530 Royal Society. 



in various scientific journals ; and the general results of all his re- 

 searches and discoveries were exhibited, in a systematic form, in 

 his well-known work Sur le calorique rayonnant, which M'as pub- 

 lished in 1809, and in which he fully developed his Theory of Ex- 

 changes, and was enabled to give a consistent explanation of the 

 principal facts which were at that time known respecting the nature 

 and propagation of heat. 



It would be impossible, in the very short compass within which 

 this notice is necessarily confined, to enumerate even a small part 

 of the publications of an author whose pursuits were so various 

 and whose labours were so unremitting. He contributed papers 

 to our Transactions in 1797 and 1803; the first containing an ex- 

 planation of some optical experiments of Lord Brougham, and the 

 second, some remarks on heat and on the action of bodies which inter- 

 cept it, with reference to a paper by Dr. Herschel* ; and in 1806, he 

 became one of the foreign members of our body. In 1799, he ob- 

 tained the first accessit for an essay Sur Vinjluence des signes rela- 

 tivement a la formation des ideas, which was written for a prize, 

 adjudged to the celebrated Degerando, proposed by the Institute 

 of France ; and he was shortly afterwards elected a corresponding 

 member of that body. His Essais de philosophic, et etudes de I'esprit 

 humain, appeared in 1804, to which were appended some very re- 

 markable Essays of his friend and ancient preceptor Le Sage, of 

 whom he published a most interesting life in the following year. 

 He likewise published, in very rapid succession, translations of the 

 Rhetoric of Blair, the Essays and posthumous works of Adam Smith, 

 the Elements of Philosophy of Dugald Stewart, the essay on Popu- 

 lation by Malthus, Salt's Travels in Abyssinia, the Conversations on 

 Political Economy, of his wife's sister-in-law, Mrs. Marcet, and many 

 other works of less importance and interest. 



In 1823, at the age of 72, though still vigorous and active both 

 in body and mind, he resigned the professorship of natural philo- 

 sophy, in wise anticipation of the approach of that period of life 

 when men naturally feel reluctant to acknowledge the decline of 

 their faculties, or incompetent to perceive it. From this time, 

 though still consulted by his colleagues and fellow-citizens on every 

 important subject connected with the Academy or the state, he re- 

 tired into the bosom of his family, which contained within itself, in 

 a very uncommon degree, every element of tranquillity, contentment 

 and happiness. His own temper was singularly equable and tran- 

 quil ; and his tastes and pursuits, which rarely left his time unoc- 

 cupied, saved him from that tcsdimn vita which sometimes renders 

 old age querulous and discontented. Thus happily disposed and 

 happily circumstanced, it is not wonderful that his life should have 

 been prolonged beyond the ordinary limits of humanity. He died 

 on the 8th of April, in the 88th year of his age, suiTounded by his 

 family, and deeply regretted by all who knew him. 



The philosophical character of M. Prevost had been greatly influ- 



[* See Phil. Mag., First Series, vol. xiii. p. 291.— Edit.] 



