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 vai4ous and whose labours were so unremitting. He contributed papers to our Transactions in 1797 and 1803; the first containing an explanation of some optical experiments of Lord Brougham, and the second, some remarks on heat and on the action of bodies which intercept 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 obtained the first accessit for an essay Sur l'influence des signes rélativement a la formation des idées, 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 philosophie, et etudes de l'esprit humain, appeared in 1804-, to which were appended some very remarkable 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 Population 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 philosophy, 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 retired 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 tranquil; and his tastes and pursuits, which rarely left his time unoccupied, saved him from that tedium vitæ 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, surrounded by his family, and deeply regretted by all who knew him.
The philosophical character of M. Prevost had been greatly influenced by that of his master Le Sage, a man of great originality and profundity of thought, but whose speculations, particularly those which attempted the explanation of the cause of gravity, trespassed somewhat beyond the proper limits of philosophy. We consequently find him disposed to explain the laws of the propagation of heat and light on the most simple mechanical principles, and to trace their origin and progress much farther than the experiments or facts will properly warrant ; thus giving to his conclusions, in many cases, a much more hypothetical character than would otherwise" have at-
