From Elements To Atoms: A History Of Chemical Composition

TRANSACTIONS of the AMERICAN PHILOSOPHICAL SOCIETY Held at Philadelphia For Promoting Useful Knowledge, Volume 92, Pt. 4 From Elements to u/Itoms: A History of Chemical Composition Robert Siegfried American Philosophical Society Philadelphia. oo2002 Societyfor itS Copyright(C)2002 by the AmericanPhilosophical serles. Transactons All rightsreserved. ISBN: 0-87I69-924-9 US ISSN:oo65-g746 Data Libraryof CongressCataloging-in-Publication Siegfried,Robert,I92IFromelementsto atoms:a historyof chemicalcomposition/ by RobertSiegfried. Society, of the AmericanPhilosophical p. cm. (Transactions 4) pt. 92, v. ISSN oo65-g746; and index. references Includesbibliographical (pbk.) ISBN 0-87I69-924-9 Atomictheory-History. I. Title. II. Series. QD46I * S463 2002 54I . 2-dC2I 2002038 Designand composition AndrewL. Sihler S8I CONTENTS Preface v Introduction One: The SeventeenthCentury: ChemistryComesofAge 24 Two: Robert Boyle: The Sceptical Chymist 42 Three: The Stagnation of Chemical Theory: 1675-I75o 56 Four: The Development of the Idea of Neutral Salt 74 Five: An HistoriographicDigression: Phlogiston I00 Six: How Air Returnedto Chemistry: A Brief History ofAir i6oo-i75o 114 Seven: The Return of the Four Elements I 27 Eight: French Chemistrycirca I760 139 Nine: The Marriage of Air and Phlogiston 152 Ten: Lavoisier and the Anti-PhlogisticDoctrine 163 Eleven: A CompositionalNomenclature 183 Twelve: A ComparativeView of the Phlogistic and Anti-Phlogistic Philosophies 194 Thirteen: Assimilation and Anticipation 213 Fourteen: John Dalton and the ChemicalAtomic Theory 234 BIBLIOGRAPHY 265 INDEX 275 PREFACE T HIS BOOK was first conceived, and some portions written, for the stu- dents in the class of history of chemistry that I was teaching during the I980s following the retirement of Aaron J. Ihde at the University of Wisconsin. My aim in teaching these chemistry and pre-med senior students was to enlarge their understanding of the nature of chemical science and explain how the concepts they were learning in their chemistry classes came to be. It is both to those students and to Aaron Ihde that I owe the inspiration for this attempt to present a simple, readable account of how in the eighteenth century chemical composition slowly abandoned the centurieslong tradition of metaphysical elements of EARTH, AIR, FIRE, and WATER, or the Paracelsanvariation of MERCURY, SULPHUR, and SALT.By the end of the eighteenth century, chemical composition had become expressible in terms of operationally defined material simple bodies made verbally explicit by Lavoisier'ssuccessful new chemistry, wherein the elements were defined as any body not yet shown to be compound. Just twenty years after Lavoisier,John Dalton introduced the concept of atomic weight unique to each simple body, from which came the modern quantitative structure of chemical composition. Hence the story of the movement of chemical theory from metaphysical ELEMENTS to operationally-functional ATOMS. About thirty years ago the late Betty Jo Dobbs and I published a paper1 presenting the view that the fundamental accomplishment of Lavoisier's chemical revolution was the introduction of a material composition based 1 Robert Siegfried and Betty Jo Dobbs, "Composition: A Neglected Aspect of the Chemical Revolution," Ann. Sci. 24 (1968): 275-293. vi PREFACE on the concept of simple bodies, i.e., those that