ROHAULT (JAMES), in biography, a French philosopher, was the soh of a rich merchant at Amiens, where he was born in 1620. He cultivated the languages and belles lettres in his own country, and then was sent to Paris to study philoso phy. He seems to have been a great lover of truth, at least what he thought so, and to have sought it with much im partiality. He read the ancient and mo dern philosophers; but Des Cartes was the author who most engaged his atten tion. Accordingly, he became a zealous follower of that great man, and drew up an abridgment and explanation of his philosophy with great clearness and me thod. In the preface to his Physics, for so his work is called, he makes no scru ple to say, that "the abilities and accom, plishments of this philosopher must oblige the whole world to confess, that France is at least as capable of producing and raising men versed in all arts and branches of knowledge as ancient Greece." Cler seller, well known for his translation of many pieces of Des Cartes, conceived such an affection for Rohault, on account of his attachment to this philosopher, that he gave him his daughter in mar riage against all the remonstrances of his family.
Rohault's Physics were written in French, but have been translated into Latin by Dr. Samuel Clarke, with notes, in which the Cartesian errors are correct ed upon the Newtonian system. The fourth and best edition of Rohault's Phy sics, by Clarke, is that of 1718, in 8vo. Ile wrote also " Elemens des Mathema tiques," " Traite des Mechanique," and "Entretiens sur la Philosophie." But these dialogues are founded and carried on upon the principles of the Cartesian phi losophy, which has now little other merit than that of having corrected the errors of the ancients. Rohault died in 1675, and left behind him the character of an amiable, as well as a learned and philo sophic man.
His posthumous works were collected and printed in two neat little volumes, first at Paris, and then at the Hague, in 1690. The contents of them are, 1. The first six books of Euclid. 2. Trigonome try. 3. Practical Geometry. 4. Fortifi cation. 5. Mechanics. 6. Perspective. 7. Spherical Trigonometry. 8. Arith metic.