Passemant, Claude Simeon

, an able French optician, was born in 1702, and at first brought up to trade, which he partly relinquished for the study of natural philosophy and astronomy, and being already known to his advantage by several members of the academy of sciences, he published a volume in 1738, 12mo, on the construction of a reflecting telescope from sixteen inches to six feet and a half, the latter producing the effect of a telescope 150 feet long; and some time after, he wrote “The Description and use of Telescopes, Microscopes,” &c. of his own invention. He also constructed an astronomical pendulum, crowned with a moving sphere, which was made to represent the revolutions of the planets, in a manner that exactly Corresponded with the astronomical tables. He presented | this machine to Lewis. XV. and it was formerly to be seen in the royal apartments at Versailles. He made a similar instrument for the Turkish emperor, which shewed the rising and setting of the sun and moon. He furnished the king and other great men in France with sets of instruments for making experiments in optics, and other branches of science. In 1765 he gave some plans for making canals, by means of which ships might come up to Paris; and his proposal is inserted in M. de la Lande’s work on ie Navigable Canals," published 1778; but he had not the satisfaction of seeing it accomplished, being carried off in twenty-four hours, by a lethargy, November 6, 1769. 1