From Alchemy to Chemistry:
Five Hundred Years of Rare and Interesting Books

University of Illinois at Urbana-Champaign
Rare Book Room Exhibit

KIRWAN, RICHARD (1733 - 1812). An Essay on Phlogiston, and the Constitution of Acids. London, 1787.

The Irish scientist Kirwan was one of the very last supporters of the phlogistic hypothesis. He was a brilliant but eccentric man. On account of his delicate health, he wore his hat and overcoat indoors (as shown in his portrait in the Royal Dublin Society) and because of a weak throat lived on ham and milk. One of Kirwan's most interesting books is his defense of the phlogiston theory. First published in 1787, the Essay defended the phlogiston theory against the views then being promulgated in France by Lavoisier and his followers. Kirwan identified phlogiston with "inflammable air" (hydrogen), comparing it with "fixed air" (carbon dioxide). He did not deny the observations on which Lavoisier had based his rejection of phlogiston, but believed them to be explicable in terms of the older theory, which on the whole, accorded best with known chemical facts. Many of the arguments used by Kirwan in his Essay on Phlogiston depend on apparent contradictions between reactions postulated by the antiphlogistic theory and the regular order of affinities of substances. De Morveau says that Kirwan's questions 'are equally embarrassing on every hypothesis, the solution of which appears to depend upon a concurrence of affinities not yet proved, which offer, in a word, matter for new researches, but are not, for that reason, real objections'. Kirwan abandoned the phlogiston theory in 1791 because he failed to show conclusively the formation of fixed air from phlogiston and oxygen. He was converted by Madame Lavoisier's translation into French of Kirwan's Essay on Phlogiston; Lavoisier or one of his associates added a refutation at the end of each of the thirteen sections.

DSB; Partington III, pp660-665.

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