59 PATRICK, COUNT DARCY, Was descended from a noble and ancient Irish family, and was born on September the 18th, 1725, in the county of Galway. His parents who were attached to the exiled house of Stuart, sent him to Paris in 1789, where being put under the care of M. Clairault, at seventeen years of age, he gave a new solution of the problem of the curve of equal pressure in a resisting medium ; and this was fol lowed the year after by a determination of the curve de scribed by a heavy body, sliding by i t s own weight along a moveable plane, a t the same time that the pressure o f the body causes a n horizontal motion i n the plane. This problem had already been solved b y John Bernouilli and Clairault; but notwithstanding this circumstance, Cheva lier Darcy possessed a method peculiarly h i s own, and i t i s easy t o discover throughout the work, that degree o f striking originality which i s the leading character o f a l l his productions. The commencement o f the war, however, i n some mea sure took him off from the prosecution o f his studies, a s h e served a s captain o f the regiment o f Condi, during several campaigns i n Germany and Flanders. I n 1746, h e was appointed t o accompany the troops that were t o b e sent t o Scotland t o assist the Pretender, and had a narrow escape with his life, a s the vessel i n which h e sailed was captured b y the English, and Darcy, (whose life was for feited b y the laws o f his country, b y being taken i n arms against her,) was saved b y the humanity o f the English commander. During the course o f this war, and amidst a l l i t s bustles and dangers, h e found leisure t o contribute two memoirs t o the Academy. The first contained a general principle o f mechanics, that o f the preservation o f the rotatory motion. Daniel Bernouilli and Eulerhorm had discovered i t i n 1745; but i t i s highly improbable that their productions should have reached Mr. Darcy i n the midst o f his campaigns; his method i s different from theirs, but i t i s equally original, simple, elegant, and ingenious.
