Elements of Early Modem Physics Copyrighted material ELEMENTS OF EARLY MODERN PHYSICS J. L. Heilbron UNIVERSITY OF CALIFORNIA PRESS Berkeley • Los Angeles • London This on 1FRQ-2EG-T9S4 Copyrighted material University of California Press Berkeley and Los Angeles, California University of California Press, Ltd. London, England © 1982 by The Regents of the University of California Printed in the United States of America 123456789 Library of Congress Cataloging in Publication Data Heilbron, J. L. Elements of early modern physics. Chapter 1 and 2 reprinted with minor corrections from the author’s Electricity in the 17th and I8th centuries. Chapter 3 condenses and up- dates original account of electricity. Bibliography: p. Includes index. 1. Electricity —History. 2. Physics — History. 1. Title. QC507.H482 537'.09032 81-40327 ISBN 0-520-04554-8 AACR2 ISBN 0-520-04555-6 (pbk.) Copyrighted material 1 Contents PREFACE. vii A NOTE ON THE NOTES xi NOTE ON CONVERSIONS . xii CHAPTER I. PHYSICAL PRINCIPLES. 1 1. The scope of ‘physics,’ 1 2. Occult and other causes. 1 3. Corpuscular physics, 22 4. Attraction in Newton. 38 5. Force among the early Newtonians, 47 6. Forces and fluids. 55 7. Quantitative physics, 65 CHAPTER II. THE PHYSICISTS. 90 1. Jesuits. 93 2. Academicians. 107 3. Professors, 126 4. Independent lecturers, 150 CHAPTER III. THE CASE OF ELECTRICITY. 159 1. The seventeenth century, 160 2. The great discoveries and the learned societies, 167 3. The age of Franklin, 183 4. Quantification. 207 5. Epilogue, 233 BIBLIOGRAPHY. 241 INDEX. 285 Copyrighted material Preface There is no synthetic history of early modern science that meets contemporary standards of scope and scholarship. It would be good to have one, not only for itself but also as a buttress and correction to the rapidly growing Jiistoriography of modern science. The up-to-date synthesizer must attend to institutions as well as to ideas, to the context as well as to the content of science. A few elements of such a synthesis make up the two introductory chapters of my book Electricity in the 17th and 18th Centuries: A Study of Early Modern Physics (1979). Some reviewers have suggested that these chapters be issued separately for the use of students, or, to put the matter in a fairer light, that they be made available as an inexpensive stopgap until a closer approximation to a proper synthesis arrives. The chapters are reprinted here except for the correction of a few misprints. I have not been able to stop there. Because of the structure of the original book, examples from the history of electricity were not often included in the introductory chapters. No description of early modern physics that omits elec- tricity could qualify even as a stopgap. I have accordingly rewritten and con- densed the original account of electricity into a third chapter to complete these Elements. The rewriting enabled me to tie the history of electricity closer to general themes than the larger format allowed and to incorporate new material about the study of electricity at the Royal Society of London during Newton’s presidency. The first of the book’s three chapters presents the general principles to which physical theory at different times conformed or that otherwise mediated its de- velopment: peripatetic philosophy, corpuscularism, Newton’s attractions, New- tonian forces and fluids, the impulse towards quantification. Where the ground has been tilled before, I have emphasized application rather than analysis of principles. The chapter opens with an account of the changing meaning and scope of ‘physics’ and closes with examples of the successful mathematizing of its newer branches. These sections break new ground. The second chapter describes the institutional frameworks in which physics was cultivated in the seventeenth and eighteenth centuries. I had two purposes in mind when preparing it. The first was to show the opportunities offered and the constraints imposed by organized learning; historians of science often qualify a person as a member of this or that society, academy, or religious order, or as a professor here or there, without explaining the relevance of the affiliation (if any) to the matter at hand. The second purpose was to provide the beginnings of a vii Copyrighted material viii Preface demography of physicists, their numbers, salaries, and career goals. These fac- tors conditioned the pace and extent of study of natural phenomena at a level of support and urgency quite different from what physicists enjoy today or had a century ago. The single most important contributor to the support of the study of physics in the seventeenth century was the Catholic Church and, within it, the Society of Jesus. From about 1670 to about 1750, private lecturers played an important part in keeping up ‘experimental philosophy;’ while throughout most of the eigh- teenth century universities and academies dominated the investigation of physi- cal phenomena. I consider each group in turn, Jesuits, academicians, professors, and private lecturers. Cross-national comparisons are made where useful and practicable. Chapter III presents the case of electricity. I chose it for several reasons. Firstly, the magnitude of its advance. The subject came into existence about 1600, with an inventory of bodies able to perform electrical attraction and a mis- leading, qualitative theory of its true cause. By 1800 electricians had abandoned the search for true causes, worked out the principles of electrostatics, established the basis for a mathematical theory, and opened the vast new domain of galva- nism. In these particulars electricity was the bellwether of the flock of physical sciences created during the Scientific Revolution. Secondly and thirdly, elec- tricity was unique among branches of Enlightenment physics in amusing the public, who enjoyed seeing others shocked, and in showing, in treatments for paralysis and lightning, that science might be useful. Electricity became the ex- emplar of physical science during the eighteenth century, whence the propriety of taking its history as illustrative of early modern physics. The example brings significant new results and interpretations. Much of the historiography of early modern science has centered on the development of ter- restrial and celestial mechanics, on the spread of the ‘corpuscular philosophy,’ and on the grand cosmological disputes, or squabbles, between the sectaries of Descartes and of Newton. I find, however, that despite their disagreement over theory, in practice the Newtonian experimental philosopher thought in mnch the same terms as his Cartesian counterpart, aether being to the one what subtle mat- ter was to the other; that each side held experiment in high esteem; and that the achievement of quantification confounded the programs of both. Again, the ‘Copernican Revolution’ does not adequately represent the transition from medi- eval natural philosophy to classical physics. The bullish personality of Galileo, local jealousies, the post-Tridentine paranoia of the Roman Church, and the ap- parent bearing of scripture on questions of cosmic geometry combined to intro- duce into astronomy issues that divided men otherwise able to cooperate in the creation of a new science. Galileo’s propagandistic masterpiece, the Dialogue on the Two ChiefSystems of the World, still hoodwinks historians into believing that peripatetics contributed nothing to the Scientific Revolution but unreasoning op- position. Study of the development of electricity, which was theologically and CopyrighlGd il Preface ix cosmologically neutral, points the way to a juster estimate of the contributions, the expectations, and the changing composition of the early modem physicists. The belief, common among historians who concern themselves only with Britain and France, that university professors made only a small and continually declining contribution to natural philosophy during the seventeenth and eigh- teenth centuries also fails before the facts. Between one-third and one-half of the electricians whose work is noticed in Electricity were affiliated with universities. Preliminary study of the early histories of meteorology and thermodynamics gives a similar result. The institute of physics, usually considered an invention of the nineteenth century, may be discerned at a few leading universities at the end of the Ancien Regime. Some reviewers have found it difficult to accept the finding that not meta- physical commitments but new instruments gave the main impulse to the devel- opment of electrical theory. Their resistance is consonant with a pervasive bias in the recent historiography of science: the tendency to make general theory, or world view, or deep principle, the driving force in the growth of scientific ideas. Our case history shows that the metaphysics^ of the paradigms and research pro- grams supposed to guide scientists are seldom close enough to experimental work and theory construction to order them in useful ways. It is a pleasure again to thank P. Forman, G. Freudenthal, R. Hahn,R. Home, T. S. Kuhn, A. Quinn, and S. Weart for valuable suggestions about the origi- nal manuscript; the Universita Gregoriana (Rome), the Biblioteca Nazionale- Centrale (Florence), the Acaddmie des Sciences (Paris), the Royal Society and the British Library (London), the Royal Observatory (Herstmonceux) , the Deutsche Staatsbibliothek (Berlin), the American Philosophical Society (Phila- delphia), the Bancroft Library (Berkeley), the Yale University Library, and the Bumdy Library