Scottish Responses to the New Chemistry of Lavoisier

Abstract

Scottish Responses to the New Chemistry ofLavoisier ARTHUR DONOVAN How new scientific ideas are communicated and gain acceptance has emerged as a central problem in the history of science. If science is thought of as a purely objective activity governed by an explicit method, one can argue that once the inner reality of nature has been revealed, all unprejudiced observers will recognize the validity of the newly discovered truth. This simple view of scientific progress in­ volves a Manichean dichotomy that Lavoisier exploited with great skill when campaigning for the acceptance of his new system of chemistry. His attack upon the concept of phlogiston, the hypo­ thetical substance of fire and light, transformed it into a symbol of all that was wrong with the chemistry of his predecessors. Historians of chemistry have by and large followed him in saying that abandoning the concept of phlogiston was the sign of modernity in chemistry during the last two decades of the eighteenth century. More recently, however, historians and philosophers of science have emphasized that a great many factors, cultural, philosophical, political, and sociological, have contributed to the shaping of modern science. This new appreciation of the complexity of scientific progress suggests in turn that the ways in which scientific ideas are propagated need to be 237 238 / ARTHUR DONOVAN thoroughly reexamined. This is a task that historians ofthe Chemical Revolution are just beginning to address. The following account of the way several Scottish chemists perceived and responded to the system of chemistry proposed by Lavoisier seeks to advance this effort by examining a particular facet of Franco-Scottish intellectual re­ lations in the eighteenth century. We must begin, of course, by describing Scottish chemistry as it existed just before the new system of chemistry was announced. This means we must look at chemistry in Edinburgh, for while there were Scots living elsewhere who were actively interested in chemical ques­ tions, it was Joseph Black, Professor of Chemistry in Edinburgh from 1766 until his death in 1799, who gave Scottish chemistry its dis­ tinctive direction. Before assuming his post in Edinburgh, Black made two discoveries that earned him a permanent place in the Pantheon of great chemists.1 The first was that a certain part of the atmosphere combines with quicklime and neutralizes its causticity. He called this substance “fixed air” to distinguish it from common air, and in so doing inaugurated the chemical study ofthe gases ofthe atmosphere, or as it was called in the eighteenth century, pneumatic chemistry. His second discovery emerged from his investigation of the relations between quantities of heat and changes in temperature. Black found that when water, for instance, changes from solid ice to liquid water or from the liquid state to the vapor steam, it absorbs a great deal of heat that does not manifest itself as a change in tempera­ ture. He called this latent heat and concluded that in at least some cases heat is caused by a substance that enters into chemical com­ bination. It is surprising and slightly shocking to learn that Black’s assump­ tion, at the age of thirty-eight, of the chair of chemistry in Edinburgh also marks the end of his career as a creative chemical theorist. Many reasons can be given for this abandonment of a career brilliantly begun, but even in sum they fail to explain it. In 1772 Black told James Watt, “I have no chemical News, my attempts in Chemistry at present are chiefly directed to the exhibition of Processes and experiments for my Lectures, which require more time and trouble than one would imagine.” In the same letter Black characterized Scottish Responses to Lavoisier / 239 himself as a valetudinarian, and it must have been painful for John Robison to say of Black, whom he revered, “that the vigour of mind which urges on to investigation, and delights in experiment, has never been a strong feature of the doctors Character, and that he has been satisfied with a just conception of the subject, and with applying to his own purpose the observations and experiments of others. His small, very small share of health and animal spirit has long damped his scientific Ardour, and he...