Rohault, James

, a French philosopher, was the son of a rich merchant at Amiens, and born there in 1620. He cultivated the languages and belles lettres in his own country, and then was sent to Paris to study philosophy. He seems to have been a lover of truth, and to have sought it with much impartiality. He read the ancient and modern philosophers; but was most struck with Des Cartes, of whom he became a zealous follower, and drew up an abridgment and explanation of his philosophy with great clearness and method. In the preface to his “Physics,” for so his work is entitled, he makes no scruple to say, that “the abilities and accomplishments 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.” Clerselier, 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 marriage, against all the remonstrances of his family.

Rohault’s physics were written in French, but have been translated into Latin by Dr. John Clarke, with his brother Dr. Samuel Clarke’s notes, in which the Cartesian errors are corrected upon the Newtonian system. The fourth and best edition of “Rohaulti Physica,” by Clarke, is that of 1718, 8vo. He wrote also “Elémens de Mathématiques,” a “Traité de Méchanique,” and “Entretiens sur ]a Philosophic:” but these dialogues are founded and carried on upon the principles of the Cartesian philosophy, which has now no 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 and learned man, and an able philosopher.

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. Trigonometry. 3. Practical Geometry. 4. Fortification. 5. Mechanics. 6. Perspective. 7. Spherical Trigonometry. 8. Arithmetic. ¹