, they are grouped in the same manner with respect to the sun.” In Birkeland’s view these two types of disturbances had “a certain genetic connection” with one another. Polar elementary storms, which are closely connected with the generation of auroras, were ﬁrst identiﬁed during the Haldde expedition. Consequently, further understanding demanded coordinated observations to complement measurements from a single station. The original descriptions by Birkeland of these three classes of elementary distur-

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Figure 36. T F Typical polar elementary disturbances, today called substorms, as observed at Birkeland’s stations.

bances are also quoted in the famous textbook Geomagnetism (Chapman and Bartels, 1940, pp. 317–326). Polar elementary storms are now referred to as “polar substorms” although Birkeland’s nomenclature appears more logical. In the 1960s, Sydney Chapman (1888–1970) was asked to name the disturbance types, so “substorm” prevailed (Figure 36). Birkeland also found large differences in magnetic disturbances recorded at high-latitude stations, especially at magnetic latitudes from 60◦ to 75◦ , where w auroral lights occur most frequently. He became convinced that the magnetic disturbances must be due to localized current sources that he approximated as line currents. Spacecraft measurements show that these currents ﬂow at heights between 100 and 130 km above the ground. We now refer to these currents as auroral electrojets. 4.3.2 Equatorial Perturbations Positive and negative magnetic disturbances at low latitudes correspond to the initial and main phases of magnetic storms. According to Birkeland (NAPE, pp. 439–440): The deﬂections in horizontal intensity always increase at the beginning of the storm rather rapidly and to a certain height, after which the perturbing forces remain more or less constant in strength for a long period (say up to 6 hours). In the horizontal-intensity curve, there are always a number of very characteristic variations, that are found again at all the stations situated in low and medium latitudes, and these variations appear at any rate nearly simultaneously all over the globe. The equatorial perturbations often come as precursors of polar storms; and indeed we have never met with perturbations of this kind with which there have not, within the same period, been polar storms (NAPE, p. 79).

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The negative equatorial storms are more powerful in the region of the equator, where the perturbing forces in horizontal intensity are negative. The forces that occur in the negative equatorial storms are also considerably greater than those found in the positive. Among our observations we have found only examples of negative equatorial storms, which occur simultaneously with polar storms, and it is perhaps doubtful whether this type of perturbation on the whole can occur alone. We have insufﬁcient material, however, for the formation of any well-founded opinion on the matter (NAPE, p. 447).

Two objectives of the 1902–1903 Polar Expedition were to identify periodicities in the occurrence rates of polar storms and to determine the time delay between the meridional passage of sunspots and the onset of magnetic disturbances. Birkeland felt quite certain that the Sun was the source of great storms. However, data from his stations showed that disturbances recurred on average in 29.1 days, more than a day longer than expected based on existing knowledge of the Sun’s 28-day rotation. This puzzled Birkeland. Was it possible the difference was simply an artifact of his analysis? He knew of no geophysical cause. It was clear that some storms were associated with the meridional passage of large sunspot groups. In these cases, a storm began on average 1.6 days later, corresponding to an average speed of 1,080 km/s for the “agent” causing the disturbance. According to Birkeland, these observations showed “that the appearance of large sunspot groups does not take place as regularly as the principal maxima of storminess” and “very often large storms are not accompanied by any sunspots at all.” These facts led Birkeland to conclude, “Regarding the connection between sunspots and storminess it seems improbable that sunspots can be the direct cause of magnetic storms. . . . The results suggest that sunspots and magnetic storms are both manifestations of the same primary cause.” Birkeland felt (NAPE, p. 526, 614) that the main source had to emit corpuscles continuously, even when the region faced away from Earth. He used the phrase “pencil rays” to describe the likely source of geomagnetic storms. Birkeland was also aware that the Sun’s dipolar magnetic ﬁeld would inhibit the emission of electric corpuscles at equatorial latitudes. However, charged particles from polar regions would be “bent somewhat toward the magnetic equator of the sun” (NAPE, p. 526). He also found higher rates of “storminess” near equinoxes. Birkeland’s 1902–1903 observations were conducted near sunspot minimum when high-speed streams from coronal holes may have caused periodic storms. We now know that Birkeland had observed seasonal and latitudinal effects of the Sun’s rotation, which is slower at mid-latitudes than at the equator. 4.3.3 Cyclo-Median Perturbations The third type of magnetic perturbations occurs primarily at middle latitudes on the Earth’s dayside. Birkeland called them “Cyclo-Median Perturbations”,

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because they result from closed (or circular) current circuits of limited size not far above the Earth. Viewed from above in the northern hemisphere, currents of the equivalent circuit ﬂow in a counter-clockwise direction. In present terminology, this type of disturbance is associated with the occurrence of solar ﬂares. Intense ultraviolet light increases the ionospheric density and thus the amount of current the ionosphere can carry. Unlike auroral currents, the new ionization is not created by the impact of energetic charged particles. Birkeland was ﬁrst to recognize this distinctive type of variation in the Earth’s magnetic ﬁeld. 4.3.4 Field-Aligned Currents in Space Birkeland’s most enduring contribution to auroral physics was his recognition that ﬁeld-aligned currents are needed to couple auroral phenomena in the upper atmosphere to interplanetary space. This conclusion has profound and farreaching signiﬁcance for understanding the origin of geomagnetic currents. The most common method used to detect the presence of currents in the polar ionosphere is through the magnetic perturbations they produce on the ground. Birkeland understood that these currents could derive from two possible sources NAPE; Section 36: N With regard to the further course of the current, there are two possibilities. (1) The entire current W system belongs to the Earth. The current-lines . . . ﬂow at some height above the Earth. (2) The current is maintained by a constant supply of electricity from without. The currents will consist principally of vertical portions. At some distance from the Earth’s surface, the current from above will turn off and continue for some time in an almost horizontal direction, and than either once more leave the Earth, or become partially absorbed by the atmosphere.

That he favored the explanation of polar elementary storms driven by ﬁeldaligned currents is clear from NAPE; Section 92: We consider it to be beyond doubt that the powerful storms in the northern regions, . . . that we have called elementary, are due to the action of electric currents near the auroral zone.

Strong horizontal electric currents ﬂowing overhead in the auroral zone produce the magnetic ﬁeld disturbances of polar elementary storms. These horizontal currents connect to ﬁeld-aligned currents that ﬂow into and out of the ionosphere near the equatorward and poleward boundaries of the auroral current. Birkeland’s approximate current system for a negative polar elementary storm is shown in Figure 37. He estimated that the currents were up to a million Amperes in strength and ﬂowed at altitudes above 100 km. Present estimated values for the auroral electrojet are in the 0.3 to 5 million Ampere range. Given the intensity of currents needed to explain observed magnetic disturbances,

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Figure 37. Original ﬁeld-aligned current systems suggested by Birkeland in 1908. This is FigF ure 50 in Vol. 1, NAPE; p. 105. On the Cause of Magnetic Storms and the Origin of Terrestrial Magnetism.

Birkeland concluded that only the Sun could provide the electromagnetic forces needed to power magnetic storms and auroral emissions. Based on his terrella experiments and Størmer’s calculations, Birkeland proposed the ﬁeld-aligned current system shown in Figure 37 (NAPE, p. 105). However, the two current systems he initially mentioned became a source of controversy that continued for more than half a century. Sydney Chapman and his colleagues vigorously promoted Birkeland’s ﬁrst suggestion, that the

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current system was conﬁned to the vicinity of the Earth. Hannes Alfv´en (1908–1986) and his co-workers emphasized Birkeland’s ﬁeld-aligned current h hypothesis. The existence of ﬁeld-aligned currents was disputed vigorously among scientists for 50 years. Indeed, Chapman and his co-workers constructed “equivalent” current patterns, closing completely within the ionosphere, that explained almost all ground magnetic measurements. However, a quirk of nature actually makes it impossible using only ground-based magnetic ﬁeld measurements, to judge unambiguously between current systems that contain ﬁeld-aligned segments and those that completely close in the ionosphere ((Fukushima, 1969, 1994). Inferring the real current pattern required magnetic ﬁeld measurement in space. Absolute proof for the existence of ﬁeld-aligned currents could only come from satellite measurements taken above the ionosphere. In crossing ﬁeld-aligned currents, magnetometers on satellites routinely detect characteristic magnetic disturbances. The present technique is limited by the fact that it takes multiple spacecraft to measure three-dimensional currents fully. The ﬁrst direct evidence for the existence of ﬁeld-aligned currents was found in 1966 measurements by a U.S. Navy TRIAD satellite. A year later the International Union for Geomagnetism and Aeronomy unanimously declared that they should be called “Birkeland currents”. Many observations of Birkeland currents and their association with magnetic disturbances have been reported in recent decades. Patterns of such large-scale currents deduced from satellite measurements are supported by observations of electric ﬁelds and auroral particles. Birkeland currents are critical for understanding electrical coupling between the magnetosphere and the auroral ionosphere. Global intensities can reach 10 million Amperes. The energy that they dissipate in the upper atmosphere can greatly exceed that deposited by electrons and ions that cause visible aurora displays. In Volume II of NAPE and in several other publications, Birkeland argued that electromagnetic forces might be as important as gravity for understanding our solar system. In this, he was the ﬁrst to stress a critical role for electromagnetic forces in the cosmos. 4.4 THE PERMANENT STATION AT HALDDE MOUNTAIN Birkeland found that correlations between auroral lights and magnetic disturbances were far more complex than anticipated. Distinct, narrow auroral forms could appear in the absence of measurable magnetic activity. Only when auroral displays covered large areas of the sky did he ﬁnd good correlations. As a practical remedy Birkeland concluded that Norway needed a permanent observatory to make continuous records of auroral lights, magnetic ﬁeld disturbances and atmospheric parameters. However, he was so busy with other projects that he

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did not draft the ﬁrst application until 1910. In May of that year, Birkeland and his assistant Ole A. Krogness spent a month at Haldde trying to map the effects of Halley’s comet as it passed close to Earth. During the visit he became even more determined to exploit the unique research opportunities afforded by the Haldde Observatory. In the summer of 1910, Birkeland asked the Storting for 30,000 Norwegian kroner to build a more comfortable and larger station on Haldde Mountain. The new station would house four families and even accept small groups of visiting scientists. Birkeland sought support to operate the station for at least two solar cycles, 22 years. The research would focus on weather forecasting to improve severe storm warnings. He concluded: Such a station will be a gold mine for new scientiﬁc discoveries and very important for the poor province Finnmark. It may well act as a gleaming tower for the rest of Europe—the most important of all geophysical observatories in the whole world—and demonstrate that Norway is a cultured nation.

The Secretary for Education and Church, Mr. Mohn thought that it would be impossible to ﬁnd qualiﬁed personnel for such a remote station. Birkeland was upset by this objection and replied: As long as I am alive, I guarantee that the station will be manned by qualiﬁed researchers even if it takes more than four hours to return to the village. When our nation uses that much money on research, then nothing—intellectual or corporal—must stop us from choosing the absolute best (Devik archive).

Fortunately, the Director of the Meteorological Institute supported him, as did most of his colleagues at the University. Sem Sæland, as the ﬁrst Rector of the New Technical University in Trondheim, wrote a strong letter of support. The Storting appropriated funds in 1911. Comfortable living quarters for employees were linked to the observatory by a tunnel and were ready for occupancy in the summer of 1912. A picture of the new station at Haldde, about 900 m above sea level, at 70◦ N is shown in Figure 38. Like the ﬁrst observatory, seen in the background, it too had one-meter thick stonewalls so that winter winds would not blow it away. Its interior wooden walls were well insulated. Ole A. Krogness was appointed the Observatory’s ﬁrst director in the summer of 1912; he and his wife moved to Haldde in October. Both came from musical families, and he had refused to accept the offer unless a piano was brought to the station. Four men labored for six hours carrying their piano up the mountainside. Three other technicians and engineers joined the Krogness family. In the summer of 1915, Olaf Devik accepted the position of assistant director, responsible for expediting reliable weather prediction for Northern Norway. Between 1915

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Figure 38. Picture of the new Haldde station built in 1912. F

and 1919, ten adults and seven children lived at the Haldde Observatory (Figure 38). Birkeland considered the Haldde Station almost personal property and visited it several times after the formal opening. No one was employed at Haldde without his permission. If the staff experienced ﬁnancial problems that the government did not cover, he always made personal contributions. To a large extent, he also directed the main research projects. His written advice to both Krogness and Devik was: “Use your own eyes, capacity and sense and let nobody tell you what you should look for. If you work hard and conscientiously, your research will become your hobby.” Although scientiﬁc research had been conducted at remote outposts before, few were more remote and isolated than Haldde. In 1917, the Storting decided to move most of the Haldde activities to Tromsø, and in 1927, the Tromsø Auroral Observatory opened. T Birkeland was initially convinced that solar phenomena were linked to tropospheric weather and climate as well as to geomagnetic disturbances, and he conducted meteorological observations during all of his expeditions. Work summarized in Volume I indicated that he was particularly interested in possible correlations between the formation of cirrus clouds and geomagnetic storms. Birkeland had convinced the government to support the permanent Haldde Observatory in part because he believed that upper atmosphere observations would help predict severe weather in northern Norway. Vilhelm Bjerknes, a ffather of modern meteorology and a member of the committee, supported the observatory. Birkeland worked hard to ﬁnd “sun-weather relations”, but eventually came to realize that no convincing observational results conﬁrmed this h hypothesis.

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British scientists were particularly critical of Birkeland’s work and largely ignored his terrella simulations. At the beginning of the 20th century they found it impossible to believe that the Sun was the ultimate source of auroral and geomagnetic activity. Schuster (1911) disagreed with Birkeland’s interpretation of magnetic storms. He argued that beams of electrons from the Sun would break apart in their transit to Earth because of mutual repulsion. Although Birkeland often focused on negatively charged particles because of their roles in exciting auroral emissions, he stated on a number of occasions that, “Corpuscular beams from the Sun contain both electrons and positive ions”. Birkeland also wrote: “From a physical point of view it is most probable that solar rays are neither negative nor positive rays, but of both kinds.” Schuster overlooked this distinction. In 1919, Lindemann offered the constructive suggestion that magnetic storms are most likely produced by a stream of charged particles of opposite signs in equal numbers, a stream of neutral ionized gas. We now call this streaming gas the solar wind. Had Lindemann read Birkeland’s papers, he would have realized that he was reiterating an earlier suggestion. Birkeland was aware of British objections against the direct arrival of charged particles from the Sun. However, he found the results of his terrella experiments so exciting and compelling that he stood by his initial hypothesis calling for direct impacts by solar particles. The eminent English mathematician Sydney Chapman (1888–1970) was elected to the Royal Society at age 31. After turning his attention to geomagnetism Chapman introduced a number of important theoretical concepts in contemporary magnetospheric and ionospheric physics. His vantage point was distinctly different from Birkeland’s. Instead of focusing on individual events, Chapman tried to ﬁnd an average morphology of magnetic disturbances from their statistical means. Thus, his method excludes strong individual ﬂuctuations. In addition, he approximated the corresponding overhead currents as ﬂowing horizontally in the ionosphere. From this perspective he diligently denounced Birkeland’s work and ideas. Chapman and his collaborators E. H. Vestine (1906–1968), Masahisa Sugiura (1925), and Syun-Ichi Akasofu (1930) V strictly followed the equivalent-current system method. We refer to Chapman and his followers as the British School, while w those who followed Birkeland’s method we call the Scandinavian School. The British School was convinced that the average characteristics of magnetic disturbances did not differ substantially from those of very large storms. By the 1930s Chapman’s thinking dominated magnetic storm studies (Figure 39). In his book Geomagnetism (pp. 317–326), Chapman states: “Birkeland seems not to have realized that a magnetic storm is a unitary phenomenon, going

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Figure 39. Three key scientists of the ionospheric current debate: Kristian Birkeland (left), F Sydney Chapman (center), and Hannes Alfv´e´ n (right).

through regular phases. . . . He split up the perturbations artiﬁcially into small portions that ought to be considered together”. In this assertion, Chapman certainly overlooked Birkeland’s statements about “generic connections” in storms. Vestine and Chapman (1938) also wrote a paper arguing that Birkeland’s current V system was inadequate and Chapman’s superior, even though their proposed current systems were only “equivalent” or “hypothetical.” Unfortunately, their paper misrepresented the role of Birkeland’s current system in magnetic disturbances, but this was not discovered until many years later. In 1994, Professor Naoshi Fukushima (1920–2003) of the University of Tokyo revealed a serious ﬂaw in Vestine and Chapman’s comparison of their S D current system with their interpretation of Birkeland’s. According to Vestine and Chapman, “In the case of Birkeland’s model a good ﬁt with observations near the auroral zone implies a poor ﬁt with observations near the centre of the zone, and vice versa. . . . There, Birkeland’s current system should be discarded as unsatisfactory. . . . Even a drastic modiﬁcation of the model will not result in a great improvement” (Vestine V and Chapman, 1938). Their opinion reﬂected an intellectual bias against the very concept of ﬁeld-aligned currents. However, the critical point is that they incorrectly represented Birkeland’s ﬁeld-aligned currents in their drawing of his proposed system, and their conclusions were without merit. Fukushima (1994) showed that they should have compared the two proposed current systems with the same electrojet conﬁguration along the auroral zone. But the damage was done, and Birkeland’s explanation of magnetic storms was neglected for another 30 years (Figure 40).

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Figure 40. Atmospheric current systems developed by Chapman (C) and Birkeland (A) (top). F Illustrations Vestine and Chapman used in order to reject Birkeland’s model (middle). Two-cell polar current pattern similar to the one that Birkeland proposed (bottom). ((Fukushima, 1994).

When the organizing committee for the 1967 Birkeland Symposium asked Sydney Chapman to give the opening address, he selected as the title “Historical Introduction to Aurora and Magnetic Storms.” In his review, Chapman emphasized the importance of Birkeland’s pioneering work in studying magnetic storms. Chapman states, “In science it is our good custom to appreciate the true

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discoveries and enlightening stimulus provide by great men, rather than to dwell on their misconceptions.” However, he was unable to abide by this custom. He went on to say “The apparently unshakable hold, on Birkeland’s mind, of his basic but invalid conception of intense electron beams, mingled error inextricably with truth in the presentation of his ideas and experiments on aurora and magnetic storms.” The participants were shocked, and in the following discussions showed that they did not support his conclusions. Subsequently Chapman recanted saying, “I feel I unwisely neglected the valuable opportunity afforded by Birkeland’s great collection of records of individual storms, available from before the time when I began to interest myself in these phenomena. Storms should be discussed both statistically and individually. Disbelief in Birkeland’s theory of electron streams obscured the realization of the value of his beautifully presented data collection, though I appreciated that they had enabled me to make very important progress in our knowledge of storm morphology”. Basically Chapman remained tied to the view that a vacuum usually surrounds the Earth, while Birkeland believed that interplanetary space is ﬁlled by charged particles. Birkeland is known internationally for auroral and magnetic storm research. His work on the Sun, interplanetary space and his concept of stars as mass sources for interstellar space, while more fascinating, are markedly less known. Many of his ideas were based upon laboratory experiments designed to model phenomena in space. Birkeland had a unique intuition and a special talent for technical work. His approach later proved fruitful both in generating new ideas and for understanding basic physical processes. In the ﬁrst Kristian Birkeland Lecture of the Norwegian Academy of Science and Letters given at the University of Oslo in September 1987, Hannes Alfv´e´ n provided an excellent survey of Birkeland’s worldview. During his later years Birkeland became intrigued by phenomena in distant space. Much of his work then centered on ejecting electric corpuscles from central bodies in the universe. He applied his basic idea to the Sun and to comets, and he also considered Saturn’s rings to be formed by matter ﬂying past the planet. He came to think that electromagnetic forces are as important as gravity in space. The Sun and the stars acted as centers for generating these ﬁelds and as sources of matter in interplanetary and interstellar space. Birkeland wrote, “According to our manner of looking at the matter, every star in the universe would be the seat and ﬁeld of activity of electric forces of a strength no one could imagine. . . . It seems to be a natural consequence of our point of view to assume that the whole space is ﬁlled with electrons and ﬂying ions of all kinds. We have assumed that each stellar system in evolution throws off electric corpuscles into space” (NAPE, p. 720).

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In view of later developments, this line of reasoning is most fascinating. Birkeland held the view that all stars were gas sources for “empty space”. Today we know that a static stellar atmosphere is a singular case; the atmosphere must expand into a supersonic stellar wind. However, in a high-pressure environment, like a dense interstellar cloud, the external pressure may become so large that there is an inﬂow of gas to some stars very similar to the accretion during star formation. Birkeland wrote in 1913, “One of the most peculiar features of my cosmogony hypothesis is that space is assumed to be ﬁlled with ﬂying atoms and corpuscles of all kinds in such density that the aggregate mass of heavenly bodies would be only a small fraction of the aggregate mass of the ﬂying atoms.” Unfortunately, Birkeland’s postulate concerning physical connections between interplanetary and interstellar space was long overlooked. A consequence of continuous outﬂow of electrons and ions from the Sun is that the universe is ﬁlled with ionized gas. Birkeland estimated the density of a gas of one solar mass distributed uniformly in a spherical volume whose radius is the distance to the closest star, Alpha Centauri. He showed that such a gas would have negligible consequences for both the radiation observed in near space and on “the resistance to the motion of the heavenly bodies.” Therefore, he concluded that we should not exclude the possibility that the mass in our universe between stars is considerably greater than the mass in the stars (NAPE, p. 721). The degree of aesthetical enjoyment Birkeland experienced in basic research is clear from his claim: “I have carried out a long series of experimental investigations with a magnetic globe in a large vacuum-box intended for electric discharges. . . . Those who will go through the whole labyrinth of experiments . . . cannot but be attracted by their scientiﬁc beauty; and in the end they will see that great difﬁculties have resolved themselves into a surprising clearness” ((Birkeland, 1913). The Scandinavian School that found physical merit in Birkeland’s work included eminent scientists from the United States and Japan. Their leader was Professor Hannes Alfv´e´ n (1908–1989) of The Royal Institute of Technology, Stockholm and the 1971 Nobel Laureate in Physics who became Birkeland’s unyielding champion in opposition to Chapman. For many years Alfv´e´ n argued strongly for the necessity of ﬁeld-aligned electric currents for understanding geomagnetic disturbances. Chapman regarded them as superﬂuous. Their controversy took many years to resolve. Despite the arguments, auroral and geomagnetic research made great progress prior to the advent of direct space exploration. Sounding-rocket experiments clearly established the connection between particle precipitation and auroral luminosity (cf. Egeland et al., 1983, Cosmical Geophysics).

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Hannes Alfv´e´ n greatly admired Birkeland’s work. In his 1987 paper he wrote: However, it was not until Birkeland performed his terrella experiment, that it became obvious that an electric discharge around a terrella produces luminous rings around the poles. Birkeland identiﬁed these rings with the auroral zones. This identiﬁcation has turned out to be correct. It is analogous to Newton’s conclusion about the apple and the Moon. Hence it is fair to say that whereas Newton—Apple—Moon is essential in understanding the mechanical forces of the universe, it follows that Birkeland—Terrella—Aurora is just as essential in the electromagnetic effects. This analogy actually goes further. Newton’s Principia is, of course, an epoch-making treatise. However, today it is almost impossible to read because of its obsolete mathematical language. The best way to arrive at a clear and simple understanding of what Newton did is to consider the anecdote about the apple and the moon. Similarly, today Birkeland’s discovery should be linked to the plasma formation, but still his epoch-making results are essentially condensed in the terrella-aurora conclusion.

While editor of the JJournal of Geophysical Research and chairman of the Department of Space Physics and Astronomy at Rice University, Professor Alexander J. Dessler played a pivotal role in resolving the ﬁeld-aligned-current controversy. He has written several papers expressing his admiration for Birkeland’s contributions. A short excerpt from his 1988 paper reads: Birkeland was the complete scientist. He was simultaneously a theorist, a laboratory experimentalist, and a ﬁeld experimentalist, and he was exceptional in each area. He was one of the few physicists of his time to master Maxwell’s electromagnetic theory. In the laboratory, Birkeland was without peer. He assembled laboratory equipment that, at that time, was of unprecedented size and complexity, and he could make them work. He also mounted large-scale and widespread ﬁeld expeditions to collect information and quantitative data. These expeditions included the construction of small but sturdy mountaintop observatories in the northernmost province of Norway. Birkeland’s central interest was the aurora, but his auroral research expanded into what is now space plasma physics. He offered plasma-physics explanations of the aurora, as well as a number of other phenomena such as the rings of Saturn, the formation of comet tails, and even the creation of the solar system. He directed every technique he could think of toward obtaining an answer to a problem. Thus, he would attack a single problem with ﬁeld observations, laboratory experiments, and an analytic theory. His work stands as an example of dedicated scientiﬁc craftsmanship.

CHAPTER 5

THE UNIVERSE IN A VACUUM CHAMBER

5.1 TERRELLA AS CATHODE EXPERIMENTS As early as 1896, Birkeland made the important assumption that the Sun radiates cathode rays as well as light. Several of his publications suggest that most of the mass in the universe is not in the stars and the planets, but in what was then called “empty space”. The emission of corpuscles from the Sun was a central theme in all Birkeland’s scientiﬁc work. A century ago, he estimated the density of interplanetary space to be about eight particles per cubic centimeter. This is remarkably close to the average density of the solar wind as observed in the space age. He writes, “My point of view is different from all earlier published theories” (NAPE, p. 569). The basis for his stance is that, “my theories are supported by simulations in the terrella laboratory”. From the beginning of his auroral studies in 1895, Birkeland became increasingly fascinated with the Sun. He assumed that sunspots were the main source of solar cathode rays. In the summer of 1899, he published a 175-page treatise called Recherches sur les taches du soleil et leur origin, his ﬁrst work on the Sun and sunspots. He collected data from three solar observatories during the years 1858–1864, 1880–1886, and 1890–1896. The University gave him a small research grant to pay ﬁve students to help him organize the observations. One of his main hypotheses to explain solar-activity variations invoked a tidal effect from the position of the outer planets Jupiter and Saturn with respect to the Sun. The same year he published another paper on the Sun called Sur la constitution du Soleil. A few years later, his thoughts on the causes of solar disturbances evolved in a different direction. He concluded, “there are still many unknown forces at the sun, but electromagnetic forces must be important.” 5.2 SUNSPOTS AND THE SOLAR MAGNETIC FIELD In 1908, Birkeland initiated a series of terrella experiments related to the Sun and its magnetic ﬁeld. He came to the opinion that sunspots were the foot points for intense electric discharges. By mounting Leyden jars in the electric circuit, he obtained long rays of light that bent in magnetic ﬁelds. Cathode rays from the simulated sunspots could be guided by the magnetic ﬁeld, clearly

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Figure 41. Birkeland’s terrella experiment, with eight cameras overlooking eight screens to map F electron trajectories accurately.

demonstrating that they are charged particles. In his most advanced experiments, Birkeland mounted eight screens between the simulated Sun and the Earth. Birkeland also took excellent pictures of the solar corona during an eclipse. Distinctive forms seen in the corona led him to conclude that the Sun had a magnetic ﬁeld. He states the basis for his conclusion, “The radiation from the terrella strongly resemble the sun’s corona.” If the terrella Sun did not have a magnetic ﬁeld, the electric discharges scattered all over the sphere. Only when a strong magnetic ﬁeld was applied to his artiﬁcial Sun did the spots converge near the equator. Thus, he concluded that the Sun must have a large magnetic ﬁeld, at least 100 times stronger than that of the Earth by his estimates. Birkeland therefore thought it logical that all rotating bodies in the universe have magnetic ﬁelds. After several years of conducting detailed laboratory experiments, he wrote two papers in Comptes Rendus w where he further developed his theory regarding the magnetic ﬁeld, namely Sur le magn´e´ tisme gen´eral ´ du Soleil and Remarques sur les essais faits par Halepour determiner le magn´e´ tisme general du Soleil. Birkeland’s outlook expanded after his success with auroral simulations. He suggested that the 11-year sunspot cycle must be related to the Sun’s magnetic

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ﬁeld, which derives from complex internal electric currents. He understood that the dipolar magnetic ﬁeld of the Sun would inhibit the emission of electric corpuscles at equatorial latitudes. Charged particles ﬂowing outward at polar latitudes would bend toward the equatorial plane in the Sun’s magnetic ﬁeld (NAPE, p. 526). He ordered a 70-cm rotating terrella made of magnetizable steel so he could test his theories in the laboratory (NAPE, p. 666). To study corpuscles from the Sun, he changed the polarity of the electrodes and used the magnetized sphere in the vacuum chamber as the cathode. The cathode terrella began emitting charged particles. He could now simulate a wide range of phenomena, such as the occurrence and motions of sunspots, the solar corona with and without total eclipses, Saturn’s rings, comet tails, and zodiacal light. When the terrella was not magnetized, discharges occurred all over the surface. When the sphere was magnetized, a thin layer of luminous matter appeared, and corpuscles from the emitting globe formed rings in the equatorial plane. As the magnetic ﬁeld strengthened, the spots moved closer to the equator similar to the observed distribution of sunspots during solar maximum years when magnetic disturbances and auroral displays are most intense. Birkeland w thus conﬁrmed that the Sun must have a strong, but variable, magnetic ﬁeld. He also identiﬁed two belts of discharges on the emitting spherical cathode, one above and one below the equator, at latitudes that increased as the magnetization decreased (Figure 42). Birkeland also felt that matter ejected from the Sun was the source of magnetic disturbances on the Earth. Furthermore, in the absence of a one-to-one correlation, he discovered that not all solar disturbances caused activity on the ground. He concluded, “The results suggest that sunspots and magnetic storms are both manifestations of the same primary cause.” He then suggested that the corpuscle sources were huge electric discharges from inside the Sun into space. These results would have been included in Volume III. Observations of cathodes disintegrating during experiments led Birkeland to conclude that the distribution of matter in interplanetary space was “undoubtedly electric evaporation of the sun’s surface, which must be assumed to accompany the emissions of cathode rays in accordance with our experience of electric discharges from a cathode in high vacuum” (NAPE, p. 624). He observed that “rays from the sun’s polar regions bend down in a simple curve about the equatorial plane of the globe to continue their course outwards from the globe in the vicinity of this plane, strongly resembling the sun’s corona.” The structures seen in his experiments are indeed similar to coronal structures observed during the 1901 eclipse (NAPE, p. 614). In low pressure experiments with no magnetic ﬁeld and low discharge current, the terrella was completely encircled by the cathode glow. This Birkeland described as

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Figure 42. Artiﬁcial sunspots on the terrella sun. Top photograph shows electric discharges from F the terrella with no magnetic ﬁeld. Hotspots reﬂect high-current discharges into relatively lowpressure gases. Spots were easier to make when the terrella surface was roughened with small, sharp prominences. Eruptions became more signiﬁcant with the addition of Leyden-jar capacitors in parallel with the discharge tube. Spots spread all over the terrella surface. Photograph no. 4 shows terrella emissions with a strong magnetic ﬁeld. Spots concentrated in two belts symmetric about the equator. Increasing the ﬁeld moved the zones closer to the equator.

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“a light that resembles the sun’s corona”. He also noted that the corona was not homogeneous. He was very proud of his advanced terrella experiments and wrote: “In addition to purely scientiﬁc reasons, I have also a secondary object, which is to give myself the pleasure of seeing the experiments in the most brilliant form.” His delight in his work consumed him, and he spared little time for other activities. Based primarily on his experiments on sunspots, the solar corona, Saturn’s rings, comet tails, and zodiacal light between 1908 and 1914, Birkeland even developed his own theory about the origin of the solar system. As usual, he subjected his new theory to experimental tests. We should mention, however, that Birkeland’s simulations of cosmic phenomena were not performed with the same rigor as his auroral experiments because he planned to continue them as he wrote Volume III. Based on his discussions of the cosmic simulations, it appears that Birkeland had less patience for systematic laboratory work than in his younger days.

5.3 COMET TAILS Birkeland found comets exciting objects for understanding the forces and processes operating within our solar system. Unlike the Earth, comets are highly unstable. Birkeland’s hypothesis was that corpuscles streaming away from the Sun should interact with all objects in interplanetary space. He performed simulations of interactions between electric corpuscles by producing the ﬁrst artiﬁcial comets in a laboratory. Results suggested several models for the formation of comet tails (NAPE, p. 631). The simplest was an interaction between corpuscles from the Sun with the “vaporous envelope surrounding the more solid part of the nucleus”. It was evident to him that “comets consist of an accumulation of cosmic dust, with various carbonaceous substances, concentrated about one or more nuclei, which are surrounded by a highly rareﬁed vaporous envelope in which possible carbonaceous gases are comparatively strongly represented.” Birkeland assumed that carbon dioxide (CO2 ) was an important constituent of the comet nucleus. Some of the corpuscles “acquire an appendix of gaseous atoms and molecules, which have thereby become luminous”. As the direction of motion of the corpuscles was maintained, a luminous tail formed, directed away from the Sun. Since the solid core has a diameter of only a few kilometers, it is not visible to the naked eye. Comets are visible mainly because of long tails that are formed by solar heating and interactions with corpuscles from the Sun. Comets lose matter at high rates partly because they exert small gravitational forces and lack magnetic ﬁelds to shield them from charged corpuscles.

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Birkeland also considered a model in which cathode rays charged comets to such high potentials that they gave off electrical discharges. He tried to ﬁnd a relationship between the length of the tails and the emission of corpuscles from the Sun, and he attributed variations in the tail length of the comet 1863 III to different pencil beams from the Sun (NAPE, p. 634). He also correlated variations in the tail of comet Encke with the sunspot cycle. It is interesting that Birkeland imagined the possibility that “luminous pencils of rays, emitted by electric discharges from a comet, are bent backward by the electric force of cathode rays from the Sun, in such a manner that the discharges pursue their course almost in the direction of the comet’s shadow, forming approximately a cone, possible on account of the mutual repulsion of the pencil of rays emitted” (NAPE, p. 636). Experiments using the sphere as a cathode created luminous envelopes around the globe that contracted and expanded with changes in the surrounding gas pressure. He noted similarities with structures around cometary nuclei and suggested that discharges could play a role in the formation of luminous structures in comets (NAPE, p. 637). Birkeland was also fascinated by the ﬁne structures and ﬁlamentation he found in comet tails because of their similarity to auroral features. The formation of more than one tail could easily be explained by his theory. He concluded, “The formation of several distinct tails from one comet could possibly have causes corresponding more or less to those of the formation of various distinct pencils of cathode rays in an electric or magnetic ﬁeld.” (Figure 43). In Birkeland’s view, the simulations supported his theory of comet tails. The solar system’s best-known comet is named after the British astronomer Edmund Halley (1656–1742). Birkeland expended great effort to study this comet as it crossed the solar disk on May 18–19, 1910, and he and Krogness made several recordings at Haldde Observatory. He was particularly interested in studying the tail, which he believed consisted of electric corpuscular rays. These should “be drawn into the polar regions owing to the Earth’s magnetism assuming the tail of the comet to be of sufﬁcient length to reach the Earth” (NAPE, p. 638). He speculated that “an alteration of these parts of the comet’s tail near the planet might be noticeable” and urged astronomers to observe the tail of the comet as it passed Venus between May 1 and 3. He assumed that Venus had a magnetic ﬁeld and expected that the comet’s tail would bend toward V the polar regions of the planet (NAPE, p. 640). The geomagnetic ﬁeld appeared to deﬂect the comet’s tail, indicating it contained electric corpuscles. However, no visible aurora could be attributed to the Earth’s passage through the comet’s tail (NAPE, pp. 645–646). In contrast to all contemporary theories of comet tails that emphasize the scattering of light from the Sun, Birkeland’s theory assigned signiﬁcant roles to charged particles. One possibility that he considered had cometary material

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Figure 43. Simulation of comets (NAPE, p. 637). F

“hanging on” to corpuscular rays and becoming luminous through this interaction. A second view was that electric corpuscles from the Sun induced discharges near comets to form the tail. Thus, Birkeland regarded the existence of comet tails as a direct result of solar electrons and ions in interplanetary space. That is, the comet tails were formed by matter ejected from the Sun. “We shall see how our theory of an electric radiation of matter from the sun can give a satisfactory explanation of the comet’s formation, even when its orbit carries it to a distance of 10,000 astronomical units from the sun” (NAPE, p. 639). 5.4 SATURN’S RINGS Saturn is considered a special planet because of the luminous rings found in its equatorial plane. These rings are easily visible with a telescope. Shortly after Birkeland began his terrella experiments, he produced a luminous ring at the equator of the sphere, similar to the rings of Saturn (NAPE, pp. 654–661; Birkeland, 1913b). In 1910, he began systematic simulations of Saturn’s rings and discovered that it was easier to create them by changing the polarity of the discharge. In his 70-liter chamber, he created discharges consisting of as many as ﬁve rings around the terrella. In a 1911 paper to the French Academy, Les Anneaux de Saturne sont-ils dus a´ une radiation electrique ´ de la plan´ete ´ , he discussed the possibility that Saturn’s rings were composed of electrons, ions, neutral atoms and molecules, and cosmic dust. Particles with largest mass relative to their electric charge should be found closer to the planet; those with lower density orbit farther away. These particles soon become electrically neutral, and their orbits become elliptical. Thus, the creation of the Saturnian rings

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Figure 44. Simulation of Saturn’s rings. The experiment was performed in the 320-litre chamber F with a 24-cm terrella which acted as a strongly magnetized cathode. Birkeland’s experiment indicates that: “Corpuscles from the emitting globe form luminous rings in the equator plane” (NAPE, p. 655).

was similar to the formation process for comet tails and the occurrence of zodiacal light. Electric radiation from the planet was accompanied by an ejection of tiny material particles that Birkeland referred to as “electric evaporation”. Combinations of these particles formed the rings. His conclusion was based on the observed disintegration of palladium cathodes during powerful discharges and the consequent blackening of chamber walls near the terrella. His simulations suggested, “Saturn throws off tons of matter every day in the plane of the rings. Thus, the rings are constantly renewed.” He also speculated that Saturn’s moons could have been formed from such ejected matter. In his lecture to the Norwegian Academy on January 21, 1913, Birkeland concluded that existing theories on the rings of Saturn, based on ﬁxed or liquid material, must be wrong. Rather, the important agents were electric corpuscles from the Sun. Birkeland’s hypothesis predicted that the light intensity of the rings should vary with solar activity. With his new photocell technique mounted in front of the large solar telescope at Khedivial Observatory, Egypt, Birkeland studied variations in the luminosity of the rings. Results of these studies were to be presented in Volume III (Figure 44). 5.5 ZODIACAL LIGHT The strange phenomenon called zodiacal light attracted Birkeland’s interest in 1909. Zodiacal light has a long history. Italian astronomer Giovanni Cassini (1625–1712) ﬁrst described it in 1683. He saw a faint, diffuse light stretching up from the horizon along the ecliptic plane, the part of the celestial sphere in which the Zodiac constellations are found. Today, we know that sunlight scattering off dust particles orbiting the Sun near the ecliptic plane causes zodiacal light.

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Under proper conditions, zodiacal light is visible to the unaided human eye, although its intensity is about a thousand times weaker than an intense aurora and even starlight interferes with observations. Diffuse zodiacal light is only seen for 1–2 hours after sunset or before sunrise on moonless nights. It normally appears as an elongated pyramid that reaches 30◦ –40◦ above the horizon and is best observed at low latitudes in deserts where light transmits freely through the atmosphere. Although zodiacal light was a recognized phenomenon long before Birkeland’s study, no scientiﬁc explanation existed, and its cause was a m mystery. To the human eye, the intensity of zodiacal light appears constant. Birkeland, however, was convinced that it must vary, and he mentioned this in a 1911 paper. His hypothesis was that this light might also be caused by ions, atoms, and molecules that accompanied evaporated electrons. Matter ﬂowing out of the Sun both scattered and absorbed sunlight. Zodiacal light was primarily due to scattered sunlight. However, there was still the possibility of a weak contribution caused by emissions from the gas itself. Presumably, the excited emissions would be caused by the impacts of electrons from the Sun. In the laboratory, he produced phenomena similar to zodiacal light using the terrella as a cathode as shown in Figure 45. Birkeland also focused on performing realistic observations. He and Krogness conducted a two-month campaign in Sudan early in 1910. Later, Birkeland and two assistants moved to Egypt. Between 1913 and early 1917, they conducted zodiacal light measurements in Omdurman, Sudan, Helwan, Egypt, and Salisbury, Rhodesia (NAPE, pp. 611– 624). Birkeland believed that geomagnetic storms were caused by intensiﬁcations in the stream of electric corpuscles from the Sun. Since electrons, ions and dust evaporated together, there should be a correlation between the intensity of zodiacal light and disturbances in the Earth’s magnetic ﬁeld. Volume II cites a report by George Jones (1800–1870) who observed simultaneous oscillations in

Figure 45. Laboratory simulation of zodiacal light ((Birkeland, 1914). F

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both. Birkeland, fascinated by this report, asked Karl Devik and a young mathematician, Thoralf Skolem, to help investigate “Jones oscillations” of zodiacal light. The proximity of the Khedivial Astronomical Observatory led Birkeland to establish his base of operations at Helwan, a small town roughly 30 km south of Cairo. The Khedivial Observatory, which had a 30-inch reﬂector telescope, was owned by the Egyptian government but run by the British Survey Department. During Birkeland’s stay, the director was Harold Knox-Shaw, a young graduate of Cambridge University. Before he left Norway, Birkeland received approval from the Secretary of the Royal Society, Arthur Schuster, to use the telescope. Shortly after arriving in Egypt, the three Norwegians continued by train to Omdurman, Sudan, where Birkeland had previously observed zodiacal light. Omdurman, once the capital of Sudan, is near the convergence of the Blue and White Nile rivers. It is also close to the desert where conditions are optimal for observing weak zodiacal light. Weather in Sudan and Egypt affords many cloudless nights in the months of October–November and February–March. Because the intensity of zodiacal light is so very low, observations were carried out in complete darkness. After their ﬁrst night in the desert, Birkeland asked the assistant governor of Omdurman to extinguish city streetlights for the duration of his campaign. Convinced that the impact of corpuscles from the Sun with interplanetary dust contributed to zodiacal light, Birkeland simultaneously recorded magnetic ﬁeld variations at the Khedivial Observatory. Birkeland’s ﬁrst objective was to map the locations, dimensions, and intensities of zodiacal light. The team made sketches and drawings of the light in relation to star patterns and the intensities of starlight. Even weak stars are visible through the haze of zodiacal light. Unfortunately, he could measure only relative but not absolute values of the light intensity. Birkeland was disappointed. Although they had purchased the world’s best camera and many different lenses, they were unable to photograph zodiacal light. They needed exposure times that were much too long for detecting rapid variations. After trying many different types of ﬁlters and ﬁlms, Birkeland concluded that most of the zodiacal light intensity must be at ultraviolet wavelengths ( (Birkeland , 1914). Because the atmosphere absorbs most ultraviolet light from the Sun before it reaches the ground, he planned to make further measurements in mountains about 3,000 m above sea level. However, this campaign was never carried out. Birkeland was also uncertain about the validity of the observations in Sudan and Egypt. Twice he sent Karl to Salisbury, Rhodesia, to acquire simultaneous observations separated by a great distance, hoping to get information about latitude and altitude dependence of zodiacal light intensities. Devik’s ﬁrst trip to Salisbury was in June 1914.

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Together with Karl Devik, Birkeland expended much time and energy trying to develop a new method for recording very weak light signals. He tried using a photocell placed in front of the 30-inch telescope. Elster and Geitel in Germany had developed the ﬁrst photocell just a few months earlier by exploiting the photoelectric effect that had been known for two decades. Thus, Birkeland was a pioneer in testing photocells as a revolutionary way to record weak astronomical signals. Today, photocells and photo diodes are used routinely. At the time, the manufacturing company claimed that photocells were 100 times more sensitive than photographic plates, the predecessor of ﬁlm. Photocells count individual photons after they pass through the ﬁlters and lenses of a detector by measuring the current they generate with an electrometer. The electric signal is proportional to the number of photons hitting the photocell surface. Birkeland hoped to measure the absolute intensity of the zodiacal light and thus identify its variations. He and Devik worked many long days at the observatory with the photocell equipment, but obtained disappointing results. The zodiacal light was still too faint. From earlier experience, Birkeland had learned that the type of lens and reﬂecting material was critical in making good measurements at blue to ultraviolet wavelengths. Krogness and Størmer could take better auroral pictures using a thin cinematographic lens rather than thick Zeiss lenses. Birkeland therefore tested the absorption and reﬂection properties of different metals at different wavelengths. After considering all the materials used in the telescope he concluded “zodiacal light must have wavelengths in the dark blue and down to about 320 nm” ((Birkeland, 1914, 1917). The 30-inch reﬂector had a silver coating that absorbed ultraviolet light. This had to be changed to quartz, ﬂuorspar, or Jena glass that reﬂected ultraviolet light fairly well. He then used the altered telescope to study zodiacal light. In an article on this subject he wrote “If you want to produce a mirror to reﬂect rays of the zodiacal light it is best to choose Mach’s mirror metal that reﬂects ultraviolet light much better than all other known metals or nickel” (Devik archive). Ordinary glass lenses should not be used. With thinner lenses, a mirror made of Mach’s metal and his own photocell, W Birkeland made the ﬁrst measurements of zodiacal-light variations and pulsations. Examples showing marked variations of zodiacal light are included in his 1917 publication. He was also satisﬁed that simultaneous with the zodiacallight ﬂuctuations he observed small, but signiﬁcant variations in the Earth’s magnetic ﬁeld. Since simultaneous recordings of light from isolated stars remained constant, the zodiacal-light variations were not caused by Earth’s atmosphere. Birkeland concluded that the new equipment worked much better, but he still hoped to improve the quality of his measurements. Although Birkeland’s

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contributions to understanding zodiacal light were few, his introduction of photocells to record weak astronomical signals was invaluable. Birkeland had sent Arthur Schuster copies of his ﬁrst two zodiacal-light publications and was gratiﬁed to receive a very positive response on October 15, 1915, from the Secretary of the Royal Society. In the letter, Schuster expressed his hope “that all facilities will be given to Professor Birkeland in order to enable him to carry his experiments to a successful conclusion.” In this instance, the Royal Society actually endorsed Birkeland’s research. 5.6 CONFLICTS WITH CARL STØRMER Carl Størmer (1874–1957), shown in Figure 46, was appointed Professor of Mathematics at the University of Kristiania in 1903 and soon became one of Birkeland’s colleagues. In discussions with Størmer, Birkeland conveyed his belief that auroral research was still limited by traditional ideas and primitive instruments. From his earliest expeditions, Birkeland was open to new ideas, including the possibility that auroral altitude distributions might extend close to the ground. Birkeland showed Størmer his auroral simulations and noted that the trajectories of charged particles reaching Earth from the Sun represented an outstanding geophysical problem. Birkeland had sparked Størmer’s interest, leading him to develop powerful new methods for calculating trajectories of energetic particles in a magnetic dipole. Since no analytic solutions were possible, Størmer developed numerical integration techniques. During the next 15 years, he and his assistants spent more than 18,000 hours making exact trajectory calculations, and Størmer published several papers summarizing this work (Størmer, 1955). His methods are still used to understand cosmic-ray ﬂuxes. Pictures on page 42 compare Størmer’s trajectories of charged particles in the vicinity of the Earth with Birkeland’s corresponding auroral simulation. Taken together, the two ﬁgures demonstrate the complementarity between the auroral simulations and trajectory calculations, indicating that energetic particles form two auroral rings around the magnetic poles. In 1909, Størmer and Krogness built the ﬁrst auroral cameras with sufﬁcient sensitivity to photograph auroras. Earlier Størmer wrote “It is absolutely necessary to gather as many precise observations of the auroral phenomena as possible. . . . The only sure and objective method to obtain the altitude of the auroras is through photography, but for a long time all attempts were in vain.” Based on more than 40 years of work, they determined the altitudes of the northern lights based on triangulation by taking simultaneous photographs of the same auroral forms with cameras 50–100 kilometers apart. These photographs showed that auroral forms ranged in altitude between 90 and 700 kilometers.

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Figure 46. Drawing of Carl Størmer (1874–1957) who calculated the trajectories of energetic F particles from the Sun in a magnetic dipole ﬁeld.

After 1908, as Birkeland extended his terrella experiments to simulate the Sun, comets, and Saturn’s rings, their collaboration ceased (NAPE, p. 553). Birkeland concluded that his laboratory experiments offered a surer path for understanding auroral problems than Størmer’s theoretical calculations (Figure 17, p. 43). Conﬂict between them intensiﬁed after Birkeland published NAPE, his paper Sur l’origine des planets et leur satellites in Comptes Rendus, and gave his lecture to the Norwegian Academy on November 4, 1913. Størmer was very upset to discover that Birkeland used four equations from one of his papers without proper attribution. Størmer insisted that he should be invited to give a similar lecture to the Academy to show Birkeland’s deﬁciency. He even wrote an article for Aftenposten to point out mistakes and called for an ofﬁcial investigation. This was the ﬁrst time two well-known Norwegian professors attacked each other on scientiﬁc matters in public. Birkeland’s reply illustrates the intensity of the conﬂict, reading in part: Størmer claims that my new theory about the creation of the universe is hidden in his equations. It is a pity he did not discover that earlier. In my main book, page 698, you will ﬁnd four expressions that also occur in Størmer’s papers, but they are deduced from the well-known equations of motions. Therefore, I thought a particular reference was not needed. . . . I regret that for years I was so na¨¨ıve as to provide Størmer with help and data.

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If Størmer can get people to believe that his stupid attack on me is correct, it will surprise me. . . . You may claim I have used strong language. True, but I refuse to use the polite language of the Storting on a person who has attacked and tried to strike me from behind (Devik archive).

Disputes between the two continued. The most contentious concerned the importance of positive ions in the auroral processes which is addressed in several papers. The most detailed argument appeared in the 1916 paper “Are the Solar Corpuscle Rays that Penetrate into the Earth’s Atmosphere Negative or Positive Rays?” Here Birkeland wrote, “In cosmic space positive rays from the sun certainly exist. However, they do not seem to penetrate close enough to Earth for their existence to be ascertained in our atmosphere. . . . Positive particles can hardly have magnetic effects.” A critical analysis of this conﬂict, 90 years after it happened, is difﬁcult.

Part III: Technology and Applied Physics

CHAPTER 6

FAST SWITCHES AND ELECTROMAGNETIC CANNONS F

Birkeland’s education and interest in experimental work were the foundations for his entry to the world of industrial invention. He delighted in creating devices that made life easier. Labor saving inventions at Haldde Mountain kept his team warm and well supplied throughout the severe winter of 1899–1900. As a patriot, he felt duty bound to contribute to the growth of Norway’s industrial base. However, he told his friends that his main reason for engaging in applied research was to earn enough money to build a modern laboratory and staff it with bright assistants. Lack of money and equipment was a perennial problem at the University. During Birkeland’s ﬁrst visit to England, he complained to Professor Joseph John Thomson (1856–1940) about his ﬁnancial woes. Thomson advised him, “Do as I. Make an invention to earn you a million, and then you can think of science.” Birkeland apparently followed Thomson’s advice. However, his applied research eventually proved unpopular with some faculty members who resented his ability to attract the brightest physics graduates using outside resources. Birkeland’s ﬁrst practical work with hydroelectric power occurred during his 1899–1900 expedition. A new plant had just opened at the K˚a˚ fjord Copper Mine that generated electricity from a 370-meter high waterfall. The effective conversion of waterfall energy into electricity and the mechanisms used to regulate the ﬂow of high currents fascinated Birkeland. At the time a turning knife acted as a switch, but more reliable devices were needed to avoid serious mishaps in the mine. After returning from the Haldde Mountain expedition, Birkeland worked on electrical switching devices at his University laboratory when he was not otherwise engaged in teaching or writing Exp´e´ dition Norvegienne ´ de 1899– 1900. He began experimenting with induction coils as alternatives to knife switches. In 1901, at the request of the Norwegian Government, Birkeland chaired a committee to study the problems of hydroelectric power stations. He and Thorvald Nordberg-Schultz, director of the new Maridalshammeren Power Station, demonstrated an emergency stop by the knife switch. Fuses were

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destroyed and the electric board broke in half as the power station darkened and began to burn. While others ran to safety, Birkeland felt, “It was the most interesting moment in my life.” The unexpected disaster presented new possibilities. In a few months, Birkeland submitted a patent for a current-braking switch using magnetic induction (No. 11445, dated October 24, 1901 in Appendix 3). In 1902, he formed Strømbryterkompaniet (Current-Switching Company) to manufacture this new type of switch. A French ﬁrm offered to ﬁnance Birkeland in exchange for 50% of the royalties, but Strømbryterkompaniet closed after two years when funding failed to materialize. In its early stages, the United States anti-ballistic missile program considered developing “rail guns” that would shoot projectiles capable of hitting and destroying re-entry vehicles. Some rail guns can accelerate projectiles to velocities near 20 km/s. It is not widely appreciated, however, that the rail gun is the direct descendant of an “electromagnetic cannon” patented and built shortly after the turn of the 20th century at the University of Kristiania by Kristian Birkeland. During the summer of 1901, while working on magnetic induction switches that quickly connect and disconnect electrical currents, Birkeland noticed that pieces of iron were attracted into solenoids with such force that they ﬂew through the coil like bullets. He began experimenting with a series of straight induction coils. Although this phenomenon had been seen previously in other laboratories, it was Birkeland who saw its potential for accelerating projectiles. In an interview two years later, Birkeland recalled that after 10 days of working around the clock, he ﬁnished the construction of his ﬁrst cannon and submitted a patent application. His ﬁrst patent is dated September 16, 1901 (Patent no. 11201, Appendix 3) (Figure 47). Birkeland’s idea was to use the projectile itself to switch current on in the solenoid ahead of it and turn current off in the solenoid behind it. This imaginative design used the projectile as a moving switch that opened circuits behind

Figure 47. Birkeland’s original drawing of his ﬁrst electromagnetic cannon. F

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Figure 48. A part of Birkeland’s original letter which also illustrates his handwriting at the age F of 34.

it, both saving electrical energy and sustaining a forward-driving impulse, until it exited the cannon at top speed. Birkeland ﬁrst used a Faraday disc generator as the power source that could deliver 2,000 Volts and 50,000 Amperes for a fraction of a second. The cannon’s design was both elegant and straightforward. Birkeland facetiously compared his gun with Baron Munchhausen’s r 1, w rope which was cut below and spliced to the top as he climbed up to heaven. The challenging problem of switching currents off forced several redesigns, eventually requiring ﬁve different patent submissions, the last in April 1903. The largest cannon was nearly 3 m long, had ten groups of solenoids, with 300 coils in each group. Shortly after receiving his ﬁrst patent, Birkeland invited four inﬂuential people, including two high-ranking military ofﬁcers and one person each from industry and the government, to form a ﬁrearms company. Part of his original letter of invitation, sent on September 17, 1901 to Gunnar Knudsen, appears in Figure 48. An English translation reads: Dear Engineer Knudsen, I have recently invented a device that uses electricity instead of gunpowder as a propellant. With this device it is possible to shoot large amounts of nitro-glycerine over great distances. . . . I have already applied for a world patent. Colonel Krag has witnessed my experiments. . . .

1

Karl F. H. Munchhausen lived in Germany nearly 250 years ago. He became so famous for his stories, published in The Adventures of Baron Munchhausen (1785) that he was awarded the title of baron. Translations of his book into many languages reﬂect its wide popularity.

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A company, consisting of a few men, will be formed to furnish the capital needed to build several cannons. I invite you, who have generously supported my basic research, to participate in this company. The idea is, if the cannon works, as I believe it will, that Colonel Krag and I should present it to Krupp and others in the weapons industry, to sell the patent. Naturally, it will be like playing the lottery. y . . . However, your contribution will be relatively small, and I believe your chance for a proﬁt is good. I prefer to receive your reply by telegraph. Naturally, this must be kept secret for a while. With kind regards W Kr. Birkeland

As usual, he was in a hurry, and Knudsen was asked to respond by telegram. Knudsen replied, “With pleasure I accept your invitation. . . . I promise to keep smiling even if the big lottery does not pay off.” They formed a joint-stock company called Birkeland’s Firearms in November 1901 with 35,000 Norwegian kroner divided into 35 shares. Birkeland received ﬁve free shares as payment for his initial work. The ﬁrst electromagnetic cannon was completed late in 1901 at a cost of 4,000 kroner. Its half a kilogram projectile accelerated to 80 m/s. A model cannon one-meter in length was demonstrated in Berlin on May 15, 1902, where it drew much attention. The largest cannon was 65-mm calibre, nearly 3-meters long, and cost 10,000 kroner to produce. In his characteristically efﬁcient way Birkeland led the ﬁrearms project, continued teaching his physics classes, and planned the 1902–1903 auroral expedition. In 1902, Birkeland and Knudsen demonstrated an electromagnetic cannon to King Oscar II of Sweden, who was mainly interested in its maximum range. The King’s face lit up when Knudsen told him the cannon could hit Russia from Oslo, a range ten times longer than Birkeland’s estimate. However, at the time of his third patent application, Birkeland wrote, “To launch an iron projectile of 2000 kg, containing 500 kg nitro-glycerine with an initial velocity of 300 m/s, would require a 27-meter long tube. The accelerating force would be 180 kg/cm2 .” Clearly, by then, Birkeland was thinking more about a serious weapon of war than just an interesting physical phenomenon. Birkeland demonstrated the cannon at the Academy of Science and Letters on Saturday, March 6, 1902, ﬁring three rounds against a 40-cm thick wooden wall. This demonstration was reported in several newspapers as well as in English Mechanics and World of Science as a great success. Here Birkeland ﬁrst mentioned a new method to minimize sparking within the cannon. He then designed circuits so that as a projectile passed a coil it induced a current equal and opposite to the original one. Thus, switching currents off worked without generating sparks.

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Figure 49. Photograph of Birkeland’s largest cannon, now located at the Norwegian Technical F Museum in Oslo.

Impressed by his success, a German ﬁrm offered to purchase the company, but when Birkeland laid the proposal before the Company’s Board of Directors, they were not satisﬁed with the price. Since Birkeland needed money to support his basic research, the Board agreed to arrange a public lecture at the University on March 6, 1903, at 5:30 PM. This evening proved to be a critical turning point in Birkeland’s career. Even though the highlight of the lecture was a demonstration of his largest cannon, the University allowed him to use the Old Banquet Hall. The event was ofﬁcially announced in the newspapers, and there was not an empty seat in the hall when the demonstration began. Several hours before the lecture, Birkeland and his assistant had test ﬁred the cannon and hit the oak target without any technical problems. However, during the lecture itself, a short circuit occurred. Birkeland’s summary of his “lecture” comes from his assistants, Devik and Sæland. An English translation reads: The cannon was placed in the University’s old banquet hall and pointed towards a target, consisting of a ﬁve inch thick plank of solid wood. The dynamo that supplied power was placed just outside the hall. I closed off space on both sides of the projectile’s trajectory. Fridtjof Nansen refused to follow my advice and placed himself inside the closed-off space. Except for this area, the hall was ﬁlled with expectant people. In the ﬁrst row of seats were representatives from Armstrong and Krupp, the largest weapons forgers in Europe. I went through the physical principles on which the cannon was based, then said ‘Ladies and Gentlemen, you may calmly be seated. When I pull the switch, you will neither see nor hear anything except the projectile hitting the target.’ With this I pulled the switch. There was a large ﬂash of light, and a deafening hissing noise. The bright arc of light was due to a 10,000-Ampere short circuit. Flames shot out of the cannon’s mouth. Some of the ladies in the audience shrieked. Panic followed in a moment. It was the most dramatic moment of my life. With this shot, my stock fell from 300 to 0 in value. However, the projectile did hit the bull’s eye.

Both the date and description of the event differ from a report found on the webpage of Hydro Media, Porsgrunn, which claims that the projectile became

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stuck in the cannon’s barrel about a half meter from the aperture. This contradicts the recollections of both Olaf Devik and Sem Sæland that the projectile struck the target during the exhibition. Since Hydro Media’s description cannot be documented by any contemporary source, the webpage will be revised. The projectile is now welded to its opening so that visitors to the Notodden museum can see the cannon as it looked just before the unfortunate misﬁre (Figure 49). Whether the projectile hit the target or not, the demonstration was a failure. The large ﬂash and noise so frightened the businessmen that Birkeland could sell neither his patent nor the cannon. The electromagnetic cannon received a little further attention, but he had stumbled onto a new project that would consume much of his time and energy (Figures 50 and 51). Birkeland had a distinctive ability to exploit unexpected opportunities, even under difﬁcult circumstances. Although the canon seemed a dismal failure, he realized that the brilliant ﬂash of light opened a new ﬁeld of research. The short circuit had destroyed his power supply, but the coils did not burn. Such “artiﬁcial lightning” could produce nitrogen fertilizer, a much needed commodity. Thus, a seemingly disastrous spark led to one of Norway’s greatest industrial miracles. While some have suggested that Birkeland was not the ﬁrst to construct an electromagnetic cannon, this is difﬁcult to prove. Other curious instruments cannot be compared with Birkeland’s invention. His design was unique, and he clearly held the ﬁrst patent in the world. In April 1903, Birkeland was asked to submit an offer for the cannon to the French Secretary of War. His letter addressed to Monsieur le President de la Commission des Inventions received no ofﬁcial reply as far as we know. On July 11, 1903, Birkeland extended an offer to Lady Sander, who had been in Kristiania for the demonstration. Birkeland expressed his willingness to spend several years in England to help develop the cannon if she could guarantee ﬁnancial support (Figure 52). According to Jago (2001, p. 224), about six months prior to the outbreak of World War I, Birkeland wrote letters from Egypt to Lord Rayleigh and Dr. R. T. Glazebrook, members of the British Commission for the Examination of Inventions of War. Both letters offer the British government free access to develop and use his electromagnetic cannon. At the time, the daughter of King Edward VII of England was Queen of Norway. He attached three conditions ( (Jago , 2001, p. 224): 1. Absolute discretion: Birkeland’s name would appear in no documents. 2. When a weapon was completed, it would be made freely available to Norway. 3. Armaments based on this technology must never be used against Scandinavian people.

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Figure 50. Drawing of Birkeland’s gala lecture in the Festival Hall where he demonstrated his F electromagnetic cannon. On this occasion newspapers were less gracious, but Birkeland maintained his good humour.

Figure 51. Contemporary cartoon from the Kristiania newspaper Viking F V of Birkeland and his cannon. The caption “Birkeland shot the parrot”, suggests that his cannon’s hitting the target was regarded as lucky.

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Figure 52. Copies of letters to Monsieur le President de la Commission des Inventions and to F Lady Sander, the rich and powerful British factory owner.

Birkeland’s request for complete discretion reﬂected a growing anxiety that his invention of the electromagnetic cannon might expose him to physical danger. A meeting with Francis Dalrymple of the British Inventions Board in late November 1916 in Cairo seems to have led to no substantive agreement (Jago ( , 2001, p. 253).

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Near the turn of the 20th century, Sir William Crookes, then President of the British Association, drew attention to “the near exhaustion of the world’s stock of ﬁxed nitrogen”. The most widely used agricultural fertilizer in Europe was sodium and potassium nitrate, bird droppings built up and hardened through millennia. Called Chile saltpeter, these nitrate fertilizers were being mined to exhaustion. In the consequently bleak Malthusian scenario, it would soon be impossible to feed the world’s population which was growing rapidly. Crookes estimated that the global supply of saltpeter might only last about 30 more years. Total exhaustion of fertilizer, with the specter of mass starvation, would follow in four years. It was well known that nitrogen oxides are produced in lightening discharges and that small amounts of nitric acid could be produced in laboratories. Two American engineers, Bradley and Lovejoy, explored the possibility of oxidizing atmospheric nitrogen using power generated by Niagara Falls (Electrochem. ( Ind., 1, 1903). They formed a company called Atmospheric Products and built a ffactory near the falls. In 1903, they were the ﬁrst to attempt to synthesize nitric acid from air on an industrial basis. They generated electric ﬂames using continuous current at 10,000 Volts. To interact with the largest possible volume of air, they divided their large arc into many small arcs, creating as many as 414,000 arcs per minute. A rotating frame with projecting electrodes generated the discharges that were immediately interrupted with platinum rods. Unfortunately, their complicated technique was too unstable, and their enterprise was doomed to failure. When production rates failed to reach proﬁtable levels, the enterprise went bankrupt in the summer of 1904.

7.1 PLASMA TORCH AND NITROGEN FIXATION From the time of its founding in 1905, Norsk Hydro has been a major industrial enterprise, ranking among Norway’s largest companies. Initial success was based on Birkeland’s invention of the plasma arc and the consequent development of the Birkeland–Eyde industrial method for nitrogen ﬁxation. The term “nitrogen ﬁxation” describes natural or artiﬁcial processes by which the

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normally inert atmospheric gas nitrogen forms chemical compounds. Since Norsk Hydro has been the subject of several books and doctoral dissertations, our summary is relatively brief. We focus on Birkeland’s contributions and his relations with the Director General Sam Eyde and the Swedish banker Marcus Wallenberg who was Chairman of the Norsk Hydro Board for more than 40 W years. On February 13, 1903, Gunnar Knudsen, then Secretary of Agriculture, invited Birkeland to a formal dinner party (Figure 53). Among the guests was Sam Eyde, the head of a large Scandinavian engineering company. Birkeland and Eyde had never met, although they knew of each other by reputation. Eyde was a year and a half older, but they had ﬁnished high school in the same year. Eyde came from a family of wealthy ship owners in southern Norway and was educated as a construction engineer in Germany. He was very proud of his degree and openly regarded German technology as the best in the world. In the eyes of some business colleagues, Eyde was actually insecure about his education, but would never admit it. Eyde married a wealthy Swedish countess, the daughter of his parent’s friends. Thus, Birkeland and Eyde came from very different backgrounds. Physically, Eyde was slightly taller than Birkeland, but more powerfully built. He always dressed well, with gold rings adorning his ﬁngers. Eyde never deviated from his goals and always exuded a sense of unshakeable conﬁdence. In 1939, Eyde published his lengthy autobiography My Life and Accomplishments ((Mitt liv og mit livsverkk). According to his autobiography, Eyde had just purchased two of the biggest waterfalls in Norway. After reading Bradley and Lovejoy’s paper, he was very interested in the industrial production of fertilizer and needed the largest supply of artiﬁcial lightning in the world. Birkeland responded, “I can certainly make a large amount of artiﬁcial lightning.” He described his experience with short-circuit discharges that had enabled him to produce intense electrical arcs while testing his electromagnetic cannon. Birkeland already had a small electric w furnace at the University, purchased during an 1897 visit to Paris. He used it for laboratory analyses of geological material in cooperation with well-known geologist Professor Waldemar C. Brøgger. As dinner concluded, Birkeland and Eyde agreed to meet the next day to examine the cannon and discuss possible collaboration. Once they decided to work together, Eyde drafted legal documents in which they agreed to apply for joint patents. Their ﬁrst company, called Birkeland’s Partnership, began operating in the spring of 1903 with a total capital of 15,000 kroner. All work was conducted in secret. Eyde’s role was to obtain the funds needed for test and development as well as administrative overhead. Since Norway was still a poor country, it was not easy to sell capital investors on the idea of a large Norwegian fertilizer industry. He was, however, extraordinarily well connected and a persuasive

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Figure 53. Drawing of the formal dinner party at Gunnar Knudsen’s home in Kristiania on F February 13, 1903. The lady to the right of Birkeland is Knudsen’s daughter.

salesman. Initially, the heaviest burden fell on Birkeland who worked day and night teaching his physics classes while working on the electromagnetic gun and electrical switches. The weekend after their meeting Birkeland stayed at the University writing a new patent application. On February 20, 1903, a week after their ﬁrst meeting, Birkeland submitted the ﬁrst patent application for a fertilizer furnace called: A new approach for producing electric discharges with maximum surfaces for decomposing or binding of gasses in the atmosphere ( remgangsmaade til at fremstille elektriske lysbuer av størst mulig overﬂade til (Fr bruk for binding av atmosfærens gasser). Over the next three years, Birkeland took out several other patents related to nitrogen ﬁxation (cf. Appendix 3). While both partners worked hard to solve the technical and ﬁnancial problems, the collaboration between Birkeland and Eyde appears to have been on shaky ground from the beginning (Figure 54). In the fall of 1904, Eyde sensed that their industrial process for nitrogen ﬁxation would be successful, but discovered that the related patents were in Birkeland’s name alone. He was furious, insisting, “my contribution is just as important as yours.” Henceforth, he demanded that two names must be used when referring to related processes and devices, namely, the Birkeland–Eyde w method and the Birkeland–Eyde furnace. Birkeland, still unsure of success,

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Figure 54. Birkeland’s ﬁrst experimental nitrogen-ﬁxation setup at the University. The furnace F is mounted at the top between the large electromagnets. Nitric acid was collected in a glass container.

acquiesced. Eventually, Birkeland took out 32 patents related to fertilizer production, with Eyde as a co-inventor on three. Arguments about ownership were eventually resolved in 1910 when Norsk Hydro ofﬁcially purchased all of the patents. We note, however, that despite their disagreements, Eyde and Birkeland worked reasonably well together until then. They even started a new project on radiowave propagation in 1907. By the end of June 1903, the enterprise moved out of the University because the available 3,000 Volts was too low. All equipment, including a small furnace, pumps, large electromagnets, and generators, was moved to a warehouse near the fjord in the Frogner section of Kristiania. At the time, the warehouse was little more than a wooden shed. In May 1903, Jørgen Rødseth, who was working on a master’s degree in chemistry, became Birkeland’s ﬁrst assistant. Eivind

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Næss, a construction engineer, joined the team to assist while Birkeland was away at international conferences. Birkeland’s friend Claus N. Riiber (1867– 1936), who later became a Professor of Chemistry at the Technical University in Trondheim, arrived in August 1903. Their growing need for electrical power forced them to leave the Frogner warehouse and move to Ankerløkken, also in Kristiania. The team expanded to include construction engineers to resolve furnace-related problems and chemists to work on the absorption system. Some of Birkeland’s friends later came to view these new assistants as Eyde’s spies. Birkeland himself had no problems working with them. For his part, Eyde continued to push for quick results while Birkeland struggled with the furnace’s performance. On October 15, 1904, the tests moved to Arendal, nearly 300 km southwest of Kristiania, close to a new power station, where they had access to 370,000 Volts. Here, they tested the furnace that would later be used in the ﬁrst f factory. Birkeland faced unrelenting pressure to get the furnace and the absorption system working. Their ﬁrst attempt to produce saltpeter within the fertilizer furnace had to succeed; there was no money available for a second chance. Furthermore, competition lurked in the background from the German industrial giant Badische Annilin und Soda Fabrik (BASF) whose chief engineer Otto Schonherr ¨ had been working on a chemical method to produce saltpeter since 1897. Birkeland decided to use more efﬁcient, alternating current plasma furnaces driven by big generators rather than a pulsed-current torch to produce nitrogen oxide. The main unit used a 50-Hertz alternating current furnace and an electromagnet to generate intense, circular electric arcs between the two electrodes. Arcs formed, broke, and reformed 50 times per second. The arc ﬂipped rapidly as the polarity of the current changed, making the arc look like a continuous glowing disc. Temperatures exceeded 3,000◦ C. Potassium nitrate was the ﬁrst product of the plasma torch (Figure 55). During tests, the torch was fully enclosed in ﬁrebricks. Large pumps forced air to ﬂow through the electric arc. In the high temperatures of the arc, air molecules moved faster and collided more frequently. In the accelerated interactions, nitrogen combined with oxygen to produce nitrogen oxide (NO2 ) gas that was then pumped through water to create nitric acid (HNO3 ). The acid then trickled over limestone (CaCO3 ) to produce calcium nitrate (CaNO3 ), popularly called Norwegian saltpeter. The brilliance of Birkeland’s discovery was to draw nitrogen oxide out of the air by using large electromagnets to focus the electrical discharge disc. To this day, it is called Birkeland’s plasma torch. The process demanded huge amounts of electrical power, but Norway is blessed with many waterfalls. At the time, every aspect of the endeavor was new. Components needed to overcome problems during construction of the furnace and absorption system had to be designed, built, and tested for the ﬁrst time. Birkeland’s

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Figure 55. Intense circular electric arcs were produced between two electrodes more than 1 m F in diameter.

team of chemists, mechanical and electrical engineers often worked for 36 hours without sleep. However, the team was young and enthusiastic, and each test took them a step closer to a ﬁnished design. They wisely maintained a close collaboration with the University of Agriculture to test products on different types of plants and thus establish the best concentrations. Each new test in the fertilizer furnace produced steadily improving results, conﬁrming its potential for industrial application and allowing Eyde to raise more capital from Swedish bankers. The most important was Marcus Wallenberg (1864–1943), director of Enskilda Banken and a member of one of the world’s richest families. The banker Knut Tillberg and the Swedish consul Niels Persson also made large investments. A new company Norwegian Nitrogen Company ((Det Norske Kvelstoff-Kompaniet), called Kvelstoffkompaniet for short, was created in December 1903 with a capital of 500,000 kroner. Birkeland owned one-ﬁfth of the shares. In January 1904, they formed The Norwegian Company for Electrical Industry ((Det Norske Aktieselskap for Elektronisk Industi) that was responsible for building their ﬁrst factory at Notodden. In April 1905, another company called Electrochemical Industry (ELKEM) M formed with a capital of 5 million kroner. The Wallenberg family owned most of its shares. Later the French bank Paribas would invest large sums in ELKEM. During the spring and summer of 1903, Birkeland worked so hard on the industrial fertilizer project with the hydroelectric industry that his involvement

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with the other two small ﬁrms completely stopped. He had no time to think about his auroral campaign. As is evident from his publication list, he completed no basic research papers between 1903 and 1906. Ultimate success justiﬁed this sacriﬁce. Birkeland was responsible for building the ﬁrst nitrogen-ﬁxation factory in Telemark province, on the eastern shore of Heddal Lake in the town of Notodden, nearly 120 kilometers west of Kristiania. At the time, Notodden was a small farming village of a few hundred people. Telemark province is the natural and cultural center of Norway. It has several large waterfalls, and the Svælgfors Power Station had recently been built near the factory site. There was no better place in the country to establish a new industry requiring large amounts of electrical power. At the time, traveling to the factory from Kristiania was difﬁcult, involving a four-hour train trip to Kongsberg followed by a three-hour drive across high hills via horse drawn carriage to Notodden. An alternative was to travel by train to Porsgrunn and take a boat through a series of narrow canals to Notodden. This route took more time, but passed through extremely beautiful scenery. In 1905, work commenced on a railway to connect Porsgrunn and Notoddem. Birkeland found this new work phase difﬁcult and frustrating as tensions with Eyde grew. At the same time, the crisis with Sweden was intensifying, which created deep concerns. Except for Riiber, all of the absorption-system experts were from Sweden, and they were growing nervous. 7.2 FOUNDATION OF NORSK HYDRO After nearly three years of tests and experiments, a committee of international experts convened on July 20, 1905, at Notodden to evaluate the ffactory. The committee included four ﬁnancial experts, Marcus Wallenberg and three foreign-loan directors from Paribas. A British scientist, Professor Silvanus Thompson, chaired the committee. The other committee scientists were Professor Otto Witt from Germany and Dr. Alphones Th´e´ ophile Schlosing from France. Sam Eyde acted as the committee administrator and Birkeland as its technical director. Earlier Birkeland and Thompson had collaborated on a scientiﬁc paper. Birkeland ﬁrst explained the workings of their 500 kW furnace. He then showed them the large electric discharge disk and demonstrated the granite tower where the NO gas was absorbed into water. It took some time before the committee reached a conclusion. However, both Birkeland and Eyde felt that even though the present production rate per kilowatt power was relatively low, the members had been positively impressed. In their deliberations, the committee members concluded that the factory produced sufﬁcient quantities

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Figure 56. Sketch illustrating the different steps in the nitrogen-ﬁxation process from the power F station to the left to the ﬁnal fertilizer product to the right. The big towers in the middle are the absorption system.

of saltpeter to turn a proﬁt. Birkeland was still unsatisﬁed with the production rate of 450 kilograms per kilowatt-year (kg/kW-yr), and wrote several letters proposing bigger furnaces. His minimum goal was 600 kg/kW-yr. To persuade international bankers, Eyde even mentioned a rate of 900 kg/kW-yr. To be proﬁtable, the factory had to produce enough fertilizer to more than cover electricity costs (Figure 56). After hundreds of experiments conducted in secret under Birkeland’s guidance, a new company, Norsk Hydro, was formed with Sam Eyde as the ﬁrst managing director and Birkeland as the technical director. The formal name is Norsk Hydro Electric Nitrogen Company (Norsk ( Hydro Elektriske Kvelstoff Aktieselskap). On December 5, 1905, its Notodden Fertilizer Factory ofﬁcially opened (Figure 57). Norsk Hydro was Norway’s ﬁrst multinational company with a value of 7.5 million kroner. Marcus Wallenberg chaired the board of directors. The other initial board members were Knut Wallenberg (1853–1938), Marcus’ brother and director of Paribas, Admiral Børresen (1857–1943) of Norway, together with Knut Tillberg (1867–1946) and Niels Persson from Sweden. Birkeland especially enjoyed the company of his team of young engineers and deeply appreciated their dedication. Both Birkeland and Eyde gave special lectures to celebrate the opening of Norsk Hydro. Birkeland spoke at the University Festival Hall; Eyde talked to a more general audience of engineers and administrators at the Polytechnic

Figure 57. Photograph of the new factory in Notodden. F

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Figure 58. Cartoon showing Birkeland making fertilizer by wringing dung from the skies. “It F smells terrible!”

Society. Published manuscripts of their addresses strongly suggest that Birkeland wrote both speeches. The fact that Norway, through the Birkeland–Eyde method, played a leading role in averting a global famine was highly popular and diverted attention from the continuing crisis with Sweden. Making fertilizer out of the air drew enormous attention, and contemporary cartoons show Birkeland wringing dung from the skies (Figure 58). Journalists from all over the world sought interviews, and Birkeland was pleased with Eyde’s many foreign press contacts, while in Norway Birkeland’s contributions received the most attention. Other assessments in Norwegian newspapers pointed out that Eyde and Birkeland owned only 8% of the Norsk Hydro shares while bankers organized and/or controlled by the Wallenberg brothers owned the rest. Nationalist sentiments aside, international ﬁnancing of Norsk Hydro foreshadowed the dominant economic model of the late 20th century. On August 15, 1906, Birkeland resigned as a director at Norsk Hydro. He found the work insufﬁciently challenging and dearly wanted to return to basic research. As Norsk Hydro evolved toward an international entity, he was increasingly disappointed that Norwegians were not in control. Never again would he become involved in big business. The board wanted to keep him as a technical consultant and offered him 10,000 kroner per year for as long as he lived. A guaranteed salary for life was new to Norway. In return, Birkeland agreed to return whenever needed for consultation. He also promised never to

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work for or form a competing company. In addition, Norsk Hydro could also call upon him to give international lectures. For every new factory that opened in Norway, he would receive an additional 5,000 kroner. If fertilizer factories using the Birkeland–Eyde method opened in other countries, he would receive 50,000 kroner. Thanks to the establishment of Norsk Hydro, Birkeland became even better known and respected at the University and throughout the country. The University Administration found it increasingly difﬁcult to reject any of his proposals. We note, however, that Birkeland had signiﬁcant problems getting Norsk Hydro to pay the agreed consultancy fee and to adjust it for inﬂation. His lawyer Johan Bredal did an excellent job, and in 1915 Birkeland received 20,000 kroner per year retroactive to 1914. In 1917, his stipend increased to 24,000 kroner per year. Early in 1910, Norsk Hydro asked Birkeland to chair a committee to determine the most cost-effective way to produce fertilizer, the Norwegian or the German BASF method developed by Otto Sch¨o¨ nherr. The Germans had invested signiﬁcantly in Norsk Hydro and were unhappy with the agreement regarding production at 1905 levels. Shareholders were interested in earning more money on their investments, and BASF ofﬁcially complained that the Birkeland–Eyde furnace was less efﬁcient than the new German design. All shareholders agreed that the more efﬁcient method should be used. They decided to conduct a competition at Notodden, evaluated by the committee of experts chaired by Birkeland. For the good reputation of Norway, Birkeland felt it critical that the Norwegian design be chosen. However, rumors circulated that Eyde had come to favor the German design. Birkeland had to spend several months away from the University and found a qualiﬁed substitute to take over his lectures. He then set out to judge the competition in Notodden, which had grown into a bustling town of more than 5,000 people. On the way, he also visited Rjukan, where work had started on the world’s largest hydroelectric power station and a new fertilizer factory. More than a 100 million kroner were invested in its construction. On arriving at the factory in Notodden, he immediately realized that his furnaces needed serious upgrades. The engineers had tried in vain to increase production using traditional methods. Birkeland decided that a much larger, more powerful furnace must be built, but only about six weeks remained before the ﬁnal test. Against this time constraint Birkeland and his team of young engineers constructed a new 2,000-kW furnace. Given the number of people and time available, the accomplishment was amazing. Birkeland’s enthusiasm carried the day. On the ﬁnal day of the competition, the Norwegian and German furnaces ran continuously for 24 hours. Neither could be left unattended for a moment, and only engineers were allowed to make adjustments. Both teams worked

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continuously for 36 hours. The quantities of fertilizer output were carefully weighed to determine which was the more efﬁcient furnace. The technical results were regarded as a draw, even though the Norwegian furnace produced more saltpeter. The Germans complained that the Norwegians did not use their original furnace and wanted the new furnace disqualiﬁed. However, no regulation had forbidden changes. Birkeland protested the conclusion as unethical. Then and later Birkeland insisted that his construction had proved superior. Since Eyde had expected the Norwegian furnace to lose the competition, he was quite willing to accept a draw. Because the decision was difﬁcult to explain to the workers, in new factories both the German and Birkeland–Eyde furnaces would be used. Birkeland was bitterly disappointed by the competition’s conclusion and wrote a long letter to the board of Norsk Hydro in which he complained, It is evident that when the public comes to understand this cowardly conclusion, it will be clear to all that the people from BASF, and possibly Norsk Hydro, are without honor. Through its brutality BASF has won.

Birkeland sold most of his shares in the companies in 1906 and 1907 for 135,000 kroner, well below market value. In 1910, he sold his remaining shares. In addition to his yearly stipend from the company he received more than 200,000 kroner, 40 times his salary at the University. Birkeland regarded himself as well compensated for his four years work on nitrogen ﬁxation. While he received much less than Eyde, Birkeland gained and enjoyed ﬁnancial freedom. To a large extent Birkeland’s Plasma Torch was an unexpected result of the T short circuit during the fateful demonstration of his electromagnetic cannon. In that brief instant the plasma torch was born. Since he was the ﬁrst to demonstrate it, it became known as Birkeland’s Plasma Torch, and its discovery led to the development of plasma furnaces to produce nitrogen fertilizer. This was the ﬁrst application of a plasma torch. Between 1905 and 1940, Norsk Hydro generated almost 5 million tons of fertilizer from air, enough to produce 25 million tons of grain ((N. Henriksen, 1995). By 1940, Birkeland’s furnaces were no longer needed for fertilizer production, and the Birkeland–Eyde method was replaced with the more efﬁcient Haber–Bosch process (Storækre, 1980). Fritz Haber (1868–1934) was the German physical chemist who won the Nobel Prize in Chemistry 1918 for developing a practical method to combine hydrogen and nitrogen at high temperature and pressure to form ammonia gas, N2 + 3H2 ←→ 2NH3 + H. The reaction is both reversible and exothermic. To maintain a positive accumulation of ammonia as the temperature increases, NH3 gas must constantly be removed from the reaction tank. Karl Bosch (1874–1940) and Friedrich Bergius (1884–1949) shared the Nobel Prize in Chemistry in 1931 for their high-pressure chemical studies. Bosch adapted

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Haber’s experimental techniques to industrial scales. Because the Haber–Bosch process does not require large amounts of electrical power, it has immediate advantages in countries with less hydroelectric power than is available in Norway. Historically, Haber–Bosch has been a two-edged sword. It provided the technical basis for fertilizer needed to sustain the “green revolution” that feeds today’s global population. It also sustained the German munitions industry through two world wars. Plasma torches have present-day applications (Per ( ratt, 1996). Today we distinguish between pencil-point electrode heaters or furnaces and the coaxial gun-barrel plasma arc discharges. We call the latter a torch. The short circuit in Birkeland’s cannon was the ﬁrst demonstration of a non-transferred torch. Non-transferred plasma torches employ a rear electrode and a front electrode. In plasma physics, this is the more interesting torch conﬁguration. The currentcarrying plasma displays several fundamental magnetohydrodynamic modes, including ﬁlamentation and shooting electric corpuscles away from the electrodes, i.e. out of the mouth of a plasma gun or cannon. The intense short-cut ﬂame gave Birkeland the idea of using electrical energy, through AC furnaces, in fertilizer production. The motions of charged particles produce electromagnetic radiation ((Perratt, 1996). Modern plasma torches have multiple applications in the production of acetylene and in the steel industry. They are also used to process integrated circuits, and parts, and to harden tools. After a gestation period of almost a century, the plasma torch today offers a global solution to glassify and store radioactive waste. 7.3 CONFLICT WITH SAM EYDE While a student, Sam Eyde was proud of his talents as a dramatic actor. As a salesman he attached great importance to his appearance and making a good impression. Soon after the Notodden factory opened, Eyde built a grand administration house with a central room capable of holding more than 100 guests. Views from the house of the surrounding countryside are spectacular. Eyde worked hard to impress inﬂuential politicians, newspaper owners, and aristocrats who could be of help to him (Figure 59). Newspapers treated him as a hero. He enjoyed large parties and expensive cars which even the Norwegian king borrowed for the beneﬁt of foreign visitors. Eyde’s marriage to a Swedish countess, whom he divorced in 1920, probably contributed to his grand lifestyle. He excelled at starting new projects, including several other companies, and he sought recognition as a Grand Seigneur (Figure 60). Hospitality to industrial and military leaders was a paramount concern. Indeed, the German Kaiser, the King of Thailand, and a Japanese prince visited him at Notodden. Although lacking military experience, he was commissioned a major in the army.

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Figure 59. When important guests visited Notodden, Birkeland was asked to guide them through F the factory. This picture shows Birkeland with King H˚a˚ kon VII in 1908. Birkeland is third from the left, the King is in the center, with Eyde standing to his left.

He was a member of the Storting from 1918 to 1920 and the Norwegian ambassador to Poland from 1920 to 1923. He did well in neither position. After 1923, Eyde mostly lived outside Norway. Because he recommended that foreigners buy Norwegian waterfalls, he became unpopular in the Storting where foreign control of Norwegian industries was resented. However, Norwegians in general admired and respected him for the thousands of jobs he created. Serious conﬂict between Birkeland and Eyde began after 1910. Birkeland did not receive promised bonuses for the start of new factories and his consultant fees were not adjusted for inﬂation. He complained to the Board Chairman Wallenberg that Eyde had not lived up to their written agreements. The conW ﬂict intensiﬁed when Birkeland learned that in 1912 patents had been sold to Spain and Portugal under the name “Eyde–Birkeland method”. In a 1913 letter, Birkeland blamed Eyde for “outrageous baseness toward me and my

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Figure 60. Portrait of Director General Sam Eyde (1866–1940) showing him as the Grand F Seigneur.

co-workers that has lasted for years”. However, the basic conﬂict between them grew out of Eyde’s attempts to convince people that he was a researcher who had actively participated in technical and chemical experiments that Birkeland conducted. In Egypt, Birkeland learned that Eyde was rewriting the history of the fertilizer industry, and the Birkeland–Eyde method had become Eyde–Birkeland. In the spring of 1915, a book called Oppﬁndernes liv (Lives of Inventors) was published by Nordisk Forlag in Copenhagen, with Helge Holst as editor. It contains a long chapter about the Birkeland–Eyde furnace. Almost by accident

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Birkeland received a copy of the book. A Norwegian, Per Wendelboe, nominally wrote the chapter in collaboration with Eyde. In a letter, Wendelboe indicates that Eyde corrected the proofs himself and exercised a free hand in presenting his own version. Birkeland wrote to Olaf Devik that he was very upset by this. On June 28, 1915, he sent a long letter to Aftenposten. An English translation of selected sections of Birkeland’s letter reads The exposition is so incomplete that it is entirely misleading. Regrettably I must raise objections. The core of our invention was created through tedious and persistent experimental work accomplished over several years under my leadership. Eyde was mainly responsible for administration. That is not mentioned in even a single line. . . . It states that the invention was due to lack of experience! The fact is, very few inventions have been made with more experience than the method for nitrogen production. . . . For a long time I fought, without noticeable support, for larger ovens to compete with the German method. Had I given up, Eyde, at best, would be sitting as the director of a German industry in our country. I hope that everyone now understands that my remarks here are necessary for an accurate history. Helwan, 13th June 1915 Yours sincerely, Y Kr. Birkeland

Wendelboe promised to correct the mistakes Birkeland pointed out, but never W did. In his 1939 autobiography, Eyde used nearly the same words that were attributed to Wendelboe in 1915. A signiﬁcant part of their disagreement centered on Eyde’s claim that during their ﬁrst meeting he had asked for “the biggest lightning in the world”. Birkeland insisted that he had asked for many small discharges similar to the method used by Bradley and Lovejoy in the United States. In fact, during their ﬁrst ofﬁcial meeting, Eyde gave Birkeland a copy of the paper by Bradley and Lovejoy, where they claimed to have solved the problem. In addition, Eyde claimed that at all times he was actively involved in laboratory tests. Birkeland argued that Eyde was responsible only for administration and maintaining ﬁnancial support (Figure 61). 7.4 MARCUS WALLENBERG Marcus Wallenberg (1864–1943), shown in Figure 62, belonged to the richest ffamily in Sweden and for a while was Governor of Stockholm. He was an uncle of Raoul Wallenberg (1912–1947), the Swedish diplomat who saved many thousands of Hungarian Jews from Nazi death camps during World War II and was later executed by the Soviets as an American spy. The Swedish capitalist

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Figure 61. A short excerpt from the discussions in Aftenposten regarding the discovery of the F Birkeland–Eyde method for fertilizer production.

provided funds from the family-controlled Stockholm Enskilda Bank, and obtained further ﬁnancing from the Bank of Paris. Sam Eyde was married to the Countess Anna Ulrika (called Ulla in Norway) Mørner. Through her he gained entr´e´ e to Swedish nobility and access to ﬁnancial circles. Wallenberg played a central role in establishing Norsk Hydro and was Chairman of the Board from 1905 to 1942. Thus, Norsk Hydro resulted from a fruitful collaboration between a university professor, an engineer, and a ﬁnancier. Most likely Eyde’s close connection to the Swedish nobility and the Wallenberg family explains why h the establishment of Norsk Hydro continued undisturbed while the Union between Sweden and Norway was dissolving in 1905. Wallenberg claimed that several times he saw a document signed by Eyde W stating, “the invention as well as the tests of the nitrogen method are due to Kr. Birkeland.” During the early years surrounding the establishment of Norsk Hydro, Eyde only referred to “the Birkeland method for the nitrogenfertilizer industry”. Wallenberg was willing to take an oath on that. However, that document was never recovered. Wallenberg felt certain that Eyde had purchased the document. In his 1960 book Stockholm Enskilda Bank Kring Sekelskiftet, Dr. Olle Gasslander discusses Marcus Wallenberg’s involvement with Norsk Hydro. He documents the great admiration Marcus Wallenberg and his family held for Birkeland. They were somewhat skeptical about Sam Eyde, especially his limited knowledge of chemistry and electrical engineering. Wallenberg never proposed, as has been written in some books, that Eyde should receive a Nobel Prize in Chemistry.

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Figure 62. Painting of Marcus Wallenberg. F

7.5 OTHER TECHNICAL APPLICATIONS Birkeland received a total of sixty patents relating to eight different ﬁelds, as listed in Appendix 3. Fourteen patents include another person, but Birkeland’s name was always ﬁrst. Forty-ﬁve of the patents originated between 1901 and 1907; the other ﬁfteen were granted between 1907 and 1913. One early patent is shown in Figure 63.

Figure 63. Copy of nitrogen furnace patent from 1903. F

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Figure 64. Birkeland’s ﬁrst X-ray tube and the photographic plate, at The Norwegian Technical F Museum, from the Norwegian newspaper Morgenbladet titled “De Røntgen’ske Straaler (R¨ntgen ¨ Radiation)” from March 25, 1896.

7.5.1 X-Rays By the end of 1895, all European newspapers were ﬁlled with articles about “a new kind of rays” discovered by Wilhelm Conrad R¨o¨ ntgen (1845–1923) ¨ [Uber eine neue Art von Strahlen, Wurtzburg, ¨ 1895]. Birkeland was very interested in rays that made “invisible things visible”. In early February 1896, shortly after R¨o¨ ntgen’s ﬁrst announcement, Birkeland presented a demonstration of X-rays at the University. Ole Fredrik Olden (1879–1963), a laboratory assistant who later became headmaster of Stavanger Katedralskole, recorded that Birkeland conﬁgured his equipment to make the ﬁrst X-ray photograph in Norway on February 15, 1896. A week later he gave a public demonstration that was advertised in newspapers. His enthusiastic audience could see the effects of the new rays. The same evening, Birkeland also demonstrated an artiﬁcial aurora. On March 25, 1896, he published a long article on X-rays. Olaf Devik later recalled that Birkeland had talked of experimenting with X-rays during his work with gas discharges prior to R¨o¨ ntgen’s ﬁrst announcement. Birkeland said “I saw the bones in my hand clearly and also showed them to Professor Schiøtz.” Unfortunately, we have no other source to verify this claim. Occasionally even Birkeland failed to pursue his ideas to their limits (Figure 64). 7.5.2 Atomic Energy In 1906, Birkeland sent two detailed letters to the Wallenberg brothers proposing to split the atom to create energy. This proposal was made several years before

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Figure 65. An excerpt from Birkeland’s letter to Bank Director Wallenberg, dated 7 April, 1906. F

Ernest Rutherford’s famous experiments showed that atoms consist primarily of empty space in which electrons orbit exceedingly small positively charged nuclei. It was also seven years before Neils Bohr (1885–1962) published his atomic theory. Birkeland had probably read Albert Einstein’s (1879–1955) 1905 paper on special relativity that ﬁrst derived the famous E = mc2 relationship between mass and energy. Birkeland’s letters to the Wallenbergs sought funds to conduct experiments over a two-year period at an estimated cost of 100,000 Norwegian kroner, in addition to his salary of 20,000 kroner. Marcus Wallenberg had been very active in ﬁnding the large sums of money needed for starting Norsk Hydro. In the letter (Figure 65), Birkeland wrote: The problem I propose to solve is to ﬁnd a practical way to utilize atomic energy. Our most important energy sources are stored in the molecules. . . . If we solve this problem, we can get more energy out of one kilogram of matter, than we get out of 100,000 kg coal today. y . . . I realize fully how difﬁcult the problem is and that perhaps I cannot manage it. However, I have never been so convinced to take something up, as I am with this problem.

Wallenberg realized that the scope of Birkeland’s idea was gigantic. However, W he declined to put money into Birkeland’s new project before he received some return from the fertilizer investment. After Wallenberg’s reply, no further speculation on atomic energy appears in any of Birkeland’s remaining documents.

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Figure 66. Spaceship propulsion experiment. Birkeland mounted a rotor in his vacuum chamber F to demonstrate that the cathode reaction pressure would move it smoothly.

7.5.3 Rocket Propulsion Birkeland and his assistants carried out several experiments that were never published. Olaf Devik told a story about their tests of spaceship propulsion. In June 1912, there was some discussion in French newspapers about the possibility of moving in empty space where there is nothing to push on. Birkeland at once concluded: “No problem, but the propulsion will have to be the reaction pressure from a cathode.” They put together the experiment shown in Figure 66. A simple rotor was mounted in the 320-l chamber. Cathode rays were emitted tangentially, and the rotor moved smoothly. Birkeland was very satisﬁed with the experiment, but did not discuss it in any of his works. He also predicted that future space missions would use reactive pressures on cathodes. This is similar in concept to magnetohydrodynamic thrusters.

7.5.4 Radiowave Propagation Before ﬁnishing his university degree, Birkeland was interested in radio applications and conducted several electromagnetic wave experiments at the University. There was a long break in these experiments between 1893 and 1906, when he resumed work with Morse code signals in telegraphs and telephones. w His main idea was to use the electric plasma torch as a transmitter circuit. The

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motions of the particles in the torch produced electromagnetic waves. During the year 1906–1907, he took out seven patents. Together with Sam Eyde and Marcus Wallenberg, he formed a small company called “Birkeland’s Patents in Wireless Telegraphy and Telephony”. Most of the work was carried out at the W University, where the company employed Anders Henrik Bull for three years starting August 1, 1906. Previously Bull had worked for the United States Navy in New York. Birkeland designed a radiowave transmitter and asked the University administration for permission to place a 15-meter antenna on the roof of Domus Media, promising to cover all project expenses. In spite of protests that the antenna would destroy the view and that the University should not be in the business of applied research, he received permission in June 1907. A receiver station was built at Frognerkilen, about 4 kilometers to the west of the University. Signal reception was clear. Birkeland’s radio propagation work drew signiﬁcant attention in Norway and abroad. In 1908 alone, his radio experiments were discussed in French newspapers eight times. Birkeland was unsatisﬁed with the results and planned to continue the experiments, but died before he could return to them. 7.5.5 Production of Margarine Norwegians were then active whale hunters. Birkeland took out a patent to produce margarine using whale oil. A large factory was planned in Sandefjord, the homeport of a whaling ﬂeet. Birkeland’s patent was widely accepted and discussed in the newspapers. However, at the last moment, a wealthy foreigner bought up most of the company shares and then refused to use Birkeland’s patent. During his stay in Egypt between 1913 and 1917, Birkeland worked on several projects for which he planned to secure patents. We describe three of them. 7.5.6 Hearing Aid Before turning 30, Birkeland suffered a serious hearing loss that worsened with age. He began experimenting with hearing aids and planned to take out a patent on the mechanical design in a letter dated August 9, 1915, to engineer A. Bryn, the head of the patent ofﬁce in Kristiania. The letter shows that he had submitted an earlier application to Bryn, but had not received a patent. After making some changes he resubmitted the application. In the accompanying letter, he wrote, “We will solve the problem related to the hearing aid as suggested in the enclosed sketch.”

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During the winter of 1915–1916, Birkeland considered making caviar out of cod eggs. He discovered that the Norwegian ﬁshing industry produced many barrels of cod eggs every year that were not used for human consumption. While in Egypt he came upon a recipe for making Turkish caviar. With adjustments to the recipe, he was convinced that excellent caviar could be made of cod eggs. He himself made several samples that he sent to friends for testing. No one claimed that he had discovered a useful product. However, a Norwegian ﬁrm expressed an interest in collaboration. Because of the war, the project never got underway. Several years ago Birkeland’s cod recipe was mentioned in a BBC program. 7.5.8 Radiation Treatment During his residence, Birkeland noticed that many visitors regarded the Sun’s radiation as helpful and came to Egypt in hopes of recovering from illness. Reﬂecting on this, Birkeland began to think that radiation from radioactive materials might be more effective. He then contacted Dr. Ellen Gleditsch, who had worked for Madame Marie Curie in Paris after completing her doctoral research. Ellen Gleditsch became an Assistant Professor of Chemistry at the University of Kristiania in 1915. Birkeland and Helland felt that the University had too many German-speaking scientists and in 1913 and 1914 worked hard to obtain a permanent position for her. In three letters, dated 1915, Birkeland suggested that they should collaborate on a patent for “a radiating shirt with secondary radiation from radio-active material”. He suspected that the intensity of primary radiation might be too high, but they could include reasonable ﬁlters. He looked forward to her comments. As World War I intensiﬁed, communications between Egypt and Norway became nearly impossible. We were unable to ﬁnd a reply from Gleditsch. Given present understanding of the connections between radiation exposure and cancer, this idea was best not pursued.

Part IV: Birkeland the Man

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Unfortunately, none of Birkeland’s coworkers or close friends wrote in any great detail about Birkeland as a person. Olaf Devik, Birkeland’s closest colleague during his last decade, gave one of the authors access to all the materials he had collected. This chapter is based primarily on Devik’s material, supplemented by comments of Professor Leiv Harang (1902–1971). We also searched through relevant archives in Norway (cf. Appendices 2–4). Birkeland’s contributions to science and technology were accomplished in a brief but hectic quarter century. By all accounts, he was tireless and extremely energetic. Simultaneous projects demanded that he work day and night, paying little heed to the impact on his health. His imagination was creative and lively with a sure instinct for synthesizing a wide range of information to solve scientiﬁc and technical puzzles. Over the course of his life, Birkeland came to enjoy both wealth and fame, but he never spared himself. When he did not receive the funding he requested from the government, he freely donated personal resources to pay for salaries and expeditions. He sought out and employed gifted young scientists such as Carl Størmer, Lars Vegard, Sem Sæland, Ole Krogness, Olaf Devik, Thoralf Skolem, Karl Devik, Claus T. Riiber, Anders H. Bull, and Carl F. Holmboe. All of them became giants of the geophysical, mathematical, or chemical sciences. Birkeland stimulated their interest in research with his creative imagination and sense of humor, especially about his own foibles. He introduced fundamental concepts and ways of looking at scientiﬁc information that were truly revolutionary. The Vice-Chancellor of the University characterized Birkeland as “A scientiﬁc explorer by the grace of God”. In some respects, Birkeland appears almost childishly na¨ve. ¨ Government support for his research drew the envy of some academic colleagues, but he found it difﬁcult to keep secrets, even his innermost thoughts. He often published his latest ideas before taking sufﬁcient time to consider their implications. Journalists frequently sought his opinions on controversial matters related to applied and basic research. He never held back and often found himself at the

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center of public controversies, but the intensity of his response to Størmer’s article in Aftenposten indicates that he disliked being attacked. Birkeland was absent-minded and disorganized in his daily life. He never kept notebooks but relied on memory. When University ofﬁcials once asked him to document expenses, he replied: “Why? I remember the sum.” When visitors called upon him, he would hurriedly jot notes on small slips of paper, then lose them. While he wrote a few letters to his assistants, telegrams were his preferred means of communication. He sent few personal letters to family and friends. Yet, despite his personal eccentricities, he was well respected by his many friends and devoted colleagues. He certainly did not ﬁt the stereotype of an aloof scientist devoid of human emotion. Elisar Boye’s death during the Haldde campaign affected him profoundly. 8.1 TEACHER AND EXPERIMENTER As a student at the University of Kristiania, Birkeland was unimpressed with the quality of the physics instruction. On returning from his studies at the great laboratories and research centers of Europe, he sought to implement practices he had learned while abroad. Entering the 20th century, Birkeland was determined to introduce changes into physics courses, but he found the University’s formal criteria too conservative, and his dedication to reform was not universally appreciated. His independent spirit did not submit easily to University regulations. Never hesitant to disagree with older professors, Birkeland often represented the minority opinion. The “boy professor’s” youthful appearance and his feisty reaction to criticism of his research fueled resentment. Also, many colleagues were irritated by his disorganized approach to work. Fortunately, Olaf Devik usually found diplomatic solutions to administrative and ﬁnancial problems. Birkeland’s lectures were always interesting and frequently surprising for his students, and the hall was usually ﬁlled. Between ten and twenty students completed Birkeland’s physics course each year, an unusually high number for the time. He was known as an excellent lecturer whenever the subject interested him. He would walk up and down the lecture hall, expounding on his views. And he loved to conduct demonstration experiments in the classroom, especially one that produced loud noises or bright electrical sparks. Olaf Devik attended his lectures in 1906 and 1907, and described them as follows: Birkeland had little time for lectures, but when he occasionally lectured on a subject that interested him, he brought a breath of fresh air into the classroom. Then, he would operate electrical equipment far beyond the rated capacity and burn out 100-Ampere fuses with digniﬁed nonchalance. Then he would stop with a hint of smile and, in a royal manner, untie the rufﬂes of his ermine jacket and dry his glasses in order to better see and continue his long equation on the blackboard.

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The last sentence also suggests that Birkeland was elegantly attired for his lectures. From 1903 to 1913, Birkeland had little time for teaching and paid substitutes to give his lectures. He bore such a heavy research load that the ViceChancellor agreed to his requests, especially since Birkeland personally covered the costs. Most surprising is the fact that Birkeland gave his regular lecture, in formal dress, to the students from ten to noon on May 15, 1905, his wedding day. Birkeland gave several lectures at The Norwegian Academy of Science and Letters. With the publication of NAPE Volume I and the continuing growth of Norsk Hydro, Birkeland had become so well-known that King H˚a˚ kon and his adjutant sat in the lecture hall’s ﬁrst row. The two lectures that drew the most attention dealt with his ideas about cosmogony Other Worlds in the Universe (January 31, 1912) and Creation of Our Solar System (March 8, 1912). They were published by the Aars og Voss High School in memoriam and replicated as long reviews in Aftenposten. Although Birkeland’s ideas and inventions intrigued the public, it is not clear from the manuscripts whether Birkeland thought his audiences could really grasp his concepts. This was probably the ﬁrst time anyone pointed out that electromagnetic forces play essential roles both in our solar system and in the universe. Translated into English, one quotation from his public lecture reads: To understand distances and dimensions in our universe, imagine our Sun is a grain of sand only one millimeter in diameter. In that case our Earth would be an invisible dust particle, ten centimetres away. The nearest star, Alpha Centauri, would be 20 km away. It is in this inﬁnite space, that all celestial bodies exist and are formed. . . . All matter in the universe, including us, is composed of ﬂying atoms that are continuously ejected from the Sun and other stars by electrical forces. These dust particles and the free charged ions and electrons, which may condense to form particles, are all transmitted from the universe.

In his description of the stream of charged particles, Birkeland, in 1913, used the phrase “the fourth state of matter”. These particles in turn condense to form larger spheres, ultimately planets that rotate around a central body because of gravity. This hypothesis is also important in his theory for the rings around Saturn, and clearly shows why he felt that electromagnetic forces were as important as gravity: New worlds emerge in space more frequently than human beings are born on Earth. Each world has its eclair ´ de nuitt—i.e. a ﬂash of light in dark space. But such glimpses of light disappear without any visible marks. It is therefore important that all human beings use their intelligence and thoughts to avoid ignorance. It follows that such worlds must die frequently, or more accurately, they are born and die in numbers that surpass our imagination.

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Shortly after the lectures, he published an article in Comptes Rendus called De l’origine des mondes. In slightly different form, this paper was also published in both English and German. At the time his hypothesis about the cosmic importance of electromagnetic forces received little international attention. In a later lecture to the Academy, Birkeland described when and how he ﬁrst came upon the ideas expressed in The Creation of Our Solar System. “I ﬁrst had the idea around 1910 that the creation of planets must have occurred by electric disintegration of distant stars and the formation of (spiralt˚ taker ) spit˚ ral clouds around a central body.” In this surmise, he was simply extrapolating from the electrical disintegration of cathodes observed in his terrella experiments. His intellectual interests were wide ranging. His derivation of a general solution of Maxwell’s equations demonstrates his mastery of the most difﬁcult ﬁeld of contemporary theoretical physics. The original and independent trend of his analytical capacity impressed everyone who read the publication carefully. His critical and analytical sense was, above all, creative. During his whole life, he was always active and vividly engaged, and he loved to throw out technical, theoretical, experimental, and practical ideas for consideration to people around him. In 1910, his mind was particularly focused on electric phenomena in the solar system and interstellar nebulae. Unfortunately, Birkeland never kept a diary. Important messages were noted on papers that were either left on his desk or put in his pockets and then forgotten. He did, however, possess an excellent memory. In later years, Olaf Devik maintained order in his administrative papers. Although Birkeland felt uncomfortable in the formally structured atmosphere of the University, he certainly had several trusted friends, particularly Waldemar Brøgger, Dean of the Science Faculty and Professor Fridtjof Nansen, Norway’s most famous citizen, together with the directors of the Solar Observatory and the Meteorological Institute (Figure 67). Birkeland published his work to inspire national pride and gain recognition for Norway. Actively involved with the referendum on independence, he strongly urged everyone to vote to end the Union. He contributed to a full-page announcement in Aftenposten urging all Norwegians to vote for a constitutional monarchy rather than a republic. If Birkeland sensed he was close to a breakthrough in resolving a speciﬁc problem, he worked feverishly until a solution emerged. For long periods, his eating became so erratic that his friends invited him to their homes for dinner. Sem Sæland wrote, “I never knew another man so engaged with science and with such reckless devotion. He worked far beyond the resources a human constitution can tolerate. It never occurred to him not to concentrate wholly on his work.”

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Figure 67. Photograph of Birkeland at his desk at the University taken around 1910. F

In 1904, Birkeland hired Carl Holmboe to work as an engineer on the absorption system. His 1948 book An Engineer Looks Back (En ingeniør ser seg tilbake) recounts, “We spent many pleasant evenings in front of the ﬁreplace, together with Birkeland. There he unfolded his brilliant knowledge, his view of the universe, his auroral theories and, not least, his opinion of life and mankind. He predicted the possibility of splitting atoms. The existence of ions, he said, demonstrates that atoms have the ability to limit and absorb electric charges, and thus they cannot be solid units.” Birkeland showed characteristics similar to those of Dr. Stockman in Ibsen’s famous play An Enemy of the People. Dr. Stockman was both intelligent and hard working. In spite of public resentment that destroyed his family ﬁnancially and politically, Stockman strongly advocated solutions to difﬁcult environmental problems. 8.2 BIRKELAND AS A POPULAR AUTHOR In addition to his scientiﬁc papers, Birkeland also wrote articles for the popular press, and reports about him appeared regularly in the newspapers. In 1898, Birkeland’s article Sunspots and Auroras: A Message from the Sun appeared on r Gang, one of Norway’s largest newspapers. This was the front page of Verdens the ﬁrst presentation of his new auroral theory to the general public. The incident that prompted the article was a large auroral storm on September 9, 1898, which was seen as far south as Rome. It is extraordinary to ﬁnd red auroral displays at these latitudes, a phenomenon that only occurs once or twice in a century. This event caused widespread fear among people who were not accustomed to seeing

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Figure 68. Title page of Birkeland’s article in Verdens F r Gang about the the big auroras and the magnetic storm on 9 September 1898.

auroral lights, and it was thought by many to be a celestial warning of impending tragedy. In fact, on that very night an Italian anarchist assassinated the Empress of Austria. Birkeland saw the intense auroral display and immediately contacted the Director of the Paris Astronomical Observatory asking about their solar activity observations. Records conﬁrmed the presence of several large sunspot groups that passed the Sun’s central meridian two days before the auroral lights were seen above Paris. Birkeland also contacted Norwegian telegraph operators who reported that communications had been interrupted for several hours. Birkeland’s title, A Message from the Sun, grabbed people’s attention, and the article provided an excellent opportunity to explain his auroral theory and to demonstrate the results of his ﬁrst laboratory experiments (Figure 68). During his stay in Sudan and Egypt, Birkeland published popular articles on science and travel. He described how much he liked bread made from durra grain and expressed concern for local people who experienced a tenfold increase in the price of durra between 1910 and 1914 (Figure 69). He gave a taste of the team’s living conditions writing, We rented a comfortable house with three bedrooms, a large balcony and an outhouse. I have furnished it in a simple manner. The house is located on the outskirts of Omdurman close to the desert. The wind is often so strong here that I, in contrast to my assistant, am not able to stay on the roof of our house, but instead observe from a site in the desert.

He also wrote about how important his household servants were in helping take care of daily life and keeping the house secure. Although, he only needed the help of two young boys, as an act of charity, he hired four servants, and eventually agreed to pay for seven. The governor of Omdurman advised Birkeland to buy a gun, the ﬁrst he ever owned. Although he had some military service, he knew little about ﬁrearms. Public health conditions drew special attention.

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Figure 69. Photograph of Birkeland in Omdurman, Sudan surrounded by children and local F people. He was popular for showering them with small gifts. To my horror I saw that Omdurman had many lepers who are not kept isolated, but live among other people and even eat from the same pans. Several of the sick are allowed to serve as water porters in the town. Close to our house is a public water well where a leprous woman works. I saw adults and children drinking her water.

8.3 POSITIONS AND HONORS Both as a student and after graduation, Birkeland worked part-time as a highschool teacher and private tutor. In 1891 and 1892, he was a teacher at the Aars og Voss High School. At the age of 26, he was appointed to the permanent position universitetsstipendiat in physics at the University. Three other candidates had competed for the position. The salary, though not high, was sufﬁcient for him to live on. More importantly, the appointment gave him a ﬁxed working place within the University. In October 1896, at the age of 27, Birkeland was elected a member of The Norwegian Academy. In the Academy’s 150-year history, only Fridtjof Nansen, at 26, was elected at a younger age. In October 1898, King Oscar II of Sweden and Norway called Kristian Birkeland to be Professor of Physics. He was then 31 years old, the youngest member of the Science and Mathematics Faculty at The University of Kristiania.

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The average age for new professor appointments was 42 years. At the time, he looked much younger than his actual age and could have been mistaken for a student. For a few years, he was referred to as “The Boy Professor”. For the ﬁrst time in its history, the University of Kristiania had two Professors of Physics. His position was called “a movable professorship”. On the death of a professor of Religion and Philosophy, Birkeland was offered his chair. He obtained this prestigious appointment just eight years after completing his university degree. An appointment by the King offered a very secure civil-servant position. Every new professor was required to give an introductory lecture, and many people were surprised that Birkeland’s lecture concerned his solar-radiation discoveries rather than auroral theory. In 1906, Birkeland was elected a Fellow of the Faraday Society in London. In 1908, he received an honorary doctorate, Doktor-Ingenieur Honoris Causa, from Dresden Technical University. The same year he was also elected a member of Royal Society of Arts in London. 8.4 NOMINATIONS FOR THE NOBEL PRIZE The Nobel Prize is the most prestigious award that a scientist can receive. While Birkeland never won the prize, the Nobel Archives show that he was nominated four times each in physics and chemistry (cf. Friedman F , 2001, The Politics of Excellence). Multiple Nobel Prize nominations bear witness to the P wide appreciation that Birkeland’s work gained outside Norway. Members of the Royal Swedish Academy of Sciences are entitled to nominate candidates. The ﬁve members of the Nobel Committees for Physics and Chemistry are either previous winners or professors from universities in Denmark, Finland, and Norway in those ﬁelds. The committees may also ask the Academy to invite selected individuals to submit nominations. The committees evaluate nominations, prepare reports on candidates’ merits, and make recommendations to the Academy. The Academy’s physicists and chemists then vote to approve the proposals or make their own recommendations. Finally, the full Academy votes. Although the prize was established in 1901 and was thus fairly new, it had already become very prestigious. Birkeland had clearly done outstanding work in fertilizer production with his plasma torch. It was reasonable for him to be nominated for developing a process to synthesize nitrogen-based fertilizers and starting Norsk Hydro. His patents offered real solutions to the global fertilizer problem, even though few other nations could utilize his method without cheap hydroelectric power. Since Sam Eyde succeeded in naming the process Birkeland–Eyde, it is understandable that he wanted to be included in the nomination.

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8.4.1 Nobel Prize in Chemistry Professor Birkeland, alone or together with Director General Sam Eyde, received four nominations for the Nobel Prize in Chemistry: 1907: Birkeland and Eyde. Nominated by Professor Max Bamberger, Wien University. 1909: Birkeland and Eyde. Nominated by Professors W. C. Brøgger, J. H. Vogt, and H. J. Goldschmidt, University of Kristiania. 1912: Birkeland. Nominated alone in one proposal. Nominated with O. Schonherr ¨ in another proposal. 1913: Birkeland and Eyde. Nominated by Professors W. C. Brøgger, J. H. Vogt, and H. J. Goldschmidt, University of Kristiania. Between 1907 and 1913, about ﬁfteen well-known scientists were proposed for the Nobel Prize in Chemistry. It would have been extraordinary for Birkeland, but even more so for Eyde, to receive a Nobel Prize. Eyde launched an unsuccessful campaign with the Nobel committee to obtain the prize. However, most committee members recognized his limited experience in chemistry and electrical engineering. A letter of Ragnar Sohlman, the Director of the Nobel Institute, quoted by Friedman F (2001), indicates that, if Birkeland had been nominated alone without Eyde, he probably would have received the prize. The committees appreciated the fact that the scientiﬁc basis for the technical fertilizer method was Birkeland’s invention. Professor Peter Klason, a member from 1901 to 1925 and twice chairman of the Nobel Committee in Chemistry, repeatedly tried to secure a prize for Birkeland or Birkeland and Eyde. However, committee majorities rejected his efforts, claiming that the Birkeland–Eydeprocess did not provide a deﬁnitive solution to the problem. Friedman F (2001, p. 104) writes, “Complicating the matter yet further were Klason’s poor tactics. He shifted position often, one year backing the Norwegians, then only one of the partners, then one year the Germans. Perhaps some committee members were hoping for a Swedish breakthrough in ﬁnding a successful process.” When Birkeland was nominated alone in 1912, Eyde and his cousin, Alf Scott-Hansen, were very upset when they heard about this single nomination. After all, it was Eyde’s money that had enabled Birkeland to develop the furnace. At the time they felt that if Eyde were not included in the nomination, it would be better if Birkeland did not receive the prize. However, in his autobiography, Eyde (1939) argued that it was scandalous for Birkeland not to receive a Nobel Prize in Chemistry. Some books have suggested that Marcus Wallenberg was involved in the campaign in favor of Eyde with the Nobel committee. This cannot be documented and seems unlikely. Wallenberg wrote: “Knowing Eyde’s lack of knowledge in chemistry and technology, I was surprised by his

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nomination, but Birkeland deserved a prize” (Gasslander, 1960). It is uncertain whether Birkeland ever knew that he had been nominated for the Nobel Prize w in Chemistry. 8.4.2 Nobel Prize in Physics Birkeland, alone or together with Carl Størmer, also received four nominations for the Nobel Prize in Physics: 1915: Birkeland and Størmer. Nominated by Professor Vilhelm CarlheimGyllenshøld. 1916: Birkeland. Nominated by Professor O. Pauersson. 1916: Størmer and Birkeland. Nominated by Professor Vilhelm CarlheimGyllenshøld. 1917: Størmer and Birkeland. Nominated by Professor Vilhelm CarlheimGyllenshøld. 1918: Birkeland. Nominated by four Norwegian professors; but not forwarded to Stockholm because of Birkeland’s death in 1917. Professor Vilhelm Carlheim-Gyllenshøld was a Swedish member of the Nobel Committee in Physics from 1910 to 1934. Through his cosmological research, he understood the theoretical work of Birkeland and Størmer very well, and he nominated them because their work breathed new life into the age-old riddle of aurora borealis. Thus, Birkeland was nominated not for his theoretical and experimental work related to charged-particle radiation from the Sun and other cosmic phenomena, but for his auroral work. The nominations by CarlheimGyllenshøld raised concerns among several committee members who considered cosmic physics to be part of astronomy, and thus beyond the boundaries established for the Nobel Prize. Also, few members of the Academy felt qualiﬁed to evaluate the merits of the candidates. However, they recognized that cosmic physics had a strong heritage in Swedish research although it did not have the formal status of a department in any university. The special report on the Norwegian researchers argued that since no department of cosmic physics then existed in Sweden, a thorough examination of their results could not be made.

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9.1 BIRKELAND’S HEALTH Exercising and taking regular meals as a way to stay healthy was a foreign concept that seldom, if ever, crossed Birkeland’s mind. He always worked hard and was rather careless in his eating habits. His assistants frequently had to remind him to eat lunch. Signiﬁcantly, he often complained of insomnia, apparently a long-term problem. In his letter of February 13, 1893 from Paris to Vilhelm Bjerknes he complained that he could not sleep. During the Haldde campaign he volunteered to take the nightly sensor readings because of insomnia. He also had difﬁculty with his hearing. Before ﬁnishing his university degree and in the following two years, Birkeland tried to replicate the experiments that Heinrich Hertz conducted during the 1880s on the generation and propagation of radio wav a es. His lab equipment was in the cellar beneath the University Library. He later explained to his assistants that this work was the source of his hearing problems. Dessler (1983) suggested that Birkeland might have suffered from chronic mercury poisoning. Indeed Birkeland often changed his experimental conﬁgurations and needed movable feeds to his discharge tubes. They used mercury as the sealant. Through exhaust from the vacuum pumps, Birkeland certainly was exposed to mercury vapor, as were most of his assistants. Mercury poisoning progressively affects motor control areas of the human brain, and trembling hands are one symptom of mercury poisoning. This book provides samples of Birkeland’s handwriting between the ages of 18 and 49 that show that his hands grew more unsteady with age. However, Birkeland was not exposed to mercury pumps during his last four years, yet his problems with shaky hands persisted. With the assistance of a physician, we examined samples of Birkeland’s handW writing at various stages of his life, but ﬁnd no obvious conﬁrmation of the mercury-poisoning hypothesis. Dessler also claims to see mercury poisoning effects in a lowered quality in the style of his writing in his last years. We examined Birkeland’s last publication from early 1917 in which he compares zodiacallight variations observed simultaneously in Rhodesia and Egypt. The paper is a model observational report that summarizes different opinions of contemporary investigators and their consequences for understanding his measurements.

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One might argue that zodiacal light was a less interesting topic than auroral physics. However, given Birkeland’s interest in heliospheric physics, this does not indicate chronic mercury poisoning. In The Northern Lights Jago describes a physical collapse that Birkeland experienced in February 1905 while working on the nitrogen-ﬁxation project. His concerned housekeeper contacted Tønnes who diagnosed his brother as suffering from nervous exhaustion. On the advice of a local pharmacist, Tønnes prescribed a new drug called veronal to help him overcome insomnia. Chemically veronal is a member of the barbiturate family. Apparently it was then regarded as safe to use, but in the following decade, as doctors came to understand its side effects, the British government made veronal a controlled substance. Elsewhere it was readily available at pharmacies. Barbiturates are still prescribed to help overcome insomnia and mitigate epilepsy by reducing the sensitivity of the brain to high electrical activity. Veronal can also act to suppress brain activity in the respiratory center, especially if taken with alcohol. To manage ongoing bouts with insomnia, Birkeland used veronal for the rest of his life. As we shall see, veronal was physically responsible for his death 12 years later. Understanding the genesis of his use of the substance is thus interesting. However, we have been unable to ﬁnd documentary evidence for either a physical breakdown in February 1905 or for his brother’s traveling a full day from Porsgrunn to provide medical assistance. Sem Sæland claimed that Birkeland’s decision to take up residence in Egypt was motivated by the development of a heart problem. Birkeland carried a good deal of medication with him from Norway. Unfortunately, in the long run, the warm weather of Egypt and the company of his two young research assistants failed to provide the relief he sought. Sleeping problems persisted. Since he worked such long days, the insomnia made him more nervous and edgy. Birkeland also suffered several “shivering attacks” and found it difﬁcult to enjoy walks outdoors. As his health deteriorated, he experienced kidney pains and grew allergic to insect bites. Dr Louis Roeder was the physician for many Scandinavians living in Egypt, including Birkeland. However, no available correspondence indicates that Roeder ever gave Birkeland a thorough physical examination. By early 1916, after Karl Devik left for Norway, Birkeland felt increasingly homesick and ill, as expressed in several letters to friends back home. He felt that “Norway is the most beautiful country in the world, as long as one does not have to spend winter there. Summer here is even worse for my health than winter there. . . . In winter there is no place more lovely than Helwan, but you can’t imagine how terrible it is for my health in summer.” He suffered rheumatism because he could not protect himself from the heat. Birkeland also became increasingly paranoid and suspicious, partially because

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of the loss of contact with friends in Norway. He became increasingly fearful of the Egyptians around him, and was even convinced that his patent on the electromagnetic gun drew military espionage agents to his home. Feeling insecure in his new home he bought two guard dogs and two new guns. Soon he felt that he could not even trust his servants and dismissed them all even his housekeeper. Most of the information we have about Birkeland’s health during his last year is contained in a letter from Consul Eriksen’s wife, Gerda, and in the writings of Professor Terada. The letter by Gerda was written to Karl Devik in January 1918, half a year after Birkeland died, and describes Birkeland’s health during his last three months in Egypt in the spring of 1917. Terada’s writings come from shortly after Birkeland’s death as well as much later. In the latter case, he chose the literary form of a short story because much of what he wrote depended on memory. 9.2 MARRIAGE AND DIVORCE In his earliest years at the University, Birkeland became a close friend of Professor Henrik Mohn, the ﬁrst Director of the Norwegian Meteorological Institute and founder of meteorological science in Norway. Although Mohn was more than 20 years his senior, he consistently supported Birkeland’s applications for research grants, and he often lent him instruments for his expeditions. On many occasions Birkeland was invited to Mohn’s home for Sunday dinner. Both Mohn and his wife came from big families, and relatives often visited the professor’s home. On one of these occasions Mohn’s niece, Ida Charlotte Hammer, daughter of his sister Justine, caught Birkeland’s eye. She had actually met him several times before at family gatherings and even remembered how proud the boy had been of his magnet. Before 1901, he seems to have paid no attention to her. Ida was four years his senior. She had spent time in America and England where she studied cooking and worked as a teacher. Certainly Ida was intelligent, independent, and a devout Christian. Her father was a pastor in the Norwegian State Church. Beyond this, we know little about her. The main sources are Olaf Devik’s archives and Lucy Jago’s writings in The Northern Lights. Kristian Birkeland and Ida Charlotte Hammer were married in May 1905. A church ceremony was the only legal way to marry in Norway at that time. One well documented fact about their wedding day is that Birkeland gave his regular lecture to students that morning. A horse-drawn carriage was waiting for him outside the University. Thus, he came to the University in full formal dress, with shirt, cravat, and high hat. As usual he had to write a lot of equations on the black board, and he carefully tried to avoid getting chalk dust on his suit. Olaf Devik concluded that this was the ﬁrst time a University professor

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Figure 70. Birkeland’s villa at Incognitogaten 15 is located just behind the royal castle and close F to the University.

gave a regular lecture on his wedding day. Students thought Birkeland was less focused than usual. In the fall of 1900, Birkeland purchased his ﬁrst apartment in Lysaker, but he only lived there for one year. His second apartment at Drammensveien 45 was much closer to the University. He never sold it. In 1906, a year and a half after his marriage, Birkeland purchased an expensive (60,000 kroner) villa at the corner of Incognitogaten 15, a perfect location just behind the royal castle and a 10-minute walk from the University. It had white walls, arched windows, and a tower one story higher than the rest. The house was large with many bedrooms and an elegant dining room, where he and Ida could entertain as many as 24 guests. Birkeland bought expensive furniture, paintings by contemporary Norwegian artists and other furnishings such as vases from Japan and China. Whenever scientists visited him at the University or in connection with business at Norsk Hydro, Birkeland invited them to stay at his home. Today this building belongs to the Swedish Embassy (Figure 70). May 1905 was the most hectic time in the development of the fertilizer project, and there was no time for a honeymoon after the wedding. Birkeland brought his bride to his work place in Notodden. According to Devik, the marriage between Ida and Kristian never functioned very well. They formally separated in 1909 but had stopped living together well before then. Devik’s archive contains the settlement written by Birkeland’s lawyer, Johan Bredal. In the document, Birkeland states that Ida was blameless. All fault and responsibility for the divorce rested entirely on him. He asked Bredal to provide for his wife generously because he was concerned for her welfare. In Norway at the beginning of the 20th century, divorce from a well-known person drew

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much unwanted attention, particularly for the daughter of a pastor. The ﬁnal settlement placed the interest from a trust into her account, giving her a minimum of 5,000 kroner per year (equivalent to the current annual salary of a senior professor) for as long as she lived and remained unmarried. Ida was free to take anything she wanted from their house and keep all gifts she had received from Birkeland. Thus, Birkeland took good care of Ida ﬁnancially. Both parties signed the divorce decree on January 11, 1911. Ida, who never remarried, died in 1926. After the divorce, Birkeland worked even longer days at the University. 9.3 SOJOURN IN EGYPT After publishing the second volume of NAPE in 1913, Birkeland decided to move to Egypt for health reasons. The combination of overwork in publishing Volume II of NAPE, the conﬂicts with Eyde and Størmer, and his failed marriage had exhausted him. Moving to warmer latitudes until he recovered his strength was an attractive option, and Egypt offered a desirable climate. He had spent a few months there in 1910, although his actual measurements were made in Sudan. Once he made the decision it did not take long to complete his departure arrangements. Birkeland secured a leave of absence from the University to do research in Egypt that allowed him to receive his full salary for one year. Olaf Devik remained at the University where he was responsible for continuing terrella experiments, as well as maintaining correspondence and ﬁnancial records. Daniel Isaachsen (1859–1940), who was then an associate professor at the Naval Academy and soon became director of the Department of Weights and Measures, gave his physics lectures. Birkeland asked two assistants to accompany him, Karl Devik, an engineer who worked in the terrella laboratory, and Thoralf Skolem, a gifted mathematician who helped with Volume II of NAPE. Birkeland felt sure they would uncover interesting theoretical problems related to zodiacal light. They arrived in Alexandria in October 1913 and settled in Helwan, a small town about 30 kilometers south of Cairo. Helwan is the site of the Khedivial Astronomical Observatory which is in the mountains, seven kilometers from the railway station. Khedivial Observatory was Egyptian-owned, but was run by the British Survey Department who used it mainly for studies of the night skies. During Birkeland’s stay the director was Harold Knox-Shaw, a recent graduate of Cambridge University. Birkeland’s visit had been arranged with the secretary of the Royal Society, Arthur Schuster. Although Birkeland realized it would be hellishly warm in the summer, he was determined to have his headquarters at Helwan. Soon after arriving, they continued by train to Omdurman, Sudan where they replicated the experiments of 1910. Within a year of his arrival in w

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Figure 71. Kristian Birkeland dressed from head to toe in a prophet’s costume with a turban and F glittering galabiyya g . Karl Devik took the photograph in Omdurman, Sudan, during the spring of 1914. He wrote: “The turban is from Mecca and written in Arabic silver letters are the words ‘The Prophet’, in Norwegian, so as not to insult the local people.”

Egypt, Birkeland published his ﬁrst preliminary papers about zodiacal light in Comptes Rendus and in The Cairo Scientiﬁc Journal (Figure 71). Many Europeans came to Helwan seeking respite in a healthy climate. In the spring of 1914, Birkeland and his assistants attended a classical piano concert which had been advertised on the bulletin board of their hotel in Helwan. w Birkeland enjoyed classical music and was much taken with the performer, a pale, slender woman from Greece called Miss Hella Spandonides, probably then in her mid-thirties. Her given name was similar to the name of her country which is “Hellas” in Greek. Birkeland found her an accomplished pianist and w told her so after the concert. She told him that she was in Egypt seeking a cure from tuberculosis and only gave concerts upon request. Birkeland was fascinated by Hella Spandonides and, based on letters to his friend Amund Helland (1846–1918) in Norway, had fallen in love with her. She and Birkeland remained at the same hotel for a few months, and they

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enjoyed each other’s company. Hella knew Helwan and its surroundings and helped her Norwegian friends with practical matters, such as looking for a house conveniently located near Khedivial Observatory that was large enough to contain a laboratory. On several occasions, they went on shopping trips to the markets of Cairo. Hella returned to Greece when the war began. According to a letter Birkeland wrote to her, they shared many interests, and he wrote, “I am experiencing my life’s greatest adventure here.” He used less emotional language in a letter to Helland from the same period. Jago (2001) cites several letters from Hella to Birkeland, mailed from Greece, in which she speaks of missing their interesting discussions and small trips. Unfortunately, Olaf Devik’s archive and the other sources listed in Appendix 2 contain only one handwritten letter from Hella to Birkeland, dated November 22, 1915. She wrote of sending him several books, of her good health in spite of the cold and soul piercing winds, and her plan to return to Egypt after giving a concert later in the month. Alluding to a recent note from Birkeland, she offers condolences that some unspeciﬁed element of his research failed to work out as he planned. He should not be too upset, plenty of time remained for new accomplishments. “We are going to live 200 years!” After World War I broke out in August 1914, Egypt became a British protectorate. Skolem had to return immediately to Norway for military service before traveling became too difﬁcult, but Birkeland did not consider leaving at that time. Before departing, Skolem asked if he could continue to work for Birkeland in Norway. Birkeland proposed that Skolem ﬁnish the manuscript he wrote at the age of 18 for publication in France. It was published early in 1915 as a joint paper entitled Une m´e´ thode e´ numerative ´ de la g´eometrie ´ . In the summer of 1915, after Skolem ﬁnished military service, Birkeland sent a note requesting that he return to continue work on the zodiacal light in Egypt. Although Skolem wished to continue the project, he wrote that travel in Europe had become so uncertain, that for the time being he had little choice but to work at home. Over time Birkeland and Karl Devik became close friends. In published articles and in his letters Birkeland acknowledged Devik as “my indefatigable assistant and friend.” Birkeland discussed with him all endeavors, scientiﬁc and personal. Working conditions grew more difﬁcult after the war started, but they were able to carry out most of their observations. Devik was eventually forced to return to Norway for military service in February 1916. Outdoor zodiacal observations stopped after his departure. With both assistants gone, Birkeland continued his research at the Observatory, trying to improve the sensitivity of his photocell sensor in order to obtain statistically meaningful variations of zodiacal light. Although the English engineers were happy to help him, Birkeland basically worked alone. Lonely, Birkeland missed Karl who had become like a son. More and more Birkeland thought of home and

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his friends and started to write regular letters. In the ﬁrst two years he had mainly used telegrams. Now, he needed news from Norway, but as his need grew so, too, did problems with the postal service and wartime censorship. Postal messages were lost with increasing frequency. When his letters went unanswered, he complained about the lack of news. He received only one letter from Karl after his return to Norway. In it he writes, “My service with the King’s Guard has been so hard that it has been impossible to work at the terrella laboratory with my brother. Also, there are problems with electricity during evenings. . . . When I ﬁnish my military service, I will work full time to carry out the terrella experiments you proposed before I left” (Devik archive). In the absence of his assistants, Birkeland contacted the Norwegian consul in Cairo, but was very disappointed with the quality of help and advice he received. He was more successful with the Danish consul, Dr. Justinius Eriksen, and his wife Gerda, who was of Norwegian descent. Eriksen was born on April 13, 1862 in Vejle, Denmark. He earned his doctorate in opthamology from the University of Copenhagen in 1893. After divorcing his ﬁrst wife in May 1907, he married his assistant, Gerda Thomsen, in July. Gerda, who did not change her surname, held a master’s degree in medicine. They moved to Cairo in 1908 where they worked together as opthamologists. In 1911 Eriksen was designated the Danish vice consul in Egypt and three years later was promoted to full consul. The position was honorary so he continued to earn his living as an opthamologist. He died in Cairo on November 18, 1918 (Den ( Danske Læge Stand, p. 179, 1960, Jacob Lunds Forlag, København). Tired of living in hotels, Birkeland bought an elegant villa in Helwan in the fall of 1915. The value of this house was later estimated in his will to be 60,000 kroner. The Eriksens helped with the extensive paperwork required for the purchase. Owning his own home offered Birkeland greater freedom for his research. We have several photographs of him wearing a white tropical suit standing on the veranda of the house with a pith helmet. After rejecting several suggestions he ﬁnally christened it V Villa Mea (my home). Birkeland purchased elegant furniture and began to remodel which required building materials and Egyptian carpenters whom he feared over-charged him. Even before the interior of the house was completed Birkeland started building a new laboratory in a separate garden house. He made frequent trips to Cairo to ﬁnd things needed for “my new observatory.” Through the summer of 1916, Birkeland’s letters to friends in Norway were ﬁlled with optimism about his new home (Figure 72). 9.4 DEATH IN TOKYO The circumstances surrounding Birkeland’s departure from Egypt and subsequent death in Tokyo are veiled in mystery. The main sources of information

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Figure 72. Drawing of Birkeland’s new home in Helwan. F

about these events are a letter from Gerda Thomsen written to Karl Devik on January 15, 1918, a letter to Carl Størmer from Professors Nagaoka and Terada, Terada’s diary, and Terada’s short story, Death of Professor B, published shortly T before his own death in June 1935. We have found new documents related to Birkeland’s last six months that, to the best of our knowledge, have never been published. Analysis of their contents allows us to reconstruct events to a level of detail that was not previously possible. These documents come from several sources, primarily Olaf Devik’s archive that contained personal letters and receipts that Ambassador Peder Bernt Anker shipped back to Norway after the war ended. The second source consists of all the Birkeland-related entries in Terada’s diary in May and June 1917. These documents will stimulate different T degrees of interest among general readers and professional historians. For this reason, we replicate the new documents in Appendix 4 and summarize the ﬂow of events in the text. We cite documents supporting our reconstruction of events as we proceed. After the departures of Skolem and Devik, Birkeland’s loneliness intensiﬁed and his health deteriorated. In December 1916 Birkeland wrote to Helland, “Independent of what happens, I will not spend another summer in Egypt.” He wanted to celebrate his 50th birthday in Norway. Around New Year’s Day 1917, the physician for Scandinavians in Egypt, Dr. Roeder visited Birkeland at Helwan and found him in a state of paranoid collapse, convinced that British

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spies had him under constant surveillance seeking opportunities to harm him. Concerned, Roeder requested that Gerda Thomsen (Mrs. Eriksen) accompany him to visit Birkeland the next day. In her letter to Karl Devik, Gerda described Birkeland as exhausted, terribly thin and paranoid and identiﬁes the cause as “the abuse of coffee, too much work, whisky and veronal.” Gerda persuaded Birkeland to move to a guesthouse near the Danish consulate in Cairo where they nursed him back to health. By February, Birkeland’s health and good humor had returned, but his desire to return to Norway was still strong. Because World War I was raging in Europe, travel via the usual route through England was impossible. Gerda suggested a more circuitous route through the Far East and Russia. Birkeland brightened at the thought but was reluctant to make the journey alone. Since her husband had been considering a trip to Copenhagen, Gerda suggested they travel together. Birkeland was delighted and arrangements were hastily made. They left Cairo on March 10 and traveled by boat through the Suez Canal and across the Indian Ocean to Colombo, reaching Singapore in early April. According to Gerda’s letter, the initial stage of their trip went well, “They had an enjoyable voyage.” However, her statement that his paranoia had vanished, “After Colombo, spies were no longer mentioned”, was apparently less accurate. On April 4, 1917, Birkeland wrote a letter to his friend and conﬁdante Kaja Geelmuyden from the ship as it sailed between Colombo and Singapore. He alludes to his passage from Egypt as an Odyssey. After reaching Norway, he hoped to conﬁde in trusted friends to help understand what had happened to him. Singularly, he cites French agents as the source of his hardship. “My impression is that I have undergone much suffering through the fault of France, the country we have loved the most since our childhood.” (cf. Appendix 4). In similar complaints to the Eriksens, Terada and Nagaoka, his assumed oppressors were British. Birkeland and Eriksen reached Tokyo in early May and soon contacted Peder Bernt Anker, the Norwegian Ambassador to Japan. Eriksen informed the ambassador that Birkeland had been seriously ill while living in Egypt. Although their initial plans called for a 10-day stay in Japan before heading on to Vladivostok, Birkeland and Eriksen seem to have gone their separate ways at this point. Birkeland checked into the Imperial Hotel on May 7. Receipts indicate that he stayed there until May 12 before spending two days at Hakone, a famous f resort about 150 kilometers southwest of Tokyo. He came back to the Imperial Hotel between May 14 and 16 and then returned to Hakone as a guest of Ambassador Anker until May 27. Ambassador Anker signed the guest book at Hakone during 10–14 May 1917. We can document two things that Birkeland did during his stay at the Imperial Hotel. First, he refurbished his wardrobe by ordering a new suit, three silk shirts, and an overcoat from tailors at the T. Chang Shing Company near the Imperial Hotel. Receipts indicate that

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the suit and coat were completed by May 20 and June 8, respectively. Second, he made a ﬁrst, unannounced contact with Japanese scientists at the University of Tokyo. At least one pre-Hakone contact is mentioned in Gerda’s letter (January 18, 1918), Terada’s ﬁrst description of Birkeland in Death of Professor B (June 1935), and is alluded to in a letter of Professor Nagaoka (May 24, 1917) to Birkeland at Hakone. In The Death of Professor B T Terada describes an unexpected encounter with Birkeland in early May 1917 when Birkeland paid an unannounced visit to the University of Tokyo to check references in NAPE. Terada recognized him immediately because he had visited Birkeland at the University of Kristiania in the summer of 1909 and been invited to tea at his home. Obviously Birkeland’s reputation in auroral and geomagnetic research had reached all the way to Japan. However, in describing their meeting on this occasion Terada wrote, “It seemed to me that Professor B. could not remember me at once.” His impression was that “Professor B did not seem well, and seemed restless when talking with his acquaintances” (cf. Appendix 4). Later Terada informed Professors Nagaoka and Tanakadate of Birkeland’s visit but did not record the event in his diary. In the meantime, colleagues of Dr. Eriksen, whose opinions he respected, persuaded him that even if he were lucky enough to reach Copenhagen, it would be impossible to return to Egypt until the war ended. Wartime chaos had reduced the Russian government to near collapse. The probability of two safe passages across the vast Asian landmass via the Trans-Siberian Railroad was very low. He thus decided to change his plans and return to Cairo via Kobe and Shanghai. Birkeland probably received similar advice and eventually changed his itinerary as well. In a letter from the Fujiya Hotel in Hakone to his travel agency dated May 18, 1917, Birkeland cited a serious case of bronchitis as the reason for his change of plans. He redeemed his prepaid ticket and received a refund. The letter also mentions that Dr. Eriksen had decided to return to Cairo because of the war. Evidently, Birkeland planned to spend at least a few months in Tokyo because he also sent a telegram asking Karl Devik to come work with him. On the same day, Dr. Eriksen wrote a letter from the Hotel Pleasanton in Yokohama inquiring about Birkeland’s travel plans and providing his itinerary for the next few days in case Birkeland wanted to contact him. Even as he was leaving Japan, Eriksen was still unclear about Birkeland’s plans, but did provide him with the name of the charg´e d’affaires who was willing to help Birkeland arrange further travel. From the Hakone resort Birkeland sent a letter to Terada informing him that he would be staying in Japan and would like to visit him at the University. A few days later he asked for advice on ﬁnding a quiet hotel in Tokyo, not far from the University. Terada recommended the Hotel Seiyˆoˆ ken near Ueno Park within walking distance of the University. (This hotel burned in 1944, and a

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modern restaurant now stands in its place.) The Dean of the Faculty, Professor H. Nagaoka, also wrote to Birkeland expressing their pleasure at receiving a visit by such a famous researcher and the disappointment of the University’s Rector at missing him during his previous visit. Nagaoka arranged for Birkeland to meet the University’s Rector and invited him to give a lecture on any subject of his choice to the physics students and faculty. Differences between Terada’s diary entries and his short story written years later become problematic in determining the exact sequence of events surrounding Birkeland’s death. According to Terada’s diary, Birkeland visited him at the University on May 29th, the day after checking into the Seiyˆoˆ ken Hotel. Terada presented Birkeland with a copy of a paper he had recently written about geomagnetism and asked for his comments. On May 30th, he writes that Nagaoka visited Birkeland at the Seiyˆoˆ ken Hotel in the morning and was alarmed by Birkeland’s erratic behavior. His paranoia about the British government had returned in full force, and Nagaoka even feared that Birkeland was suicidal. Terada himself went to the hotel on the morning of May 31 and arranged to have T Ambassador Anker’s doctor examine him. Receipts dated June 4 and 5 from Dr. John Mann support this statement. Leaving Birkeland sleeping, Terada left for the University, but returned in the afternoon with Dr. Miura of the University medical faculty. Miura diagnosed Birkeland as “having been poisoned by a large number of sleeping pills.” After the others left, Birkeland told Terada a long story about his troubles in Egypt and that a British agent had been watching him even at Hakone. The conversation ended with Birkeland’s saying, “I am too tired. So I took eight tablets to ﬁnish them all” (Appendix 4). Terada’s diary entries from June 1 to 9 indicate that Birkeland quickly recovT ered from the veronal overdose of May 30 and visited Terada at the University several times to discuss physics issues and borrow documents. No diary entries for the following week concern Birkeland. On the morning of June 15, Terada was urgently summoned to the Seiyˆoˆ ken Hotel. In The Death of Professor B T Terada’s sequence of events is markedly different. There Terada wrote that after settling in at the Seiyˆoˆ ken Hotel, Birkeland “often visited me in the Physics Department.” Most likely these are the visits that Terada mentions in his diary entries of 1–9 June. We believe that the events recorded in the diary for May 31 most likely correspond to the long episode in Terada’s short story that begins “One day he asked me to come to his hotel because he had something to tell me that would take some time.” In the story, Birkeland was in bed in pajamas and insisted that they speak French rather than English or German which Terada understood more easily. The story took Birkeland more than an hour to relate. Relieved of his burden he fell asleep, and Terada returned to the University. In Death of Professor B Birkeland’s confesT sion preceded his death by less than a day. Either Terada’s memory had faded

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with time or in writing for a literary journal Terada consciously rearranged the sequence of events for the sake of storytelling (cf. Nagaoka & Terada’s letters in Appendix 4). Our interpretation of events is based on the opening paragraph of a letter dated May 31, 1917 that Terada wrote to Birkeland in English: I can see now quite well how unhappy you must have been in Egypt. I am inﬁnitely sorry for it. Now you are among us the scientiﬁc men who are brethren all over the world, are they not? You can be quite assured that we all esteem you as one of the distinguished members of the scientiﬁc world and very glad to have you staying near us. I do not believe that any persecution of the kind you imagine may continue to bother you. Here it is so peaceful that you perhaps will notice yourselves (sic) in the course of time. If you have still anything you may feel uneasy or nervous, please let us know straightforward.

A literal interpretation of The Death of Professor B would require that Birkeland forgot the events of May 31 and repeated his tale on June 14 but Terada did not think this worth noting in his dairy. Terada’s diary entry for June 15th relates that he, Nagaoka, Miura and T Ambassador Anker received an urgent call that Birkeland was in critical condition at his hotel, “We heard that he had taken last night about 11 grams of veronal, possibly with the intention of committing suicide.” Dr. Muira tried artiﬁcial respiration to revive Birkeland to no avail. In his short story Terada wrote: I heard from the room servant that the night before Prof. B had asked the servant to buy some sleeping medicine. When the servant brought the medicine, Prof. B asked him to buy some more. The servant replied that it would not be good for his health to take such a big amount, but Prof. B insisted that he could not sleep without the medicine. So the servant went out again to buy more medicine to satisfy Prof. B’s request.

The ofﬁcial cause of death, a heart attack, was not inaccurate. Taken in large quantities veronal acts to suppress the brain activity that controls breathing. To keep supplying his brain with oxygen his heart would have tried to pump faster and faster until it failed. Birkeland’s state of mind and whether he intended his own death can never be known with absolute certainty. External evidence such as his purchases in Japan and his continuing research suggest that his intention was to get much needed sleep, and his death was an accidental result of his clouded judgment. In addition to his new wardrobe, Birkeland had purchased several brass sculptures. There were also a number of books and a few manuscripts in the room. According to Nagaoka and Terada’s letter to Carl Størmer, a paper Birkeland was then working on lay nearby, “On the table in the corner was a stack of paper that looked like a draft for a treatise.” Ambassador Anker decided that until he heard from Dr. Tønnes Birkeland in Norway, Birkeland’s body should be stored at the Department of Anatomy, Imperial University of Tokyo and injected with embalming ﬂuid for preservation.

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Tønnes responded that Kristian’s body should be cremated and his ashes returned to Norway as soon as the war was over. Anker arranged for a Christian service to be held in the German Church. Since none of Birkeland’s family was present, Anker addressed the gathering. Dean Nagaoka also eulogized Birkeland saying, “What he achieved in 50 years of his life is as brilliant as the dazzling waves of the auroras, that exerted a mighty attraction on him.” Results of Birkeland’s work during his last years, which he showed to Terada and described to Krogness and Olaf Devik, are as important as his other books and papers. Personnel from the Norwegian Embassy packed Birkeland’s scientiﬁc documents for shipment to Norway on the Swedish steamship Peking P that set sail from Japan near the end of August 1917. A wireless communication was received from the vessel on September 2, as it approached Korea. It was never heard from again. In October the Peking P was added to Lloyd’s List of Missing Ships. Most of Birkeland’s belongings went with it to the bottom of the ocean. When the news of Birkeland’s death reached Norway, both the University and Norsk Hydro arranged special memorial services. Aftenposten carried a long article on June 16 that was reprinted in the international press. The ﬁrst paragraph reads: Professor Birkeland died on Friday, June 15, 1917 before he reached the age of 50. This is an irreplaceable loss for Norwegian science. He had a creative and constructive mind. He worked with the most complicated problems along the boundary between physics and mathematics. He was interested in secrets of the universe and as a surprise to everyone he found answers to questions researchers have worked on for centuries.

Sem Sæland wrote a brief biography in the same paper in which he listed Birkeland’s main areas of basic and applied research. Birkeland plumbed deeper into the problems of aurora, magnetic disturbances, electromagnetic forces, and the creation of the universe than any previous researcher. In addition, he discovered the Birkeland-Eyde method for producing fertilizer, a critical discovery of the last century. Appendix 2 lists nine different biographies written shortly after his death. After the war, Ambassador Anker’s wife carried Birkeland’s ashes back to Norway and the University of Kristiania. Birkeland was buried in the cemeVestre Gravlund in Kristiania on September 22, 1919. The University artery V ranged a formal ceremony with his family, colleagues, and friends in attendance as Birkeland’s ashes were interred. The Vice-Chancellor of the University of Kristiania and Professor Sem Saeland, then Vice-Chancellor of the Technical University in Trondheim, gave memorial speeches. For Norwegians Birkeland was a national hero. However, his death was overshadowed by the suspicion of suicide which for many years muted the praise that he deserved from the Norwegian nation.

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It was not until November 4, 1952, that the University of Oslo constructed a memorial above Birkeland’s grave. Professor Lars Vegard gave a commemorative speech in which he compared Kristian Birkeland to, “a neutron that starts a chain reaction in the world of spirits.” A plaque was mounted on which Olaf Devik summarized Birkeland’s work. The English translation is: He combined atmospheric nitrogen in his electromagnetic furnace. He investigated the nature of auroras, the Sun’s radiation and the Earth’s magnetic ﬁeld.

In retrospect, suicide seems an unlikely cause of death. Although Terada noted that Birkeland was in poor health, he had possessed sufﬁcient physical strength and mental acuity to critique Terada’s paper. Birkeland had overcome serious health problems in the past. Is it possible he considered his situation worse than previous illnesses? A mysterious telegram to his lawyer Johan Bredal suggested that he did. In the telegram to Johan Bredal, sent from Tokyo shortly before his death, Birkeland wrote in English, “Please remember Mrs. Wriedt’s committee.” On this basis speculation arose that Birkeland had become an active spiritualist during his last years. Bredal did not understand what Birkeland meant and was even unaware that he had left Egypt. If this telegram was indeed sent by Birkeland, it is surprising because Bredal knew very little English. In fact, Birkeland sent several telegrams during his journey from Egypt to Japan and after his arrival in Tokyo, but all the others were written in Norwegian. Mention of Mrs. Wriedt was also puzzling based on Birkeland’s previous experience. Around 1900, interest in spiritualism was growing in Norway, and many mediums were active. A few well-known scientists in England and America joined spiritualist societies, but most people were skeptical about the possibility of communicating with spirits of the dead. In August 1912, a s´e´ ance that lasted three evenings took place at a hotel in Kristiania led by a famous medium from the United States, “The Extraordinary Madame Wriedt”, as she called herself. Her specialty was called channeling, since she made contact with the spirits of the dead using a trumpet-like metal tube, nearly a meter high. Even though Madame Wriedt only spoke English, it was claimed the dead often spoke in foreign tongues. Bredal and the editor of a major newspaper in Norway had asked Birkeland to chair a scientiﬁc committee who would render an unbiased evaluation of Mrs. Wriedt’s abilities. The committee attended three gatherings and concluded that it was a fraud. Birkeland also published a personal report in the same newspaper (Tidens T Tegn, August 18, 1912). Excerpts from his article, translated into English, read:

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I have seen Mrs. Wriedt’s spirit in action. The audience fell silent as the lights were turned off and Mrs. Wriedt appeared wearing a phosphorescent dress. I sat next to her but was not allowed to touch her. She promised to speak loudly because of my bad hearing. She did a lot of talking and moving around for about 20 minutes. Then she placed the aluminium tube in the center of the ﬂoor and said that the spirits would send messages through the trumpet. She bade the spirits to enter it and shortly thereafter a loud bang was heard, the metal tube ﬂew into the air and landed in the lap of an elderly lady. Someone heard whispering sounds and other claimed they saw some old faces, with whom they could speak.

The strategic stage prop for her performance was the aluminum tube through which, she claimed, the spirits spoke. Birkeland wanted to look into it before the w seance, ´ but Mrs. Wriedt refused permission. After the s´eance, ´ he could smell explosive gas from the tube. Birkeland’s article concluded: We could easily re-enter the darkest of the Middle Ages if we were to give in to monsters such as Mrs. Wriedt. I place my scientiﬁc name and reputation as a guarantee that the medium, Mrs Wriedt, is a swindler. In principle, I am against burning witches, but a small ﬁre in honor of Mrs. Wriedt might not be out of place.

Jago (2001, p. 274) relates that when Bredal’s legal assistant told Olaf Devik about the telegram, they decided that Birkeland had anticipated his death and was prompting them to try to contact him beyond the grave. She quotes a May 1918 letter from Devik to Sir Oliver Lodge, a British physicist interested in paranormal phenomena. He requested that Lodge, “ask some of the best mediums to try to communicate with the professor.” Ever the rational scientist, Birkeland’s spirit refused to thrust Norway back into the Middle Ages and remained silent. We were unable to conﬁrm this story with letters from Olaf Devik’s archives. However, we have found a copy of a letter to Olaf Devik dated November 9, 1967 in which a legal assistant to Bredal, named Henning Bødtker, informed Devik for the ﬁrst time about the existence of the telegram. 9.5 MANY FRIENDS From what we have seen, Birkeland had a wide spectrum of friends and acquaintances. Some like Henri Poincar´e´ , Lord John W. S. Rayleigh, Elling Holst, Vilhelm Bjerknes, Henrik Mohn, Ole Andreas Krogness, Sophus Lie, Lars Vegard, Amund T. Helland, Richard Birkeland, and Sem Sæland came from academic backgrounds. Others like Roald Amundsen and Fridtjof Nansen were famous Arctic explorers. Birkeland was also acquainted with contemporary artists and musicians. To varying degrees, industrialists (Sam Eyde), international ﬁnanciers (Marcus Wallenberg) and political leaders (Gunnar Knudsen) recognized the genius of Kristian Birkeland. Birkeland lived most of his life in a male-dominated world from which he never sufﬁciently extricated himself

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to experience normal family life. This does not imply that in any way he was a misogynist. His friendships with Kaja Geelmuyden, the Danish scientist Hanna Adler, Ida Charlotte Hammer, Gerda Thomsen, and Hella Spandonides as well as his championing of Ellen Gleditsch’s academic career attest to this. His generosity toward Ida in their divorce settlement perhaps reﬂects Birkeland’s personal realization that he had failed to become the companion she had every right to expect in marriage. Throughout this biography we have mentioned a number of men and women who affected f Birkeland’s life. The following paragraphs provide brief biographical sketches of 11 close friends. Jules Henri Poincar´e (1854–1912), a giant of modern mathematics and physics, was born in Nancy, France, the son of a Professor of Medicine. He entered L’Ecole Polytechnique in 1873 and graduated two years later with a degree in mathematics. In 1879 he completed a doctorate in mathematics at the University of Paris under Charles Hermite. He was appointed Professor of Mathematics at the University of Paris in 1881 and Professor of Mathematical Physics and Probability at the Sorbonne in 1886. Thereafter, he held both positions until his death. During his closest interactions with Birkeland, Poincar´e was working on his famous three-volume Les M´ Methodes nouvelles de la mechanique ´ c´eleste ´ . In addition to his many contributions to mathematics and physics, Poincar´e was an astute student of the psychology of scientiﬁc learning. Unlike Birkeland, Poincar´e maintained a very strict schedule, dedicating four hours a day to research. He believed the subconscious mind continuously churned over problems. Therefore, he would never engage in research-related activities after 7 PM, lest they interfere with his sleep and thus his creativity. A clue to his life-long support for Birkeland’s work is found in his Mathematical Deﬁnitions in Mathematics (1904) in which he wrote, “It is by logic we prove, it is by intuition we invent.” In Birkeland he found both the intuitive imagination needed to grasp physical reality in new ways and the mathematical skills needed to prove or disprove the hypotheses of his intuition. Sem Sæland (1874–1939) was one of Birkeland’s most trusted and able assistants in his early years at the University, particularly during his polar expeditions. As well as a passion for research, they also shared similar political views and strongly opposed the Union with Sweden. After his political activism jeopardized his academic career, Sem spent a year teaching in Iceland before returning to ﬁnish his studies in mathematics and physics. During the Haldde expedition, Sem operated the Talvik mountain station, a critical and often lonely assignment. He was temperamentally well suited for the task, calm, experienced with instruments, and able to endure the isolation and harsh conditions. Sæland’s experience in Iceland later proved valuable during the 1902–1903

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expedition when Birkeland chose him as the leader of the Dyrafjord station. After Birkeland was bitten by the rabid dog in Archangel, Sæland was called upon to establish the Matotchkin Schar station on Novaya Zemlya before going to Iceland.

Figure 73. Sem Sæland (1874–1939). F

Throughout his academic career, Sæland collaborated with Birkeland. In 1909, he became a professor at the new Technical University in Trondheim and soon was named the ﬁrst Vice-Chancellor (1910–1914). From 1916 to 1918 Sæland was a Liberal party member of the Storting. He was appointed professor at the University of Kristiania in 1923 and from 1928 to 1936 was the Vice Chancellor (Figure 73). Olaf Devik (1886–1986) and his brother Karl were Birkeland’s most dedicated friends and assistants. Olaf began working part-time in the laboratory in1906; he and Karl became full-time assistants in 1910. Karl had a technical background and mainly worked in the terrella laboratory with Dietrichson. In Egypt, Karl became Birkeland’s close friend and conﬁdante. In Norway, Olaf was his favorite scientiﬁc assistant and served as his personal secretary. Birkeland called Olaf “his extended arm”. In 1915, Olaf became one of the directors of the Haldde Observatory, and he made signiﬁcant contributions to the development of reliable weather forecasting in Norway. In 1935, he was appointed to the highest civilian position at the Department of Education in the Government. Olaf and Sem Sæland worked tirelessly to make Birkeland’s research known to the general public in Norway (Figure 74).

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Figure 74. Olaf Devik (1886–1986). F

Although Professor Vilhelm Friman Koren Bjerknes (1862–1951) was ﬁve years older than Birkeland, they came to know each other very well. Bjerknes was a research assistant at the University of Kristiania while Birkeland studied there; both graduated in physics. In 1890, Bjerknes did postgraduate studies in Bonn, Germany under the guidance of Professor Heinrich Hertz where he performed comprehensive research on electric circuit resonances that were critical for developing radio communications. In 1895, Bjerknes became Professor of Applied Mechanics at the University of Stockholm; in 1907, he accepted a professorship in Geophysics at the University of Kristiania. Five years later he returned to Germany to direct the Leipzig Geophysical Institute. In 1917, Bjerknes moved back to Norway to head the Bergen Geophysical Institute. Finally, in 1926 he came home to the University of Kristiania where he remained until retirement in 1932. In 1904, Bjerknes developed a farsighted program for physical weather prediction based on the fundamental dynamic principles of physics. As a result, from 1905 to 1941 the Carnegie Foundation awarded him an annual stipend to support his research. His most important work, On the Dynamic of the Circular Vortex with Applications to the Atmosphere and to Atmospheric Vortex and Wave Motion (1921) established Bjerknes as a founder of modern meteorological forecasting. Professor Henrik Mohn (1835–1916) is regarded as the founder of Norwegian meteorology. He consistently supported Birkeland’s geophysical research. Mohn studied at the University of Kristiania, graduating in 1860 with a degree in astronomy. In 1866, Mohn was appointed Professor of Meteorology at the University of Kristiania and shortly thereafter became the ﬁrst director

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of the newly formed Norwegian Institute for Meteorology. Mohn then started to develop the methodological and organizational infrastructure needed for weather predictions, particularly the forecasting of big storms. In 1872, he published his ﬁrst important results in About Wind and Weather. Later he performed fundamental research on movements in the atmosphere, and with ´ Professor C. M. Guldberg published his main work, Etudes sur les mouvements de l’atmosph´ere (1880). Mohn was also interested in climate. His book A Climate Atlas of Norway (1906) describes his important climatological discoveries. He analyzed meteorological measurements of Birkeland and Nansen and strongly supported international cooperation. Professor Ole Andreas Krogness (1886–1934) graduated from the University of Kristiania in 1910 with a degree in physics. He began working with Birkeland in 1907 and became one of his dedicated assistants. Krogness followed Birkeland on several expeditions and contributed to the analysis of the magnetic recordings found in NAPE. He was responsible for the construction of the ﬁrst camera used to photograph auroral displays which was ready for systematic use in 1909. He became superintendent of the Haldde Observatory on July 1, 1912. Krogness was a cultured man, a descendant of the musical Lindemann family, and he set the tone for cultural life wherever he worked. Colleagues remember him with an affection seldom accorded to an individual. His main scientiﬁc contribution related to the analysis of polar elementary storms (Figure 75).

Figure 75. Professor Ole Andreas Krogness (1886–1934). F

Professor Lars Vegard (1880–1963) is today best remembered for his discovery of the weak spectral lines of the Balmer series in auroral emissions from hydrogen atoms. Vegard became one of Birkeland’s assistants in 1906. He conh tributed to the analysis of geomagnetic data included in Volume I of NAPE and occasionally substituted as a lecturer in Birkeland’s place. Birkeland helped him

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Figure 76. Professor Lars Vegard (1880–1963). F

obtain a scholarship to the University of Cambridge from 1908 to 1910 and fellowships for several study trips to Germany, Great Britain and The Netherlands. Vegard became an associate Professor of Physics in 1913. Cooperation between Birkeland and Vegard went very well until 1911. After that Vegard and Carl Størmer came to agree with British critics of Birkeland’s auroral theory, and Vegard, too, argued that the positive ions must have a dominating contribution in geophysical phenomena. In spite of their disagreement, Birkeland continued to support his study of the auroral spectra. However, they never published any joint papers. In 1918, Vegard succeeded Kristian Birkeland as Professor at the University of Kristiania (Figure 76). Kaja Geelmuyden (1865–1918) was a sister of Professor Hans Geelmuyden, director of the Astronomical Observatory at the University. Birkeland knew the whole Geelmuyden family, and was often invited to their home for dinner. Another sister, Marie, was the ﬁrst female to graduate in Mathematics from the University, and she later married Birkeland’s friend, Vilhelm Bjerknes. Birkeland was particularly close to Kaja. While some have suggested that they were lovers, in a letter to Tønnes Birkeland, Kaja recounted that she was really more like a substitute mother or a “confessor”. Birkeland often invited her to attend special social events with him, and she even accompanied him on some trips abroad. Several letters passed between them that shed light on his last months. Professor Amund T. Helland (1846–1918) was one of Birkeland’s closest friends from outside the physics community. He was a brilliant geologist who wrote an encyclopedia on The Land and People of Norway. By all accounts, he was quite eccentric and very controversial within the University. Helland was a

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committed socialist who wrote highly critical pieces in Morgenbladet, the most left-leaning newspaper of the time, attacking any public ﬁgure he felt deserved a drubbing. He then ignored his victims’ responses. The Storting appointed him a professor over the faculty’s objections. Although Helland was 21 years older than Birkeland, they usually voted together at faculty meetings. Helland was one of the few friends with whom Birkeland discussed personal problems and concerns. He also advised Birkeland on ﬁnancial investments and selecting good wines. Before Roald Amundsen (1872–1928) embarked on his famous expedition of 1903 aboard the Gjøa in search of the Northwest Passage, he sought Birkeland’s advice on the operation of magnetic instruments. One of his objectives was to determine the extent of the migration of the geomagnetic pole since its discovery by James Clark Ross in June 1831. In preparation, Amundsen spent time working at Birkeland’s K˚a˚ fjord station. The Gjøa expedition lasted for more than three years. Amundsen and his crew made magnetic measurements at King William’s Land in Gjøahavn for 700 days transporting their instruments on dog sleds. Unfortunately, Amundsen did not seek Birkeland’s help after the expedition, and his magnetic ﬁeld measurements were never analyzed. Professor Fridtjof Nansen (1861–1930) was famous as a polar explorer, oceanographer, statesman, and humanitarian. He was appointed Professor of Zoology at the University of Kristiania in 1896 and Professor of Oceanography in 1898. His oceanographic research won international recognition. An active nationalist, Nansen was deeply involved in politics and played a leading role in dissolving the Union with Sweden. He was assigned to keep the nations of central Europe informed about Norway’s political situation through newspaper articles and public lectures. Nansen was particularly effective in the United Kingdom and in 1906 became Norway’s ﬁrst ambassador in London. He personally played a central role in persuading the Danish prince Carl to become King H˚a˚ kon VII of Norway. At the conclusion of World War I, Nansen was active in the repatriation of prisoners of war. In 1920, he headed the Norwegian delegation to the League of Nations. His career culminated with the Nobel Peace Prize of 1922. 9.6 BIRKELAND’S WILL According to Norwegian law, Tønnes Birkeland, was his only brother’s heir. Tønnes contacted the lawyer Johan Bredal on June 17, 1917 and asked him to administer his brother’s estate. Tønnes had not seen Kristian’s will, and surprisingly, even Bredal did not have a copy. Shortly thereafter, they discovered

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that Birkeland had a safety box at the Bank of Norway in which he had left the will. The three main bequests were: 1. The interest from 60,000 kroner was put aside for his former wife Ida for as long as she lived. 2. The rest of the estate was divided equally between Tønnes and his children who would receive the money only after reaching the age of 21. When Ida died, the 60,000 kroner was divided in the same way. 3. All scientiﬁc instruments, textbooks, manuscripts, and published material were given to the Department of Physics, University of Kristiania. Because of wartime disruptions, Birkeland’s shares and properties were not carefully listed. Thus, the ﬁnal document could not be signed until January 2, 1921. After discussions with its new director general, Norsk Hydro put aside 60,000 kroner to cover Ida’s share. On December 20, 1917 Ida and Tønnes Birkeland agreed that they would ask nothing further of Norsk Hydro. Birkeland’s assistants were all compensated for their work. The value of Birkeland’s estate at the time of his death was equivalent to almost 20 million kroner today. Birkeland owned two farms, one of them ffairly large, many shares in different companies and mortgage bonds. Devik, Krogness, and Richard Birkeland were asked to examine all books, manuscripts, letters, and work-related documents to insure that no controversial documents, letters or instruments were given away. Literary books and Birkeland‘s wine collection were given to Tønnes. Valuable pieces of art were sold at auction. Ambassador Anker sent a long report from Tokyo, together with the 7,000 kroner Birkeland had with him when he died. He also promised to send all of Birkeland’s personal belongings to Norway as soon as the war ended. Unfortunately, Anker’s report has disappeared. Birkeland’s properties in Egypt presented particular difﬁculties for his lawyers. On the advice of Karl Devik they estimated its value as 60,000 kroner, but decided not to sell the Helwan villa until after the war. The lawyers also tried to contact Gerda Thomsen, who had promised to look after Birkeland’s properties in Egypt, but received no response. They concluded that the villa should be part of Tønnes’ inheritance, with an assigned value of 30,000 kroner. Tønnes then contacted Harold Knox-Shaw the director of the Khedivial Astronomical Observatory, offering him free use of the villa through the end of 1919, in gratitude for his assistance to Birkeland. He accepted the offer. In December 1919, Karl Devik returned to Egypt and sold V Villa Mea for 30,000 kroner. For their work in administering the will, Johan Bredal and Henning Bødtker received an honorarium of 8,000 kroner. In 1921, all of the money was deposited in the Porsgrunn r Saftybank, the bank used by Tønnes. What happened thereafter was a monetary disaster for

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Birkeland’s nephews and nieces. By the end of the 1920s, the ﬁnancial situation in Porsgrunn and throughout Norway was extremely bad. Everyone in Porsgrunn knew of Dr. Birkeland’s substantial inheritance from his famous brother. Town managers approached Tønnes to ask if he would lend them money at high interest. This he did. In 1929, Porsgrunn was the ﬁrst town in Norway to default on a loan, and all Birkeland’s money was lost. Shortly thereafter the Storting passed a new law making it illegal for a town to default on loans.

Part V: Birkeland’s Heritage

CHAPTER 10

FROM SMALL ACORNS

The history of scientiﬁc understanding is replete with controversies, personal prejudices, and animosities between schools of thought that hold conﬂicting views. Birkeland suggested that auroral lights are caused by electron currents that follow the Earth’s magnetic ﬁeld, a view that Chapman and his followers could not accept. Opposition persisted even after space-probe measurements conﬁrmed Birkeland’s theory. Today, plasma physicists believe that many significant cosmic phenomena result from streams of “Birkeland currents” including: 1. 2. 3. 4.

Auroral rays, arcs, and draperies Auroral electrojets Magnetospheric “Inverted-V” structures “Flux ropes” in the ionosphere of Venus.

Birkeland currents are probably also critical to the development of other phenomena for which we still lack in situ measurements, such as: 5. 6. 7. 8.

Solar prominences, spicules, and coronal streamers Cometary tails, likely observed in 1986 Interstellar media and clouds Plasma within galaxies and galactic jets.

Peratt r (1996) suggested that pinched Birkeland currents might be the mechanism responsible for initiating the gravitational collapse of matter in the plasma state. Although Birkeland’s auroral theory has gained almost universal acceptance, his cosmological views have been little discussed. In this area, his work suggests that electromagnetic forces are more important than previously thought for understanding encounters between galaxies. At the very beginning of this biography, we noted that Kristian Birkeland was a person of his time, as we all are. His life is noteworthy not only for the many accomplishments of his relatively brief scientiﬁc career but also for the continuing inﬂuence of his ideas almost a century later. Two distinct areas bear further attention: Birkeland’s profound inﬂuence on scientiﬁc education

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in Norway and on the development of modern space physics. This chapter addresses each in turn.

10.1 SCIENCE EDUCATION IN NORWAY Birkeland established the ﬁrst permanent observatory for geomagnetism and auroral research at Haldde in northern Norway. By 1915, the Haldde program was extended to include meteorology. Over the years, many graduate students collected data for their theses at Haldde or the Auroral Observatory at Tromsø. Both as an individual and as a member of various appointed committees, Birkeland argued that Norway needed a technical university dedicated to practical and applied education. Consequently, the Technical University in Trondheim ((Norges Tekniske Høyskole) opened in 1910. In 1916, Birkeland submitted a proposal to the Storting for the installation of four automated meteorological stations on the islands around northern Norway to improve the quality of weather predictions and thereby assist the ﬁshing industry. In addition to his pioneering work in the new ﬁeld of cosmic-geophysics research, Birkeland introduced a new approach to physics in the way he educated his assistants. By direct example he taught them to build on solid theoretical foundations, imaginative laboratory simulations, as well as simultaneous and coordinated ﬁeld measurements. Birkeland’s success is best appreciated by considering the inﬂuential positions in science education attained by his assistants: 1. Sem Sæland (1874–1939) was the ﬁrst Professor of Physics at the new Technical University in Trondheim in 1910 and shortly thereafter became T its Vice-Chancellor. In 1923, he was appointed as a Professor at the University of Kristiania and was Vice-Chancellor there from 1928 to 1936. 2. Richard Birkeland (1879–1928) became a Professor of Applied Mathematics ﬁrst at the Technical University in Trondheim, and later at the University of Kristiania. 3. Ole Krogness (1886–1934) and Olaf Devik (1886–1986) held leadership positions at the Haldde Observatory and later became Professors of Physics in Norway. 4. Lars Vegard (1880–1963) was appointed Associate Professor at the University of Kristiania in 1913 and upon Birkeland’s death, replaced him in 1918. 5. Carl Størmer (1874–1957) and Thoralf Skolem (1887–1963) both became Professors of Mathematics at the University of Kristiania. 6. Torstein Weriede (1882–1969), a theoretical physicist who also worked with Birkeland, was appointed Associate Professor of Physics at the University of Kristiania in 1919.

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7. Claus N. Riiber (1867–1936) was a member of Birkeland’s nitrogenfertilizer team from 1903 to 1906, and in 1911 was appointed Professor of Chemistry at the Technical University at Trondheim. This list does not include his many assistants who worked for only one year or less, or his many graduate students who later taught at the high-school level. Cosmic-geophysics, or space plasma physics we call it today, has been and remains the largest ﬁeld of scientiﬁc education and research in Norway. Every Norwegian student knows of Birkeland’s electromagnetic cannon and his terrella experiments. 10.2 INFLUENCE ON SOLAR-TERRESTRIAL RESEARCH Chapters 3–5 discuss Birkeland’s truly innovative conclusions about the physical sources of auroral displays and their connection to geomagnetic disturbances. The perception that auroral and geomagnetic activities were related dates back at least to observations by Halley, Celsius, and Hiorter in the 18th century. Hansteen’s research, almost a century later, shows that the auroralgeomagnetic problem had not simply been noted and forgotten. Birkeland suggested a radically new perspective on an old problem that eventually led to the comprehensive understanding achieved by the end of the 20th century. The following paragraphs examine Birkeland’s methodologies in an effort to determine how he was able to understand geophysical phenomena that could be fully explored only after the advent of satellite measurements. Here, we consider two speciﬁc areas, solar-terrestrial connections and ﬁeld-aligned currents that link the ionosphere to distant reaches of geospace. Birkeland’s earliest publications include the ﬁrst general solution of Maxwell’s equations, four vector equations that describe the relationships between electromagnetic ﬁelds and their source electric charges and currents. Maxwell’s equations are as basic for understanding electricity and magnetism as Newton’s laws are for describing planetary motions. To a large degree, Einstein’s theories of special and general relativity show how Maxwell’s equations and Newton’s laws apply under extreme conditions. When Birkeland was a student at the University of Kristiania in the late 1880s, Maxwell’s uniﬁcation of electricity and magnetism was so new that it had not yet entered the undergraduate curriculum. Gifted with a strong mathematical intuition, the young Birkeland reached conclusions that won the life-long respect of Henri Poincar´e´ , France’s leading mathematical physicist in the early 20th century. Birkeland demonstrated theoretical prowess that provided the basis for exploring implications of Maxwell’s synthesis in the laboratory and in the ﬁeld. Heinrich Hertz was among the ﬁrst to test Maxwell’s predictions that electromagnetic waves propagate across empty space. To begin his investigations,

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Birkeland wisely sought to replicate Hertz’ published experimental results at the University of Kristiania. These experimental accomplishments motivated him to visit Bonn in 1894. Birkeland understood that Maxwell’s equations had universal applicability and that their implications would be fully revealed experimentally. In the very best sense of the word, Birkeland was an opportunist. When something new or unexpected happened in his experiments, he quickly recognized the new element and its potential implications. His electromagnetic cannon and the nitrogen-ﬁxation process together with his other patents were serendipities that would have eluded a lesser scientist. Birkeland’s venture into auroral physics does not seem to have been part of a grand career design. Rather it appears to be a consequence of his laboratory study of cathode rays in magnetic ﬁelds where Birkeland found an analogy to the auroral problem. For all their ﬁscal naivet´e´ , Birkeland’s auroral expeditions of 1899–1900 and 1902–1903 were scientiﬁcally comprehensive. They established the approximate height of auroral emissions and the intensities of electrical currents responsible for the observed magnetic perturbations. By analogy with his laboratory simulations, he realized that auroral emissions must be produced by “cathode rays”. The magnetic perturbations measured on the ground required a very energetic source capable of generating millions of amperes of current in the upper atmosphere. Birkeland correctly concluded that only the Sun was sufﬁciently powerful. Laboratory experiments using the terrella as an anode conﬁrmed both hypotheses. Estimated current intensities followed from an application of Ampere’s Law and were not disputed. However, the current source was debated for more than 60 years. Strictly speaking, Birkeland’s laboratory demonstrations of the solarterrestrial system are better described as simulations than experiments, and as such, were brilliant successes. Cathode rays produced bands of light around the magnetic poles similar to what we now call the auroral oval. From a rhetorical point of view, the simulations allowed Birkeland to argue by analogy about the causes of auroral and geomagnetic disturbance phenomena. Herein lie the strength and vulnerability of Birkeland’s approach. Given the technology available near the beginning of the 20th century, he had few other options. In any analogy, the compared objects possess both similarities and dissimilarities. Lacking deﬁnitive experiments, proponents and adversaries emphasize similarities and dissimilarities, respectively. Birkeland’s opponents chose to ignore the laboratory results and at ﬁrst denied the possibility that the Sun inﬂuenced geomagnetic activity. By 1938, however, Chapman and Ferraro allowed that temporary eruptions from the Sun could alter the shape and volume of the Earth’s magnetic ﬁeld to drive magnetic storms.

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Based on simulations with the terrella as a cathode, Birkeland argued that both positively and negatively charged corpuscles were emitted from the Sun, but the negatively charged corpuscles were largely responsible for observed auroral emissions and disturbances in the magnetic ﬁeld. From observations during solar eclipses, Birkeland recognized the existence of a relatively strong solar magnetic ﬁeld and suggested that cathode rays must escape from the polar region then bend toward the equatorial plane. This can be interpreted as the ﬁrst science-based prediction of the solar wind. It is difﬁcult to ascertain how literally Birkeland regarded his “solar cathode” analogy. Our present understanding of plasma physics began with a series of experiments conducted by Irving Langmuir (1881–1957) in the 1920s, two decades after Birkeland’s terrella experiments. It is doubtful that Birkeland could have understood that the solar corona consists of ﬂuid-like plasma. The Sun’s gravitational force is unable to balance the outward plasma pressure and radial ﬂow. At some critical distance from the Sun that depends on the coronal temperature, outward ﬂowing plasma becomes supersonic. In 1959, two Russian Lunik satellites were the ﬁrst to record high ﬂuxes of positive ions during their voyage to the Moon. The Mariner II and Explorer X satellites discovered a steady stream of mostly hydrogen ions moving away from the Sun. This we now call the solar wind. Thus, Birkeland correctly predicted the presence of a solar wind, but considered the driving force to be electrostatic rather than magnetohydrodynamic. The terrella experiments suggested that energetic electrons from the Sun are the immediate cause of auroral emissions. The trajectories of incoming electrons indeed seem to follow closely those mathematically predicted by Størmer. However, solar wind electrons have low energies. They can only reach the auroral ionosphere directly from the solar wind along magnetic ﬁeld lines connected to the dayside cusps. The cusps are weak points in the Earth’s magnetic shield that are found near local noon. Typically, they map to about 78◦ magnetic latitude in the dayside ionosphere. The world’s premier locations for observing these dayside auroral features are the Norwegian stations at Longyearbyen and ˚ in the Svalbard archipelago and at the South Pole Station on AntarcNy Alesund tica (Sandholt et al., 2002). Most of the other electrons responsible for auroral emissions reach the ionosphere after having ﬁrst been stored and accelerated in a part of the Earth’s magnetosphere called the plasma sheet. Until Russian and American satellites discovered the plasma sheet in the early 1960s, its existence was not even theoretically predicted. It turns out that the plasma sheet is also the source of electromagnetic energy that drives geomagnetic substorms. The exact processes that lead to substorm initiation still remain a point of contentious debate, but Birkeland’s basic intuition was essentially correct. Solar electrons reaching the upper atmosphere create auroral emissions. Neither he nor anyone else of his or the following generation anticipated that auroral electrons are ﬁrst

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trapped and then accelerated in the Earth’s magnetosphere. Trajectories calculated by Størmer and simulated in the terrella laboratory most aptly simulate those high-energy cosmic rays of solar or galactic origin in the Earth’s magnetic ﬁeld. Magnetic ﬁeld measurements from the four stations of the 1902–1903 expedition, supplemented by data from low to mid latitude observatories, allowed Birkeland to infer the existence of two large current systems that ﬂowed at polar latitudes. Millions of amperes are needed to explain global magnetic disturbances. Birkeland argued that the responsible currents connect to distant space through magnetically ﬁeld-aligned currents. While the ultimate source of these currents must be the Sun, the exact mechanism was left undetermined. In 1960, a magnetometer on the Pioneer V satellite showed that the solar wind was magnetized. The intensity varies from a few nanotesla during magnetically quiet times to several tens of nanotesla during large disturbances. This interplanetary magnetic ﬁeld (IMF) is weak and is carried away from the Sun by the solar wind. This observation has critical consequences for understanding solar control of dynamics in the terrestrial magnetosphere and ionosphere. In 1961, the British scientist James Dungey (1923) noted that if the IMF has a southward component, it is possible to explain how the solar wind drives the high-latitude current system. At the equator on the dayside, the Earth’s magnetic ﬁeld is northward. Regions of opposite magnetic polarities in laboratory plasmas merge with each other. Dungey considered three types of magnetic ﬁelds. The ﬁrst is the IMF that is carried away from the Sun by the solar wind. The second includes “closed” magnetic ﬁeld lines with both feet anchored to the Earth. The third forms when the IMF and closed ﬁeld lines merge on the dayside boundary of the magnetosphere. Two “open” ﬁeld lines form, each with one foot on Earth and the other in the solar wind. The fast streaming solar wind exerts stresses on these ﬁeld lines causing them to stretch to form the northern and southern lobes of the Earth’s magnetotail. At a great distance (about 640,000 km) downstream, the oppositely directed magnetic ﬂuxes of the two lobes come together and reconnect. Newly reconnected magnetic ﬁeld lines are initially stretched. They then snap back toward the Earth carrying with them any attached ions and electrons to form the plasma sheet. The ionospheric footprints of the moving magnetic ﬁeld lines trace out patterns that mimic Birkeland’s current system. Chapman and his coworkers argued that an equivalent-current system required no ﬁeld-aligned currents. In assessing this debate, Fukushima (1989, 1994) realized that with only ground-based measurements, it is impossible to decide whether Birkeland’s ﬁeld-aligned currents were present or absent during homogeneous conditions in the ionosphere. Lacking in situ experimental information, the attention of space physicists turned to examining the implications of

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Birkeland’s ﬁeld-aligned current hypothesis. Before discussing measurements of the satellite era, it is useful to consider two theoretical analyses from the 1960s. Bostr¨m (1964, 1967) constructed two detailed mathematical models of auroral arcs and their associated three-dimensional currents. The ﬁrst model assumes that ﬁeld-aligned currents ﬂow into the ionosphere at one end of an auroral arc and out the other. The second model assumes that ﬁeld-aligned currents ﬂow in sheets into the ionosphere on the equatorward boundary of the arcs and out along its poleward boundary. The most important contributions of Bostrom’s ¨ models were predictions about how electric and magnetic ﬁelds should vary in the presence of ﬁeld-aligned current driven auroras. A decade later it became known that both of Bostr¨o¨ m’s models are realized in nature. The ﬁrst model anticipated what we call the “substorm current wedge” in which ﬁeld-aligned currents ﬂow into the ionosphere on the eastern ends of substorm arcs and out at their western ends. However, most auroral arcs have the sheet-like ﬁeld-aligned currents characteristics of Bostr¨o¨ m’s second model. V Vasyliunas (1968) considered a variant of the equivalent circuit model and from energy considerations demonstrated that it could not be sustained without ﬁeld-aligned currents. To understand Vasyliunas’ argument, it is ﬁrst necessary to reﬂect on the motions of charged particles in magnetized plasmas such as the ionosphere. Left to their own devices, electrons and ions simply rotate in circles around magnetic ﬁeld lines at a rate called the gyrofrequency. In the auroral ionosphere, the gyrofrequency of electrons is about 1 MHz, but for O+ the dominant ion species is only 50 Hz. If an electric ﬁeld is applied perpendicular to the magnetic ﬁeld, both ions and electrons execute cycloidal trajectories with guiding centers that move with the same velocity. With no differences between ion and electron drift motions, there would be neither electric currents nor magnetic perturbations. Ionospheric plasma is created and maintained in the upper regions of the Earth’s atmosphere by ultraviolet light from the Sun and/or by incoming auroral particles. The plasma density is at most 1% of the neutral density. Neutral atmospheric density increases exponentially with depth into the atmosphere. Collision rates between plasma and neutral constituents increase similarly. Relative to their gyrofrequencies ions undergo many more collisions than electrons. The net effect of collisions with neutrals is that ions mostly drift in the direction of the applied electric ﬁeld but electrons generally drift perpendicular to both the electric and magnetic ﬁelds. The different ion and electron drift velocities generate two electric currents. Currents in the direction of the electric ﬁeld are called Pedersen currents. Currents ﬂowing perpendicular to both ﬁelds are carried by drifting electrons and are called Hall currents. “Equivalent currents” are mostly Hall currents.

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The presence of Pedersen currents in the ionosphere has consequences for energy balance and provides a theoretical requirement for ﬁeld-aligned currents. Pedersen currents in magnetized plasmas arise because ions and/or electrons collide with atmospheric neutrals, giving net drifts along the direction of the driving electric ﬁeld. In these collisions, the plasma gives up kinetic energy to the random motion of neutrals. When a current ﬂows through a resistor, collisions between current carriers and the resistor material cause the temperature of the resistor to rise. This process is commonly referred to as Joule heating, named after the English physicist James Prescott Joule (1818–1889). Unless energy is continually fed into the ionospheric circuit, the currents will quickly dissipate due to Joule heating losses. A fundamental relationship governing electric circuits is Kirchoff’s law, named after German physicist Gustav Robert Kirchoff (1824–1887), which requires that all currents in a circuit be continuous. If the equivalent currents were purely of the Hall type, they indeed could ﬂow continuously in the ionosphere. The addition of Pedersen currents necessarily introduces discontinuities, apparently violating Kirchoff’s law. Only two options are available. First, the ionosphere cannot act as a steady-state circuit. Current would quickly dissipate, similar to a capacitor’s discharging through a resistor. Second, the ionospheric circuit is continually fed by magnetic ﬁeld-aligned currents that connect to “generator” regions in the magnetosphere and/or in the solar wind. Since magnetic disturbances can last for many hours, a steady-state circuit must form in which ﬁeld-aligned currents are necessary to conserve energy. V Vasyliunas (1970) considered the relationship between electric circuits in the ionosphere and magnetosphere and how they couple via ﬁeld-aligned currents. His approach simply considers the requirements of force balance and current continuity at both ends of magnetic ﬁeld lines. In the magnetosphere, ﬁeld-aligned currents ﬂow whenever gradients in the plasma pressure and the volumes of magnetic ﬂux tubes become misaligned. Electric ﬁelds in the magnetosphere are important to create high plasma pressures, but they do not appear explicitly in the equation that governs the strength of ﬁeld-aligned currents. In the ionosphere, Kirchoff’s law speciﬁes the electric potential distributions needed to maintain current continuity. Ionospheric potentials then map along magnetic ﬁeld lines to specify potential distributions in the magnetosphere. Birkeland’s ﬁeld-aligned currents control the interactions of the ionosphere and the magnetosphere within a self-consistent system. Vasyliunas’ basic insight lies at the heart of computer simulations of magnetospheric electrodynamics. Detection and identiﬁcation of magnetic perturbations caused by ﬁeldaligned currents appear in retrospect far more straightforward than they were in fact. Flying a magnetometer on a satellite in a high-inclination orbit was

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a ﬁrst and necessary step. In 1983, Dessler described the ﬁrst recognition of ﬁeld-aligned currents: In early 1966, more than half a century after Birkeland had put forth his experimental and theoretical evidence regarding the existence of ﬁeld-aligned currents, Zmuda, Martin and Heuring submitted to the JJournal of Geophysical Research a paper reporting the existence of “transverse magnetic disturbances” in the auroral zone as measured by a satellite-borne magnetometer. I was editor of the space physics portion of JGR at the time. I had been attuned to the possibility of the existence of ﬁeld-aligned currents from listening to Alfv´e´ n at several meetings, reading some of his papers, and perhaps more importantly, from talking with Carl-Gunne F¨a¨ lthammer whose arguments inﬂuenced me greatly. In addition Patel w P [1965, 1966] reported localized magnetic disturbances measured with the satellite Explorer 12. These too had been interpreted as hhydromagnetic waves. Although I was one of the early champions of the use of hydromagnetic theory to explain geomagnetic phenomena, it seemed clear that these localized, low-frequency magnetic disturbances did not ﬁt the concept of a propagating wave. The disturbances must be caused by ﬁeld-aligned currents.

Dessler then relates that he refereed the paper himself and suggested that the authors include ﬁeld-aligned currents as possible sources of the observed magnetic disturbances. When the authors declined his suggestion, Dessler and a graduate student wrote an article for the JJournal of Geophysical Research arguing that ﬁeld-aligned currents had ﬁnally been detected. Between 1966 and 1970, Zmuda and coworkers published at least four papers on transverse magnetic perturbations. It was only in a late 1970 paper by Armstrong and Zmuda that the group publicly embraced a ﬁeld-aligned current interpretation of their data. Why did they take so long? No evidence suggests that they were inﬂuenced one way or another by the long debate between the British and Scandinavian schools. Zmuda’s description of the 1963-38C satellite and their onboard magnetometer indicates how difﬁcult it was in the late 1960s to make the precise measurements needed to identify ﬁeld-aligned currents. At the time many satellites were stabilized with large bar magnets that aligned with the Earth’s magnetic ﬁeld, but also induced a torque that made the spacecraft precess in a cone of 6◦ . Their magnetometer could measure only one component of the Earth’s magnetic ﬁeld. In the auroral zone, the Earth’s magnetic ﬁeld is about 50,000 nT. Typical magnetic perturbations caused by ﬁeld-aligned currents are a few hundred nT, causing the Earth’s magnetic ﬁeld to tilt by a few tenths of 1◦ . The suggestion of Cummings and Dessler (1967) to attribute the cause of the observed magnetic perturbations to ﬁeld-aligned currents was both correct and useful. However, the caution exercised by Zmuda’s group was prudent and in the long run placed the existence of Birkeland currents on unassailable ground.

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Figure 77. A sketch of the conﬁguration of the Earth’s magnetosphere. The center blue point F is the Earth; red lines illustrate the Earth’s magnetic ﬁeld. The bow shock in front of the Earth and the plasma sheet are also shown. The interplanetary magnetic ﬁeld has a modulating effect within the magnetosphere.

Takesi Iijima of the University of Tokyo and Thomas Potemra of the Johns Hopkins University Applied Physics Laboratory used a three-axis vector magnetometer on the TRIAD satellite in a circular polar orbit at an altitude of 800 km to systematize Birkeland currents in the high-latitude ionosphere. They discovered a large-scale system of ﬁeld-aligned currents that is nearly co-terminal with the auroral oval. Along the high-latitude boundary of the auroral oval, sheets of current ﬂow into the ionosphere on the dawn side and out of the ionosphere on the dusk side. Near the equatorward, boundary of the oval ﬁeld-aligned currents of opposite polarities connect the ionosphere to the magnetosphere. The poleward and equatorward systems of ﬁeld-aligned currents are called Region 1 and Region 2 current, respectively. Near noon another sheet of ﬁeld-aligned current with the opposite polarity develops poleward of a Region 1 current. Its presence or absence on the morning or afternoon side of magnetic noon is controlled by the east-west component of the IMF. This current is directly tied to interplanetary space and arises in response to stresses exerted on the magnetosphere by the solar wind via open magnetic ﬁeld lines.

CHAPTER 11

IN MEMORIAM

11.1 KRISTIAN BIRKELAND RESEARCH FUND On October 1, 1917, several Norwegian government leaders, including the prime minister and the president of the Storting, most of the professors of the Science Faculties at Norway’s two universities, the President of the Academy, several industrial leaders, well-known authors and lawyers circulated a proposal to establish “The Professor Kr. Birkeland Fund for Geophysical Research”. The Birkeland Research Fund would be administered by the Norwegian Academy of Science and Letters. Interest on collected money would be used to stimulate geophysical research, especially in northern Norway. Even the Director of Norsk Hydro Sam Eyde and Professor Carl Størmer, with whom Birkeland had serious disagreements, signed the initiative, over the objections of two of Birkeland’s closest associates, Professors Amund Helland and Richard Birkeland. However, Sem Sæland, Olaf Devik, and Daniel Isaachsen, who had initiated the proposal, overruled their objections and let the signatures stand.

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Norwegian newspapers carried articles related to Birkeland’s work and the memorial fund. Contributions were accepted until December 13, 1917, Birkeland’s 50th birthday. The Devik brothers opened Birkeland’s terrella laboratory to the public for a full week, drawing many visitors. The demonstration of Birkeland’s “universe” also received much attention in newspapers. In their public invitation, the committee wrote that they preferred 10,000 small contributions to 10 large ones. Within a month donations reached 300,000 kroner, a sum equivalent to more than 10 million Norwegian kroner today (Figure 78).

11.2 BIRKELAND SYMPOSIUM In August 1967, the International Association of Geomagnetism and Aeronomy (IAGA) and the Norwegian Academy of Science and Letters cosponsored The Birkeland Symposium on Aurora and Magnetic Storms. The date was chosen to honor the 100th birthday of Norway’s greatest space scientist. Nearly 200 scientists attended the week-long program which also included an excursion to Norsk Hydro. Proceedings of the symposium, including all 70 presentations, were published by Centre National de la Reseherche Scientiﬁque in a special issue of Annales de Geophysique, Vol. V 24 (Ed. by Egeland and Holtet, 1968) (Figure 79).

11.3 BIRKELAND LECTURE SERIES The University of Oslo, in cooperation with the Norwegian Academy of Science and Letters and Norsk Hydro, inaugurated The Kristian Birkeland Lecture series in 1986. The objective of the lectures is to commemorate different aspects of Birkeland’s achievements in technology, applied physics, and basic research. The lectures also seek to disseminate Birkeland’s work and ideas more widely within the international scientiﬁc community (Figure 80). Kristian Birkeland Lectures have been given by: 1987: Professor Hannes Alfv´e´ n, the Royal Institute of Technology, Stockholm, Sweden. 1988: Professor Alexander J. Dessler, Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, Alabama, USA. 1989: Professor Naoshi Fukushima, Tokyo University, Japan and Doctor Thomas A. Potemra, The Johns Hopkins University, Laurel, Maryland, USA. 1990: Professor James Van Allen, University of Iowa, USA. 1991: Professor Syun-Ichi Akasofu, Director, Geophysical Institute, Fairbanks, Alaska, USA.

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Figure 78. A short excerpt from the letter proposing establishment of “The Professor F Kr. Birkeland Fund for Geophysical Research”.

1992: Professor W. Ian Axford, Director, Max-Planck Institut, Lindau, Germany/New Zealand. 1993: Director Takasi Oguti, Solar-Terrestrial Environment Laboratory, Nagoya, Japan. 1994: Professor Stanley W. H. Cowley, Imperial College, UK. 1996: Doctor Anthony L. Peratt, Los Alamos National Laboratory, USA. 1997: Symposium marking the tenth year since the start of the Kristian Birkeland Lectures was arranged in Oslo where ﬁve of the earlier lectures gave their presentations. ¨ Max-Planck Institute, Garching, 1998: Professor Gerhard Harendel, Germany. 1999: Birkeland Symposium at Tokyo University, Tokyo. Bust of Kr. Birkeland permanently installed in the University Museum. 2001: Professor David Southwood, Director at the European Space Centre Headquarters, Paris, France.

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Figure 79. Front page of the Proceedings. F

2002: Professor Alan F. Roux, Director CNSR, Centre d’´e´ tude des Environnements Terrestre et Plan´e´ taires, CNSR-Universit´e´ Versailles SaintQuentin, Velizy Paris. 2003: Professor Leo A. Zelgenyi, Director, Russian Space Research Institute, Moscow, Russia. 2004: Astronaut Catherine Coleman, Mission Specialist, NASA Johnson Space Center, Houston, Texas, USA.

Figure 80. From left in ﬁrst photo: Olaf Devik, Sven Terjesin (Director of Norsk Hydro), Hannes F Alfv´e´ n, S.-I. Akasofu. In center photo: M. Duysine, J.-M. Vreux, A. Monﬁls, M. Henrist, Th. Sæmundsson, R. Lust, ¨ P. Stauning, G. Lange-Hesse, I. B. Iversen. Right photo: participants in the lecture hall.

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Figure 81. Front page of the published Birkeland Lecture no. 8 given by Professor Stanley W. F H. Cowley, Imperial College, UK in 1994.

Figure 82. Front side of the Norwegian 200-kroner banknote honoring Birkeland and his auroral F discoveries.

11.4 THE NORWEGIAN 200 KRONER BANKNOTE Kristian Birkeland was the ﬁrst Norwegian physicist to be honored by the government on ofﬁcial currency. Since 1994, a picture of Birkeland has appeared on the 200-kroner banknotes. Today, 200 kroner is roughly equivalent to $30 US or 25 EU. The front side of the banknote portrays Birkeland against a stylized pattern of the aurora with a large snowﬂake to commemorate his interest in the relationship between meteorology and other high-latitude phenomena. Also represented are familiar stellar constellations of the northern polar sky. A sketch on the left side of the note shows his terrella experiment

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Figure 83. A collector’s envelope from 1999 marking the one hundredth anniversary of BirkeF land’s Auroral Observatory at Haldde. At the same time, new Norwegian stamps honoring Birkeland’s auroral work were issued.

with a magnetized sphere representing the Earth suspended in a box-shaped vacuum chamber. The auroral zones are clearly visible on the terrella. The back of the banknote bears a map of Northern Europe marked with the locations of Birkeland’s geophysical observatories. The magnetic pole is shown encircled with a ring, and the dayside auroral oval over Svalbard is clearly marked. The lower right corner has Birkeland’s original drawing of the ﬁeld-aligned (Birkeland) currents outside the atmosphere. A hidden image of the Earth’s magnetosphere is visible if the banknote is viewed under ultraviolet light. Both in 1966 and 1999, Birkeland was honored on Norwegian stamps. In addition, the one hundredth anniversary of the ﬁrst permanent auroral observatory at Haldde was commemorated in 1999 with special stamps (Figures 82–83).

APPENDIX 1

BIRKELAND’S SCIENTIFIC PUBLICATIONS

1886 Antallet af frie bevægelser i et leddet stangsystem, Tidsskrift for ˚ 4, s. 174–176. Mathematik (Kbh.), R. 5, Arg. 1887 En generalisation af Sylvester skjæve pantograf, Tidsskrift for ˚ 5, s. 17–18. Mathematik (Kbh.), R. 5, Arg. 1890 Ein Satz uber ¨ algebraische Curven, Naturwissenschaftliche Monatshefte fur f Mathematik und Physik, Jg. 1, s. 417–424. f¨ 1892 Electrische Schwingungen in Dr¨a¨ hten, directe Messungen der fortschreitenden Welle, Annalen der Physik und Chemie. N.F., Bd. 47, 583– 612. 1893 Ondes electriques ´ dans des ﬁls; la d´epression ´ de l’ondes qui se propage dans des conducteurs, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´e´ mie des Sciences, T. 116, 93–96. 1893 Sur les ondes electrique ´ dans des ﬁls la force electrique ´ dans le voisinage du conducteur, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´e´ mie des Sciences, T. 116, 499–502. 1893 Sur les ondes electriques ´ le long de ﬁls mince; calcul de d´epression, ´ Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 116, 625–628. 1893 Sur la r´e´ ﬂexion des ondes electriques ´ a´ l’extr´e´ mit´e d’un conducteur lineaire, ´ Comptes Rendus Hebdomadaires des S´eances ´ de l’Academie des Sciences, T. 116, 803–806. 1894 Sur la nature de la r´e´ ﬂexion des ondes electriques ´ ues au bout d’un ﬁl conducteur, Kr. Birkeland et Ed. Sarasin, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 117, 618–622. 1894 Sur l’aimantation produite par des courants hertziens, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 118, 130–134. 1894 Sur la r´e´ ﬂexion des ondes electriques ´ au bout d’un ﬁl conducteur qui se termine dans une plaque, Ed. Sarasin et Kr. Birkeland, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 118, 793–796.

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¨ 1894 Uber die Strahlung electromagnetischer Energie im Raume, Annalen der Physik und Chemie. N.F., Bd. 52, 357–380. ¨ die Reﬂexion und Resonanz der Hertz’schen electrischen 1894 Uber Schwingungen, Erkl¨a¨ rung der Hagenbech-Zehnder’schen Versuche, Annalen der Physik und Chemie, N.F., Bd. 52, 468–495. 1894 Om krafttransmission, særlig i et elektromagnetisk Felt, Tidsskrift for Physik og Chemi, 3. bind, 353–373. 1895 Solution g´e´ n´erale ´ des equations ´ de Maxwell pour un milieu absorbant homog`e` ne et isotrope, Comptes Rendus Hebdomadaires des S´eances ´ de l’Acad´e´ mie des Sciences, T. 12, 1046–1050. 1895 Sur la transmission de l’´e´ nergie, Archives des Sciences Physiques et Naturelles, 3eme ` p´eriode, ´ T. 33, 297–309. 1895 Solution on g´e´ n´erale ´ des equations ´ de Maxwell pour un milieu absorbant, homog`e` ne et isotrope, Archives des Sciences Physiques et Naturelles. 3eme ` p´eriode, ´ T. 34, Geneva, p. 5–56. 1895 Sur l’aimantation produite par des courants hertziens, Un di´e´ lectrique magn´e´ tique, Comptes Rendus Hebdomadaires des S´eances ´ de l’Acad´emie ´ des Sciences, T. 120, 1320–1324. 1896 Sur les Rayons Cathodiques sous l’action de forces magnetiques intenses, Archives des Sciences Physiques et Naturelles, 4`e` me p´eriode, ´ T. 1, Geneva, 497–512. 1896 Sur un spectre des rayons cathodiques, Comptes Rendus Hebdomadaires des S´e´ ances de l’Academie des sciences, T. 123, 492–495. 1896 Om kathodestraaler under paavirkning af stærke magnetiske kræfter, Elektroteknisk Tidsskrift, Kristiania, Vol. 9, 104–110. 1896 Cathode Rays under the inﬂuence of strong magnetic forces, Electrical Review, p. 968. ¨ 1896 Uber Katodestrahlen unter Einwirknung von intensiven magnetiscen Kraften, ¨ Zeischrift f¨ fur Elektrotechnik, Wien, Vol. XIV, 448–450 and 475– 482. 1896 Sur les Rayons Cathodiques sous l’action de forces magnetiques intenses, Archives des Sciences Physiques. Geneve, Vol. 4, 497–512. 1898 Om indsugning af katodestraaler mod en magnetisk pol, Archiv for Mathematik og Naturvidenskab, Bd. 20, no. 15. (28 pages). 1898 Sur le ph´e´ nom`ene ` de succion de Rayons Cathodiques par un pole magn´e´ tique, Archives de Scieces Physiques et Naturelles, 4`eme ` p´eriode, ´ T. 6, Geneva, 205–228.

BIRKELAND’S SCIENTIFIC PUBLICATIONS

183

1898 Sur le spectre des rayons cathodiques II, Comptes Rendus Hebdomadaires des S´e´ ances de l’Academie des Sciences, T. 126, 228–231. 1898 Sur une analogie d’action entre les rayons lumineux et les lignes de force magn´e´ tiques. Comptes Rendus Hebdomadaires des S´eances ´ de l’Acad´e´ mie des Sciences, T. 126, 586–589. 1899 Recherches sur les taches du soleil et leur origine, Videnskabselskabets skrifter. I, Mat.-naturv. klasse, 1899, no. 1. (175 pages). ¨ 1899 Uber die Strahlung electromagnetischer Energie, Wied. Ann., Leipzig. 1900 Sur la constitution physique du soleil, Rapport present au Congr`es International de Physique, R´e´ uni a` Paris en 1900. (17 pages). 1901 Courants electriques ´ dans l’athmosph`ere ` polaire et aurores bor´eales ´ (Communication sur les r´e´ sultats obtenus par l’exp´edition ´ Norv´egienne ´ de 1899–1900 pour l’´e´ tude des aurores bor´eales), ´ Archives des Sciences Physiques et Naturelles, 4`e` me p´eriode, ´ T. 12, Geneva, p. 480–488. 1901 Resultats ´ des recherches magn´ethiques ´ faites par l’expedition Norvegienne ´ de 1899–1900. Pour l’´etude ´ des aurores bor´eales, ´ Archives des Sciences Physiques et Naturelles. 4`e` me p´eriode, ´ T. 12, Geneva, 565–586. 1901 Exp´e´ dition Norv´egienne ´ de 1899–1900 pour l’etude des auroras bor´e´ ales: Resultats ´ des recherches magn´ethiques, ´ Videnskabsselskabets skrifter I, Mat.-naturv. klasse, Kristiania, no. 1 (180 pages). 1901 Les taches du Soleil et les plan`e` tes, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 133, p. 726–729. 1902 On a new electric current breaker, Videnskabsselskabets skrifter, Mat.naturv. klasse, Kristiania, no. 11. (11pages) 1902 The proposed magnetic researches at the Norwegian Polar stations 1902–1903, Terrestrial Magnetism and Atmospheric Electricity, Vol. 7, 81–82. 1903 Concerning observations of terrestrial magnetism and clouds carried out at the Norwegian stations during the years 1902–1903, Terrestrial Magnetism and Atmospheric Electricity, Vol. 8, 74–75. 1906 On the oxidation of atmospheric nitrogen in electric arcs; To the Faraday Society, July 2, 1906, Transactions of the Faraday Society, Vol. 2. 1906 On the oxidation of atmospheric nitrogen in electric arcs, Nature, No. 1506, Vol. 58 (22 pages). ¨ 1907 Uber die Oxydation des atmosph¨a¨ rischen Stickstoffs im electrischen Lichtbogen, Nach einem in der Faraday Society gehaltenen Vortrage, Jahrbuch der Radioaktivitat ¨ und Electronik, Bd. 3, 264–290.

184

APPENDIX 1

1908 The Norwegian Aurora Polaris Expedition 1902–1903. Vol. 1, On the Cause of Magnetic Storms and the Origin of Terrestrial Magnetism, Sect. 1. Kristiania, Aschehoug; (Lpz.: Barth London, New York: Longmans; Paris. Klincksieck.) 1–316. 1908 Sur la cause des orages magn´e´ tiques, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 147, 539–543. 1908 Les orages magn´e´ tiques polarires et les auroras bor´eales, ´ Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 148, 30–33. 1909 Courants telluriques d’induction dans les r´e´ gions polaires, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 148, 56–59. 1909 Sur les orages magn´e´ tiques polaires en 1882–1883. Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ de Sciences, T. 148, 1006–1009. 1910 Transit of Halley’s comet across Venus and the Earth in May 1910, Nature, Vol. 83, 217–218. 1910 Sur le d´e´ viabilit´e magn´e´ tique des rayons corpusculaires proventant du Soleil, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 150, 246–248. 1911 Sur la lumi`e` re zodiacale, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 152, p. 345–348. 1911 Les Anneaux de Saturne sont-ils dus a` une radiation e´ lectrique de la pan`e` te? Comptes Rendus Hebdomadaires des S´eances ´ de l’Acad´emie ´ des Sciences, T. 153, 375–377. 1911 The simultaneity of certain abruptly-beginning magnetic disturbances, Lecture at Congress International de Physique, Paris, Nature, Vol. 87, 483–484. 1911 Le Soleil et ses taches, Comptes Rendus Hebdomadaires des S´eances de l’Acad´e´ mie des sciences, T. 153, 456–459. 1911 Sur la constitution e´ lectrique du Soleil, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 153, 513–516. 1911 Orages magn´e´ tiques et aurores polaires, Archives de Sciences Physiques et Naturelles, 4`e` me p´eriode, ´ T. 32, Geneva, 97–116. 1912 Mouvement d’une particule e´ lectris´ee ´ dans un champ magnetiques, Archives des Sciences Physiques et Naturelles. 4`e` me p´eriode, ´ Geneva, T. 33, 32–50.

BIRKELAND’S SCIENTIFIC PUBLICATIONS

185

1912 Mouvement d’une particule e´ lectrisee ´ dans un champ magn´etique ´ II, Archives des Sciences Physiques et Naturelles. 4`e` me p´eriode, ´ T. 33, Geneva, 151–175. 1912 Sur l’origine de plan`e` tes et de leurs satellites, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 155, 892–895. 1912 Sur la source de l’´e´ lectricit´e des e´ toiles, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 155, 1467– 1470. 1913 The Norwegian Aurora Polaris Expedition 1902–1903, Vol. 1, On the cause of magnetic storms and the origin of terrestrial magnetism, Sec. 2, Aschehoug; Kristiania, 319–801. 1913 Sur la conservation et l’origine du magn´e´ tisme Terrestre, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 157, 275–277. 1913 Oscillations hertziennes produites par des d´e´ charges intermittentes partant des teches isol´e´ es d’une cathode dans un tube de Crookes, Comptes Rendus Hebdomadaires des S´e´ ances de l’Academie des Sciences, T. 156, 879–881. 1913 Sur le magn´e´ tisme g´en´ ´ eral ´ du Soleil, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´emie ´ des Sciences, T. 157, 104–106. 1913 Remarques sur les essais faits par Halepour determiner ´ le magn´etisme ´ general du Soleil, Comptes Rendus Hebdomadaires des S´e´ ances de l’Academie des Sciences, T. 157, 394–395. 1913 Sur la conservation et l’origine du magnitisme terrestre, Comptes Rendus Hebdomadaires des S´e´ ances de l’Academie des Sciences, T. 157, 275–277. 1913 De l’origine des mondes, Archives de Sciences Physiques et Naturelles, 4eme ` p´eriode, ´ T. 35, Geneva, 529–564. 1913 La formation des nuages du niveau sup´e´ rieur: Revue g´en´ ´ eral ´ des sciences pures et appliqu´e´ es, Avec une introduction de J. Loisel, 24e ann´ee, no. 15, 576–581. 1913 Das Werden der Wellen, Naturwissenschaftliche Umschau der Chemiker-Zeitung, Jg. 2, 17–19. Nach einem Vortrage vor der Videnskabsakademiet i Kristiania am 31. Januar 1913. 1913 Die Wolkenbildung in h¨o¨ hern Schichten, mit Einleitung von J. Loisel, Revue G´e´ n´erale ´ des Scinceses.

186

APPENDIX 1

1914 On a possible method of photographically registering the intensity of the ultraviolet light from the sun and stars—preliminary note, The Cairo scientiﬁc journal, Vol. 8, no. 99, 287–194. 1914 Calcul des lignes d’intensit´e´ s egales ´ dans la lumi`ere ` zodiacal, Kr. Birkeland et Th. Skolem, Comptes Rendus Hebdomadaires des S´e´ ances de l’Acad´e´ mie des Sciences, T. 159, 495–497. 1914 Calcul des lignes d’intensit´e´ s egales ´ dans llumi`ere ` zodiacale, en supposant que celle-ci provient de la lumi`e` re diffus´e par une n´e´ bleuse d’´e´ lectrons ou de la mati`ere ` radiants d’origine solaire, Kr. Birkeland et Th. Skolem, Comptes Rendus Hebdomadaires des S´e´ ances de l’Academie des Sciences, T. 159, 464–466. 1914 Sur la lumiere ` zodiacal, Comptes Rendus Hebdomadaires des S´eances de l’Academie des Sciences, T. 159, 229–234. 1915 On a possible crucial test of the theories of auroral curtains and polar magnetic storms, Videnskaps-selskapets skrifter. I, Mat.-naturv. Klasse, Kristiania, no. 6. (6 pages). 1915 Une m´e´ thode enum ´ erative ´ de la g´eometrie. ´ Videnskapsselskapets skrifter, I, Mat.-naturv. klasse, Kristiania, no. 12 (61 pages). 1916 Les rayons corpusculaires du soleil qui p´e´ netrent ` dans l’athmosph`ere terrestre sont-ils n´e´ gatifs ou positifs? Archives des Sciences Physiques et Naturelles, 4eme ` p´eriode, ´ T. 41, Geneva, 22–37. 1916 Les rayons corpusculaires du soleil qui p´e´ netrent ` dans l’athmosph`ere terrestre sont-ils n´e´ gatifs ou positifs? Archives des Sciences Physiques et Naturelles, 4eme ` p´eriode, ´ T. 41, Geneva, 108–124. 1916 Are the solar corpuscle rays that penetrate into the earth’s atmosphere negative or positive rays? Videnskapsselskapets skrifter. I, Mat.-naturv. klasse, Kristiania, no. 1 (27 pages). 1917 Simultaneous observations of the zodiacal light from stations of nearly equal longitude in North and South Africa, The Cairo Scientiﬁc Journal, Vol. 9, no. 100 (Jan/March) (18 pages). V POPULAR SCIENCE CONTRIBUTIONS 1894 Om krafttransmission, særlig i et elektromagnetisk Felt, Lecture in Polyteknisk Forening, Printed in Tidsskrift for Physik og Chemi, 3. bind, no. 12, 353–373. 1896 Om hurtigt vexlende strømmes magnetiserende virkninger. Elektroteknisk Tidsskrift, Aarg. 9, p. 3–5.

BIRKELAND’S SCIENTIFIC PUBLICATIONS

187

1896 De Røntgen-ske Straaler, Morgenbladet; 25 March. 1898 Et bud fra solen, Verdens Gang; 16 September. 1898 Om indsugning af katodestraaler med en magnetisk pol, Archiv for Mathematik og Naturvidenskab, Bd. 20, no. 15. (28 pages). 1900 Underlige Tegn i Sol og Stjerner, Aftenposten; 13 January. 1900 Nordlysexpeditionen, Elektroteknisk Tidsskrift, Aarg. 13, No. 3, 1–198. 1905 Norsk salpeterindustri p˚a grundlag af Birkeland–Eyde’s elektrokemiske proces, Kr. Birkeland and S. Eyde, Norsk Tidsskrift for Haandverk og Industri, 1910 Magnetiske storme og nordlys, Eletroteknisk Tidsskrift, Aarg. 23, s. 235–245, also published in T Teknisk Ugeblad, p. 604–607. 1913 Om verdnernes tilblivelse, Contributions in Aftenposten, 1 February; also published in Festskrift til Aars og Voss’ skoles femtiaars jubilæum. s. 227–246; Elektroteknisk Tidsskrift, Aarg. 26, p. 59–63; and by the Norwegian Academy of Science and Letters, 31 January.

APPENDIX 2

ARCHIVES AND UNPUBLISHED SOURCES

The following archives have proven very helpful in writing this biography, especially the ﬁrst three. These and Birkeland’s publications have been our primary sources.

OLAF DEVIK’S PERSONAL ARCHIVE Olaf Devik gathered and annotated most of Birkeland’s published scientiﬁc papers, original letters, as well as documents belonging to Dr. Tønnes Birkeland, donated by his grandson Gunnar Birkeland. The archived documents mostly relate to the Haldde Observatory, Nobel Prize nominations, the Birkeland F Festschrift , his will and divorce settlement. Birkeland’s correspondence with Sem Sæland, Carl Størmer, Amund Helland, Kaja Geelmuyden, and Richard Birkeland is also available along with the original letter of January 1918 from Gerda Thomsen (Dr. Eriksen’s wife) in Egypt to Karl Devik. A signiﬁcant number of the documents concern Birkeland’s ﬁnancial dealings, conﬂicts with Sam Eyde and his relationship with Norsk Hydro. It also contains rough drafts of letters, manuscripts, lecture notes, photographs, excerpts from magazine articles and mail sent from Japan shortly before Birkeland’s death.

THE BIRKELAND–EYDE INDUSTRIAL MUSEUM AT NOTODDEN This archive mainly documents early testing of the Birkeland–Eyde process, as well as the planning, building, and operating of the ﬁrst factory at Notodden. It contains telegraphic communications between Birkeland and Eyde. Some written material from Karl Devik is also preserved here, e.g. a letter to his father conceding that Eyde and Størmer acted fairly in disputes with Birkeland. – October 1901 to 1903: Correspondence on the electromagnetic cannon and electric switches. – July 11, 1903: Birkeland’s letters to Lady Sander offering to work on the electromagnetic cannon in England and to Monsieur le President de la Commission des Inventions, Paris (Figure 52).

190

APPENDIX 2

– 1903: Eyde’s letters to Birkeland regarding the production goal of 400 kg/kW-year. – October 21, 1903: Letter from Eyde saying that more funds would not be forthcoming. – September 26, 1903: Birkeland’s letter to Storting requesting 10,000 kroner to analyze 1902–1903 polar expedition data. – 1905: Birkeland’s description of tests at Notodden. – May 2, 1905: Manuscript of Birkeland’s speech at the opening of Notodden Factory. – 1905: French positive impression with Birkeland process for fertilizer production. – April 7 and 12, 1906: Birkeland’s letters to Marcus Wallenberg. – April 18, 1906: Wallenberg’s response. – May 18, 1906: Birkeland’s agreement with Wallenberg to become the Adviser Director of Norsk Hydro and to receive an annual stipend for life. (Copies at the other archives.) – July 10, 1907: Rector Brøgger’s letter granting Birkeland permission to place an antenna on the roof of Domus Media at his own expense. – August 15, 1906: Birkeland’s letter on consultative directorship of Kvelstoffkompaniet. – 1908–1910: Documents about Otto Schonherr’s ¨ method for nitrogen ﬁxation. – July 1912: Protocols increasing Birkeland’s stipend from 10,000 kroner in 1910 to 12,000 in 1912. – December 5, 1939: Copies of letters from R. Sohlman of The Nobel Institute, regarding the Nobel Prize in Chemistry for Birkeland and Eyde. NORWEGIAN TECHNICAL MUSEUM IN OSLO This archive contains many documents concerning Birkeland’s work with X-rays, electric discharges and the terrella chambers. It also contains interesting documents about the establishment of Norsk Hydro. – February 17, 1903: Eyde–Birkeland agree to pursue Birkeland’s concepts and methods. – June 5, 1903: Birkeland’s ﬁrst company formed. – December 11, 1905: Copy of 75,000 kroner check from Enskilda Banken in Stockholm. – June 7, 1910: copy of 60,000 kroner check from Enskilda Banken in Stockholm.

ARCHIVES AND UNPUBLISHED SOURCES

191

– June 7, 1910: Birkeland’s letter of dismay with KvaelstoffkompanietBASF agreement. THE NATIONAL LIBRARY ARCHIVE – December 30, 1890: Letter to Vilhelm Bjerknes regarding Hertz radio experiments. – February 15, 1983: Letter to Vilhelm Bjerknes concerning his illness in Paris. – December 17, 1893: Letter to Vilhelm Bjerknes on “teaching the Swedish bear to drink.” – February 2, 1894: Letter to Elling Holst regarding his ﬁrst meeting with Heinrich Hertz. – Christmas, 1900: Letters to Elling Holst from Haldde on scenery and budgetary troubles. – 1903–1905: Documents related to establishment of Norsk Hydro. Copies of these documents are at several archives. – 1909–1913: Documents related to Birkeland’s involvement in iron and bismuth mines. NORSK HYDRO ARCHIVE This collection provides an excellent source on Norsk Hydro’s foundation and history, emphasizing technological details. – 1902–1909: Documents on patents and history of processes related to plasma furnaces. – December 11, 1903: Establishment of Kvælstoffkompaniet. – January 2, 1904: Establishment of Elektrokemisk. – May 6 and Oct. 5, 1903: Letter from Eyde to Birkeland regarding new employees. – May 18, 1906: Letter from Wallenberg to Birkeland about Technical Director position. – 1912: All of Birkeland’s patents purchased by Kvælstoffkompaniet. SAM EYDE ARCHIVE In contrast to Birkeland, Eyde took great care of important documents, letters, and unpublished sources. Background material for his 1939 autobiography Mitt liv og mitt livsverk is found here. However, some controversial documents are missing.

192

APPENDIX 2

– 1903–1905: Several letter and telegram exchanges between Eyde and Birkeland. – August 12, 1904: Letter from Eyde to complain about his name not on patents and to demand equal representation. – Fall, 1909: Birkeland appointment to head oversight committee in competition with BASF. NORWEGIAN STORTING ARCHIVES –Y Years 1901–1903, 1911–1917 contain interesting assessments of Birkeland’s work. The review of the Haldde 1899–1900 expedition (p. 1024– 1018) is very critical of Birkeland’s bookkeeping. UNIVERSITY OF OSLO, CENTRAL ADMINISTRATION Contains many of Birkeland’s letters concerning leaves of absence, new ofﬁces, and laboratories, the employment of assistants as well some references to his publications. STOCKHOLM ENSKILDA BANKEN ARCHIVES – 1905–1915: Birkeland’s correspondence with Marcus and Knut W Wallenberg. NORWEGIAN ACADEMY OF SCIENCE AND LETTERS ARCHIVE The annual reports of 1896–1917 contain information about Birkeland’s activities and lectures to the Academy. Birkeland was elected a member on March 23, 1896. PRINTED SOURCES FROM NORWEGIAN NEWSPAPERS AND JOURNALS Aftenposten: – January 13, 1900: Underlige Tegn I Sol og Stjerner. – Summer—Fall, 1902: Several articles regarding the auroral expedition. – March 6–7, 1903: Professor Birkeland and den Elektromagnetiske Kanon. – February 1, 1913: Om Verdnernes Tiblivelse. – March, 1915: Stormvarsler. Automatiske stasjoner. – June 28–29, 1915: Den Birkeland–Eydeske Opﬁndelse. – June 24, 1916: Den I de Polske land herskende Nød.

ARCHIVES AND UNPUBLISHED SOURCES

193

– June 17–18, 1917: Several articles about Birkeland’s death. – May 15, 1920: Birkeland’s undersøkelser I Egypt. Verdens r Gang: – September 6, 1898: Et bud fra solen. (Messenger from the Sun.) – October 19, 1898: P Portrait of Professor Kr. Birkeland. Morgenbladet: – November 10, 1894: Article on solution of Maxwell’s equations. – March 25, 1896: De Røntgen‘ske straaler. (About X-rays.) – April 15, 1900: Sem Sæland article about the Haldde expedition. – December 6, 1905: Birkeland and Eyde describe the Birkeland-Eyde method. – October 7, 1917: Foran Birkelands sol. Og bak verdensrummetskulisser Tidens Tegn: T This is also one of the biggest newspapers in Kristiania. – August 18, 1912: Den spiritistiske Humbug. Birkeland article about Mrs. Wreidt’s s´eance. Teknisk Ukeblad: T – December 7, 1905: No. 49, p: Norsk salpeterindustri p˚a grunnlag af Birkeland–Eydes elektrokemiske proces (Norwegian saltpeter and the basis of the Birkeland–Eyde electro-chemical process) No. 49, p. 497–514 and No. 50, p. 525–526. – 1910 p. 604–607: Magnetiske storme og nordlys (Magnetic Storms and Northern Lights) – page 604 to 610. Also an article in 1911 on the same subject. – 1917 No. 26: Professor Kr. Birkeland. Allers Familie-Journal: – June, 1900: Nordlysekspedisjonen. – October 14, 1906 (No. 41). Professor Kr. Birkeland, a detailed portrait. Elektroteknisk Tidsskrift: – October 17, 1910: Om Magnetyiske stormer og Nordlys. V Vol. 23. p. 235– 245. – February 1, 1913: Om Verdnernes Tiblivelse. – 1895–1917: References to Birkeland’s work and activities in every year.

194

APPENDIX 2 BIOGRAPHIES

– Devik, Olaf and Krogness, Ole A.: Professor Kr. Birkeland, Naturen, July 24, 1917. – Editor: Professor Kr. Birkeland, Elektroteknisk Tidsskrift, July 29, 1917. – Eyde, Sam, Professor Kr. Birkeland, Bergverksnyt, 13, pp. 97–98, 1917. – Sæland, Sem, Professor Kristian Birkeland, In Memoriam, Aftenposten, June 24, 1917. – Sæland, Sem, Professor Birkeland, T Teknisk Ukeblad, 32, pp. 33–42, 1919. – Sæland, Sem, Professor Kristian Birkeland, Fysisk Tidsskrift, Vol. V XVI, pp. 34–53, 1918. – Vegard, Lars, Professor Kr. Birkeland, T Teknisk Ukeblad, 26, pp. 300–303, June 1917. – Vegard, Lars, Professor Kristian Birkeland, pp. 407–415, 1917. – Almost all Norwegian newspapers carried Birkeland obituaries.

APPENDIX 3

PATENTS A

Birkeland held 60 Norwegian patents, including 10 with Sam Eyde and 5 with Olaf Devik. In the following tables, patents are listed topically in the ﬁrst line of each table; columns list information date, patent number, and a short title along with the name(s) of patent holder(s).

Date

Patent Number Short Title

Electromagnetic Cannon Sep 16, 1901 11,201 Dec 11, 1901 11,342 Apr 22, 1902 Oct 24, 1901

11,228 11,445

Mar 12, 1903 13,035

Apr 23, 1903

13,052

New method to ﬁre projectiles using electromagnetic forces Projectiles for electromagnetic cannons The electromagnetic cannon A method to avoid electric arcs with current-braking switches Rapid high-energy electric generation applied to g electromagnetic cannons Electromagnetic cannon systems

Nitrogen Fixation, Plasma Furnace and Absorption System Mar 20, 1903 12,961 New approach to produce electric discharges with maximum surfaces to decompose atmospheric gasses in the atmosphere g May 26, 1903 14,350 Approach and instruments for automatic current switching independent on voltages, and applications in different technology Jun 16, 1903 13,244 New instruments for use in patent 12,961 with suggested methods

Patent Holder(s)

Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland

Kr. Birkeland Kr. Birkeland

Kr. Birkeland

Kr. Birkeland

196

APPENDIX 3

Date

Patent Number Short Title

Patent Holder(s)

Jun 16, 1903

13,280

Kr. Birkeland

Aug 26, 1903 13,240

Sep 14, 1903

12,989

Oct 28, 1903

13,753

Feb 11, 1904

13,705

Feb 02, 1904

13,279

Mar 29, 1904 13,738 Mar 30, 1904 15,052 Mar 30, 1904 13,281 Jan 12, 1905

14,229

Apr 01, 1905 16,294 Jun 10, 1905

17,429

Oct 23, 1905

15,706

Jan 31, 1906

15,896

Feb 16, 1906

15,898

Approach to chemical binding or splitting of gasses by electric discharges from large arcs New approach to reduction or oxidation of solid matter in o electric heated furnace New approach for instruments for use in patent 12,961 with suggested methods Furnace to produce chemical, binding reactions in gasses. New methods to accelerate electric reactions in gasses by large-arc discharges New instruments for producing electric reactions in gasses by electric discharges New approach to Birkeland electric furnace system Regarding gas circulation in Electric ﬂame furnaces The mounting of the electrodes in electric ﬂame furnaces The use of big magnetic ﬁelds in furnaces of system Birkeland Electric ﬂame furnace to treat g gasses Electrode mounting and use of magnetic ﬁelds in electric ﬂame furnace of Birkeland system for chemical binding or dissociation of gasses New electrodes in the electric furnace for treating gasses New mounting of electric ﬂame furnaces New approach for construction of electric ﬂame furnaces

Kr. Birkeland and Sam Eyde Kr. Birkeland

Kr. Birkeland Kr. Birkeland

Kr. Birkeland

Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland and Sam Eyde Kr. Birkeland

Kr. Birkeland and Sam Eyde Kr. Birkeland Kr. Birkeland

PATENTS A

197

Date

Patent Number Short Title

Patent Holder(s)

Feb 16, 1907

17,400

Kr. Birkeland

Mar 11, 1907 17,834 Mar 23, 1907 18,236 Sep 27, 1907

18,854

Oct 31, 1908

20,486

Apr 21, 1909 20,670 Oct 29, 1909

24,385

Aug 29, 1903 12,879 Aug 15, 1906 17,051 Nov 20, 1906 18,092

Nov 28, 1906 17,287

Jan 11, 1907

19,261

Melting Furnaces Sep 19, 1903 13,040

Oct 20, 1904

14,585

Jan 12, 1905

15,349

New instrumental approach to electric discharges using magnetic ﬁelds between the permanent electrodes to produce fast and intense arcs Furnace for dissociation of atmospheric gasses Electric furnaces for oxidation of nitrogen Different gas reactions using electric arcs New design for circulation of air in electric stoves by using a plasma torch Increased energy in electric furnace A new approach to obtain higher yields and increased concentrations of nitric acid with furnaces using larger arcs generated by magnetic ﬁelds Method to transform nitric acid into saltpeter, calcium nitrate Absorption system to produce nitrogen oxide Method to utilize patent 17,051 in another way to produce similar products New methods for absorption system to produce nitrogen o oxides New methods to oxidize different g gasses

Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland

Kr. Birkeland Kr. Birkeland

Kr. Birkeland and Sam Eyde Kr. Birkeland Kr. Birkeland

Kr. Birkeland

Kr. Birkeland

Method to reduce or oxidize Kr. Birkeland and solid matter using of a plasma Sam Eyde torch Furnaces for hard-to-melt Kr. Birkeland and metals and minerals Sam Eyde New design for melting furnace Kr. Birkeland and Sam Eyde

198

APPENDIX 3

Date

Patent Number Short Title

Patent Holder(s)

Apr 01, 1905

18,243

Apr 02, 1906

19,272

Kr. Birkeland and Sam Eyde Kr. Birkeland and Sam Eyde

Jan 11, 1907

19,635

Electric melting and metallurgical processes New approach to the treatment of different metals during melting New approaches and tools for the treatment of different metals and minerals during melting Methods and instruments for propagation of electric waves from a transmitter to same rreceiver unperturbed by the presence other waves Electrodes for magnetic wave propagation using the plasma torch in radiotelegraphic apparatus Methods to produce radiowave oscillations Radio receivers An instrument for radio telegraphy and telephony An instrument to generate rradiowave oscillations New equipment to start and stop high voltages in engines and control high voltages in general circuits g

Kr. Birkeland

Radio-wave Propagation Dec 18, 1906 17,557

Mar 15, 1907 17,558

Mar 26, 1907 17,559 Sept 05, 1907 17,975 Sept 23, 1907 17,370 Oct 03, 1907

17,974

Apr 04, 1907

17,499

Hardening of Oil Mar 15, 1912 24,371 May 16, 1912 24,288 Jul 05, 1912

24,471

Jun 06, 1913

24,472

Jun 18, 1913

24,470

Method to reﬁne and use whale oil Methods to harden different oils

Kr. Birkeland and Sam Eyde

Kr. Birkeland

Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland Kr. Birkeland

Kr. Birkeland and Olaf Devik Kr. Birkeland and Olaf Devik Methods to harden different oils Kr. Birkeland and using pressurized hydrogen Olaf Devik New methods to harden different Kr. Birkeland and oils Olaf Devik Methods to transform oil to fat Kr. Birkeland and with higher melting-point oils Olaf Devik using hydrogen under pressure

PATENTS A

199

Date

Patent Number Short Title

Patent Holder(s)

Bismuth Feb 21, 1912

23,542

Methods to produce ammonium nitrate Methods to produce calcium saltpeter while extracting metals Methods to extract clean metals

Kr. Birkeland

Method to feed humans and animals with chemical materials and reaction monitoring equipment New method to treat organic waste products, such as garbage, and cadavers of g different animals New approach to electric melting and reduction stoves A method to produce clean metals from sulphurous products

Kr. Birkeland

Dec 04, 1912 24,423

Dec 23,1912

26,329

Miscellaneous Patents Apr 30, 1910 21,334

Jan 11, 1912

23,446

May 04, 1912 26,865 Dec 12, 1912 26,329

Kr. Birkeland

Kr. Birkeland

Kr. Birkeland

Kr. Birkeland Kr. Birkeland

APPENDIX 4

LETTERS

LETTER: BIRKELAND TO KAJA GEEMUYDEN Paguebot Paul, Locat. 4 April 1917

Dear Kaja, We are on the leg of our journey from Colombo to Singapore. Dr. Eriksen (Holth’s friend, and the Danish General Consul) and I plan to visit China and Japan, countries we both have dreamed about, before continuing our journey home via Vladivostok. While I still do not know my traveling companion very well, he gives the impression of being a warm hearted and good man, who is also intelligent. He is married to a magniﬁcent and unusual lady who is three-quarters Norwegian (Blackstad family). She and Eriksen are both eye specialists. I am very much looking forward to seeing my friends in Kristiania again. As usual for me, I came to Egypt full of conﬁdence in everybody and everything. However, for the ﬁrst time in my life I learned than one must not give blind conﬁdence to new friends because they can, if they are successful, deceive you more than your most dangerous enemies. Most of all I long for my natural home to continue my work and to write of my Odyssey, w which will be ﬁled in a secret archive. I have recently experienced things in Egypt that cannot be discussed openly. I can perhaps convey them verbally to selected loyal, and well-tested friends, of which I don’t have many. Together we can try to ﬁgure out what has really happened; this is of utmost interest to me. I believe some of the most virulent people live in Egypt. They lie and deny facts. During the war this became worse than before. Egyptians use every means available to hurt suspicious Englishmen who are in “the water up to their heads.” My impression is that I have undergone much suffering through the fault of France, the country we have loved the most since childhood.

202

APPENDIX 4

In your last letter you said that you have not seen (Karl) Devik recently. I hope that by now you have had a chance to meet him. You should be very friendly toward him because he is certainly an excellent man. With the most friendly regards W Yours sincerely Y Kr. Birkeland Translated by A. Egeland. T

LETTERS

203

EXTRACTS FROM TERADA’S DIARY CONCERNING KRISTIAN BIRKELAND IN MAY–JUNE 1917 Translated from Japanese by N. Fukushima 19 May (Saturday) 24 May (Thursday)

28 May (Monday) 29 May (Tuesday)

30 May (Wednesday)

31 May (Thursday)

I received a letter from Prof. Birkeland in Hotel Fujiya at Miyanoshita, Hakone. Birkeland wrote me that he would like to move to a hotel near our university; I recommended the Ueno Seiyˆoˆ ken. In his reply Birkeland wrote that he would move soon to Seiyˆoˆ ken. Birkeland came to our university. He seemed to have come to the Seiyˆoˆ ken the day before. I presented to him a copy of my recent paper on geomagnetism. Prof. Nagaoka (Dean of the Science College) told me that when he visited Birkeland in the morning, his actions and words were extremely abnormal, and very excited; he spoke about his dissatisfaction with the British government. Prof. Nagaoka felt as if Birkeland might commit suicide. I will visit him tomorrow morning to see what we can do for him. I visited Birkeland this morning. I heard that he collapsed yesterday morning, and had him examined by the Norwegian Minister’s physician. He was still sleeping, so I came back to the University to discuss the situation with Prof. Nagaoka. In the afternoon I went to him again with Dr. Miura (of the Medical College); he said that Birkeland seemed to have been poisoned by a large dose of a sleeping drug. After Dr. Miura left Birkeland told me about harassment he had [received] from the British authorities in Egypt. His story sounds like the Odyssey, as Birkeland calls it. He told me that he knew that a British detective had been watching him in Hakone. Birkeland said, “I am too tired. So I took eight tablets to ﬁnish them all.” This evening, in the rain, I visited Prof. Nagaoka to relate all I had heard directly from Birkeland.

204 1 June (Friday) 3 June (Sunday)

4 June (Monday)

8 June (Friday) 9 June (Saturday) 15 June (Friday)

16 June (Saturday) 17 June (Sunday) 21 June (Thursday)

22 June (Friday)

APPENDIX 4 Prof. Nagaoka visited Birkeland this morning and saw that he was recovering rather quickly. This morning I heard that Birkeland had come to my room in the university; I went immediately to the Seiyˆoˆ ken. Prof. Nagaoka also came to visit him. Birkeland came to the university in the morning; he borrowed from me papers by van Bemmelen and Bildingmeier. A telegram was sent to the Zikawei Observatory asking for its report on aurora. Birkeland came to me in the morning; he took with him a paper by Størmer. He came again in the afternoon. Birkeland came to me in the morning; we ate lunch together at the University. In the morning I received an urgent call from the Seiyˆoˆ ken informing me that Birkeland was in critical condition. I went to the hotel immediately along with Dr. Miura, the Norwegian Minister and Prof. Nagaoka. We heard that last night he took eleven grams of veronal, possibly with the intention of committing suicide. Although his breathing had already stopped Dr. Miura and his students tried artiﬁcial respiration on him for about an hour without success. We requested an inspection by the police, and his body was then transported to the Department of Anatomy in our university. We decided to keep his body for awhile in the university (until we receive a reply from Norway to the Minister’s telegram). In the afternoon I sent a wreath of ﬂowers to be placed on Birkeland’s cofﬁn. At the university Prof. Nagaoka and I discussed our funeral address for Birkeland and other matters. Since the funeral ceremony will be held at the German church in central Tokyo at 14:30 next Monday, the invitational circular was sent to concerned people including the staff of the Central Meteorological Observatory. This morning Birkeland’s body was placed into a cofﬁn and transported to the church.

LETTERS

205

LETTER: TERADA TO BIRKELAND (WRITTEN IN ENGLISH) May 19, 1917 Science College Imperial University Tokyo, Japan

Dear Professor Birkeland, I am very happy to learn that some of the phenomena I have studied show an intimate relation with the results of your valuable investigation on zodiacal light. I am very much interested and will be glad to learn more details about it. The problem which puzzled me is what determines the magnitude of the period of the most frequent waves. I will be pleased to learn [your] opinion about it. In spite of thorough inquiries in the main library of the University, the second volume of your paper could not be found at last. I am inﬁnitely sorry for it. I will continue searching, but with little hope. How are you getting along in Hakone? I hope you will soon get over the trouble. With kindest regards, I remain W Yours very truly Y T. Terada T

206

APPENDIX 4 LETTER: TERADA TO BIRKELAND (WRITTEN IN ENGLISH)

May 24, 1917 Science College Imperial University Tokyo, Japan

Dear Professor Birkeland, I am very glad to learn you are getting better and intending to take a lodging near us. There is a Hotel, Seiyˆoˆ ken in Ueno Park (not the one with the same name in Tsukiji), which is within 15 minutes walk from our College. It is situated in the green forest near the edge of a wooded terrace and seems to be quite good for health. The lodging will cost 6.5 to 7 Yen in all. It will however be better to settle the matter after you have seen if the room will ﬁt you. We will be all very glad to have you coming near us. With kindest regards W Yours sincerely Y T. Terada T

LETTERS

207

LETTER: NAGAOKA TO BIRKELAND (WRITTEN IN ENGLISH) May 24th, 1917 Science College Physical Institute Imperial University Tokyo, Japan

Dear Professor Birkeland, We are nowadays welcoming numerous foreign guests from every part of the world, but among a host of tourists it is very rare to ﬁnd a world-renowned physicist as you are. It was therefore with no little surprise that I was apprized of your arrival. I told the rector of the University of your visit to the Physical Institute; he regretted very much not having seen you. If you will return to Tokyo and care to come to the University again, the rector desires to invite you to Tifﬁn, where a number of professors in physics, electrotechnics and electrochemistry, w will also be present. He lets me ask you when it will be convenient for you. We shall be very happy if you will take the trouble by that occasion to give a lecture of an hour or so to graduates and students of physics on any subject you like to choose. Mr. Terada tells me that you intend to come to Tokyo and lodge in the neighborhood of the University; I should like to recommend to you Seiyoken on the margin of Uyeno Park about a kilometer distant from our institute. Expecting to see you in Tokyo and waiting for your answer, I remain Yours faithfully Y H. Nagaoka

208

APPENDIX 4 LETTER: TERADA TO BIRKELAND (WRITTEN IN ENGLISH)

May 31, 1917 Science College Physical Institute Imperial University Tokyo, Japan

Dear Prof. Birkeland, I can see now quite well how unhappy you must have been in Egypt. I am inﬁnitely sorry for it. Now you are among us the scientiﬁc men who are brethren all over the world, are they not? You can be quite assured that we all esteem you as one of the distinguished members of the scientiﬁc world and [are] very glad to have you staying near us. I do not believe that any persecution of the kind you imagine may continue to bother you. Here it is so peaceful that you will perhaps notice yourself in (the) course of time. If you have still anything you may feel uneasy or nervous (about) please let us know about it straightforward. Prof Nagaoka and I will try anything to make it all right and make your sojourn among us as easy as possible. Please write to us anything you have to complain against the Hotel etc. Prof. K. Miura is the best man of the faculty. You will soon get over your illness if you would trust him and follow his prescription. We will come and see you by and by. Take the best care of your health. You will be soon quite happy as ever. Yours very truly Y T. Terada T

LETTERS

209

LETTER: NAGAOKA TO BIRKELAND (WRITTEN IN ENGLISH) May 31st, 1917 Science College Physical Institute Imperial University Tokyo, Japan

Dear Professor Birkeland, I have the pleasure of introducing Professor K. Miura of the medical faculty. He is perhaps the best medical man that I can recommend for curing your illness. Professor Miura is versed in German, French and English languages, but he will prefer the ﬁrst mentioned. Hoping for your rapid recovery I remain Yours very truly Y H. Nagaoka

210

APPENDIX 4 LETTER: GERDA THOMSEN TO KARL DEVIK

Translated by A. Egeland

Dear Devik, Finally a letter from you (polite form) reached Egypt; it was on the way for a long time, before it arrived. You asked my husband for news about Prof. Birkeland but since he has been fully occupied, he asked me to answer you. Last autumn I visited the Professor a few times; he was very busy with some new instruments and with a letter he received from the British Admiralty. He was somewhat excited and told me that he drinks a lot of coffee in order to work without becoming tired. He told our Ambassador and informed us that his work would soon be ﬁnished and it did not pose any danger to him. This, I believe, occurred near the end of October. One evening around New Year’s day Dr. Røder came by. He had been in Helwan to see a patient then visited the Professor. He came to us very concerned and asked us if we could go with him to see the Professor. He and I went there the next evening together with Mustachi, and Marie (both from National Bank) who were the only people he trusted. He was quite worn out, thin, his eyes were ﬂickering and he showed a marked paranoia. He felt that the English were after him in some way; he was completely disconnected from the world. The English run around the house day and night. They had spies everywhere; among them was his housekeeper, whom he ﬁred about a month ago. He did have some medicine: “With a half beer glass of whisky and two grams of veronal, nothing frightens you. You can ﬁght like a lion.” He was very pleased to be among Scandinavians who speak his language, but he was markedly changed. He had two dogs. His garden was closed to everyone, and he had revolver and a shotgun ready for use in the bedroom. Poor Birkeland, he has had a bad time. The next day my husband went out there and found him much better. However, we cannot visit him every day, the trains are slow and few. We suggested that he move to live next to us in a guesthouse. This was a signiﬁcant change that allowed us to see him a few times every day. Dr. Røder treated him; he would lie quietly in bed, would sleep and eat, and eventually looked on whisky with disgust and a violent dislike. My husband had a strong soothing effect on him and they went for walks together. Once again the Professor could enjoy himself and laugh like in the old days. When he was

LETTERS

211

out of bed we would eat together and his appetite was excellent. His perception of people as being threats to him did not disappear, but it grew steadily weaker. He felt well protected here because my husband was a diplomatic agent. He regarded his own consul and in particular the deputy, among the worst “spies.” He steadily improved and wanted to start working, but could not. He was like a child who could not be left alone for long. Constantly he was thinking about how he could get back to Norway. Staying here for another summer was unthinkable, and traveling home via England was impossible. One evening while we were talking, I spontaneously suggested, “Why don’t you travel the other way via the Far East?” He was immediately enthusiastic, but said that he could not travel alone. Again his spirit deﬂated slightly as he considered who could travel with him. I then suggested my husband had been thinking about a trip home. He was delighted, and the decision was made. The next day at the shipping ofﬁce, everything was planned and arranged. A lot of things happened in these days. My husband has a diplomatic passport and from his travel company he received special recommendations and advice on getting the best treatment in the different countries through which they would pass. In a very short time after the travel was decided, he was nearly the same as in the old days. He attended two small parties where he was full of life and very amusing. Everyone at the guesthouse loved “monsieur le Professur.” Nobody was aware of his sickness. Finally on 10th March they departed from here. He radiated with happiness and promised me to drown all “English spies in the Red Sea.” My husband said that he kept his word. After Colombo spies were no longer mentioned. They had an enjoyable voyage. What a shame it should end so sadly for Professor Birkeland. If you could respond and tell us how it happened, we would be very thankful. Ambassador Anker has not answered our letters or telegrams. When the professor decided not to travel home, my husband gave him (Anker) an accurate description of the situation, but he seemed to ﬁnd my husband strange and did not take the situation seriously, but promised to take care of the Professor while he was in Japan. I was very sorry when I heard that he was dead. Mrs. Hooker (the wife of the Norwegian consul) informed me. Of course after that I had to give her the keys and let her make the decisions about the house and garden. They seem to have rented it out for the winter and that is just as well. Yes, the poor professor had a very difﬁcult time, and I have often blamed myself Y for not visiting him sooner. The cause of his sickness, I believe, was a combination of hard work, abuse of coffee and later of whisky and veronal. There were other circumstances as well. First, he felt that he was under surveillance,

212

APPENDIX 4

and we cannot be sure that this was not true. However, his life was never in the danger he thought. He had been in contact with the (British) headquarters here. Although they had been obliging, he thought that they were just trying to give him a false sense of security. The second point, which was very difﬁcult for him, was that since October or early in November, he received no communications from you. Until he left, no news arrived even though he and my husband sent several telegrams to you. He constructed all kinds of hypotheses, although the only real explanation was censorship. In addition, he had difﬁculty surviving our unusually warm and humid weather. It is a terrible misfortune and a sorrow for everyone who knew him, that he should die so young, alone and in a far off country. You can understand that it is very sad for us, and particularly for my husband, who left him there. However, everyone advised them against traveling home, especially the Professor because of the cold weather and darkness. He was so pleased to ﬁnd a Norwegian (Anker) ffamily, who promised to take care of him. He lived together with them up in the mountains, while my husband was traveling. He also made preparations to resume his work, having met Japanese professors who were old acquaintances. Thus, my husband believed that he was in good shape. We are pleased to hear that your work has lead to positive results, and we hope, once again when you have time let us hear from you. Let us hope that the war ends soon so that we may see you here again next winter! With kind regards from my husband. W Y Yours, Gerda Thomsen

LETTERS

213

LETTER: ERIKSEN TO BIRKELAND Translated by A. Egeland May 18, 1917 Hotel Pleasanton Yokohama

Dear Birkeland, We did not succeed in seeing each other again this time. I am of course interested in knowing what your arrangements will be; whether you will travel home or stay in Japan this summer. My address the day after tomorrow: P. Leakt, M. M. Kobe and a few days later: Consul General of Norway, Shanghai, where I will greet Mr. Eitzen and family. I sent this letter to the Norwegian Legation in Tokyo, because I believe that is the most secure address. A few hours after eating dinner I will go aboard the Pane Licit at 8 o’clock. When we lay over the whole day after tomorrow in Kobe, I will try to visit Kyoto. I was in Tokyo yesterday and with General Consul Wadsted and saw some places I have not seen earlier. Early today I travelled by train to Kamokura and met with Wadsted again. If needed, charg´e d’affaires Fevrell is still interested in helping you with tickets. Finally, then I say good-bye and wish you well and thank you for your pleasant company over nearly four months and hope that we will meet again in the not too distant future. Yours sincerely, Y Eriksen Note: This letter was found in the Seiyˆoˆ ken Hotel, Tokyo and was returned via the Norwegian embassy. On the back of the envelope Birkeland wrote by hand: “Dr. Eriksen is a most valuable diplomat and other documents are found in my house in Helwan.”

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INDEX OF NAMES

Aars, Jonathan, 19, 22, 133, 137 Abel, Niels Henrik, 21–2, 24 Adler, Hanna, 157 Akasofu, Syun-Ichi, 80, 176, 178 Alexander, Anton, 24 Alfv´e´ n, Hannes, 77, 81, 83–5, 173, 176, 178 Amundsen, Roald, 156, 162 Andersen, Kjetel Gjølme, 215 Anker, Peder Bernt (Ambassador), 149, 150, 152, 153, 154, 163, 211, 212 Appell, Paul-Emile, 23 Appleton, Edward V., 16 Aristotle, 13 Armstrong, James, 105, 173 Arrhenius, Svante A., 49, 49n. Bamberger, Max, 139 Bartels, Julius, 14, 73 Bavalet, Louis, 48 Bergius, Friedrich, 119 Birkeland, Ida Charlotte (f. Hammer), 3, 143, 144, 145, 157, 163 Birkeland, Ingeborg, 17 Birkeland, Reinert, 17–8 Birkeland, Richard, 18–9, 156, 163, 166, 175, 189 Birkeland, Tønnes Gunnar, 17–9, 22, 142, 153–4, 161–4, 190 Bjerknes, Carl Anton, 13 Bjerknes, Vilhelm, 13, 22–3, 27, 60, 79, 141, 156, 159, 161, 191 Bødtker, Henning, 156, 163 Bohr, Niels, 8, 127 Borisoff, Alexander, 63 Børresen, Admiral Urban J. R, 116 Bosch, Karl, 119 Bostrom, ¨ Rolf, 171 Boye, Elisar, 53–5, 65, 132 Bredal, Johan O, 118, 144, 155–6, 162–3 Brøgger, Waldemar Christopher, 25, 110, 134, 139, 190 Brundtland, Terje, 39, 40 Bryn, Alfred, 129 Bull, Anders Henrik, 129, 131

Carlheim-Gyllenshøld, Vilhelm, 140 Cassini, Giovanni, 94 Celsius, Anders, 14, 167 Chapman, Sydney, 13, 73, 76, 77, 80, 81, 82, 83, 84, 165, 168, 170 Coleman, Catherine, 178 Collett, John Peter, 215 Cook, James, 13 Cowley, Stanley, W. H., 177, 179 Crookes, Sir William, 109, 185 Curie, Marie, 6, 130 de Marian, Jean Jacques Dorto`u` s, 48 Dessler, Alexander J, 85, 141, 173, 176 Devik, Karl, 6, 9, 18, 35, 38, 43, 96, 97, 142–3, 145–7, 149–51, 158, 163, 176, 189, 202, 210 Devik, Olaf, 6, 9, 10, 18, 32, 35, 53, 78–9, 105–6, 123, 126, 128, 131–2, 134, 143–5, 154–6, 158–9, 163, 166, 175–6, 178, 189, 194–5, 198 Dietrichson, Jørgen, Ludvig, 32, 35, 158 Dungey, James, 170 Ege, Ingeborg Susanne, 17 Egeland, Alv, 13, 84, 176, 210, 213 Egenæs, Olaf, 61 Einstein, Albert, 127, 167 Eriksen, Justinius (Generalconsul), 143, 148, 150, 151 Eriksen’s wife; see Gerda Thomsen Eyde, Sam, 9, 110–24, 129, 138, 139, 145, 156, 175, 187, 189–98 Fabricus, Johan J., 60 Falsen, Consul, 63 Faraday, Michael, 14 Falthammer, ¨ Carl-Gunne, 173 Friedman, Robert Marc, 138, 139 Fritz, Herman, 15 Fukushima, Naoshi, 8, 77, 81–2, 170, 176 Gaimard, Paul, 48 Galileo, 13, 14

220

INDEX OF NAMES

Gassendi, Pierre, 13 Gasslander, Olle, 124, 140 Gauss, Carl Friedrich, 13, 15 Geelmuyden, Hans, 13, 161 Geelmuyden, Kaja, 18, 150, 157, 161, 189 Gilbert, William, 13 Glazebrook, R. T., 106 Gleditsch, Ellen, 6, 130, 157 Goldschmidt, Heinrich Jacob, 139 Goldstein, Eugen, 16 Grimnes, Ole K., 216 Guldberg, Alf, 24 Guldberg, C. M., 160

King H˚a˚ kon VII, 5, 11, 121, 133, 162 King Kristian IV, 1n. King Oscar II, 3, 4, 11, 52, 104, 137 Kirchoff, Gustav Robert, 172 Klason, Peter, 139 Knox-Shaw, Harold, 96, 145, 163 Knudsen, Gunnar, 60, 103, 104, 110–1, 156 Koren, Johan, 63 K Korsakoff, Rimski, 63 K Krag, Ole Herman, 103, 104 Krekling, Richard, 61, 63–4 Krogness, Ole Andreas, 6, 9, 67, 78–9, 92, 95, 97–8, 131, 154, 156, 160, 163, 166, 194

Haber, Fritz, 119 Hagerup, Harald, 62 Hagerup, Johan, 62 Halley, Edmund, 14, 92, 167 Hammer, Ida Augusta Charlotte, 3, 143 Hansen, Alf Scott, 139 Hansteen, Christofer, 13, 14, 15, 21, 167 Harang, Leiv, 131 Harendel, ¨ Gerhard, 177 Hartree, Douglas R., 16 Heaviside, Oliver, 16 Heitman, Johan, 46 Helland, Amund, 146, 156, 161, 162, 175, 189 Helland-Hansen, Bjørn, 47 Henriksen, Noralf, 12, 119 Hertz, Heinrich, 22, 23, 24, 28, 141, 159, 167, 168, 191 Hiorter, Olaf Peter, 14, 167 Holmboe, Carl Fred, 131, 135 Holst, Elling Bolt, 19, 20–22, 24, 52, 156, 191 Holst, Helge, 122 Huygens, Christian, 27

Lange, Richard, 54 Langmuir, Irving, 29, 169 Laplace, Pierre-Simon, 15 Lemstrøm, Karl Selim, 50 Lenard, Philippe E., 24 Lie, Sophus, 24, 156 Lodge, Sir Oliver, 156

Ibsen, Henrik, 24, 135 Iijima, Takesi, 174 Isaachsen, Daniel, 145, 175

Oguti, Takasi, 177 Olden, Ole F., 126 Olsen, Kristian Anker, 215, 218 Ørsted, Hans Christian, 13, 14

Jago, Lucy, 10, 106, 142–3, 147, 156 Jones, George, 95 Joule, James Prescott, 172 Keilhaug, Wilhelm, 217 K Kennelly, Arthur E., 16 K King Frederik VI, 12

Mann, John, 152 Marconi, Gulielmo, 16 Maxwell, James Clerk, 2, 14, 167 Miura, Dr. K., 152–3, 203–4, 208–9 Mohn, Henrik, 13, 62, 143, 156, 159, 160 Mørner, Countess Anna Ulrika (Ulla), 124 Muir, Jessie, 67 Næss, Eivind Bødtker, 113 Nagaoka, H., 149–54, 203–4, 207–9 Nansen, Fridtjof, 3, 11, 47, 59, 105, 134, 137, 156, 160, 162 Newton, Isaac, 27, 85 Nordberg-Schultz, Thorvald, 101

Pauersson, O., 140 Paulsen, Adam, 49, 50 Peratt, Anthony L., 120, 165, 177 Perrin, Jean, 33 Persson, Niels, 114, 116 ´ Picard, Emile, 23

INDEX OF NAMES Planck, Max, 177 Poincar´e´ , Henri, 22–3, 32, 156–7, 167 Potemra, Thomas A., 174, 176 Quale, Anders, 48 Rayleigh, John W. Lord, 106, 156 Riddervold, Hans, 63, 65–6 Riiber, Claus Nissen, 30, 113, 115, 131, 167 Rive, Lucien de la, 23 Rødseth, Jørgen, 112 Roeder, Louis, 142, 149, 150 Rontgen, ¨ Wilhelm Conrad, 126 Roux, Alan F., 178 Russeltvedt, Nils, 62–3 Rutherford, Ernest, 8, 127 Sæland, Sem, 6, 7, 9, 34, 52–3, 55, 61–2, 64, 78, 105, 132, 134, 142, 154, 156–8, 166, 175, 189, 193 Sander, Lady, 106, 189 Sarasin, Edouard, 23, 25, 27, 28, 181 Schaaning, Hans Thomas, 63, 65 Schiøtz, Oscar Emil, 13, 22, 126 Schlosing, Dr. Alphones Th´e´ ophile, 115 Schonherr, ¨ Otto, 113, 118, 139, 190 Schuster, Arthur, 80, 96, 98, 145 Schwabe, Heinrich, 14 Scott-Hansen, Alf, 139 Shaw, H. Knox, 96, 145 Skolem, Thoralf, 6, 96, 131, 145, 147, 149, 166, 186 Sohlman, Ragnar, 139, 190 Southwood, David, 177 Spandonides, Hella, 146–7, 157 Stewart, Balfour, 16 Størmer, Carl, 6, 9, 19, 41–3, 97–9, 140, 145, 149 Sugiura, Masahisa, 80

221

Tanakadate, Professor, 151 T Terada, Torahiko, 143, 149–55, 203, T 205–8 Thompson, Silvanus, 115 Thomsen, Gerda, 148–51, 157, 163, 189, 210–2 Thomson, Joseph John, 8, 34, 34n., 101 Thomson, William (Lord Kelvin), 8 Tillberg, Knut, 114, 116 Topfer, ¨ Otto, 51, 61 Tromholt, Sophus, 15 T Van Allen, James, 176 Vasyliunas, Vytenis, M., 171–2 V Vegard, Lars, 6, 67, 131, 155, 156, 160, 161, 166 Verne, Jules, 1 Vestine, E. H., 80–2 V Vogt, Johan Hermann, 139 Voss, Thomas A., 19, 22, 133, 137 V Waage, Peter, 20 W Wallenberg, Knut, 116–7, 126–7, W 192 Wallenberg, Marcus, 110, 114–7, 123–5, W 126–7, 129, 139, 156, 190–2 Wallenberg, Raoul, 123 W Wendelboe, Per, 123 W Wereide, Torstein G., 166 W Weyprecht, Carl, 45 Wiechert, Emil, 34 W Wilkan, Steinar, 218 W Witt, Otto, 115 W Wriedt, Madame, 155–6 Zeuthen, Georg, 19 Zelgenyi, Leo A., 178 Zmuda, A. J., 173

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