Caus, Or Canlx. I. Salomon De, a French engineer, born at or near Dieppe about 1570, died in Paris about 1630. Being a Protestant, he went to England about 1612. From 1614 to 1620 he resided at Heidelberg, as architect to the elector palatine Frederick V., and afterward returned to Paris. There is no historical ground for the story that he died insane in the hospital of Bicetre. He was one of the foremost physicists of his day; but his writings long remained almost unknown until Arago called attention to them. In his work, Les raisons des forces mouvantes(Frankfort, 1015; Paris, 1624; also in German under the title Von gewaltsamen Bewegungen, Frankfort, 1615), he gave a plan of an apparatus for raising water by the power of steam. Hence Arago considers him to have been the real inventor of the steam engine. Some have imagined that the marquis of Worcester derived from Caus the idea of the apparatus vaguely described in his "Century of Inventions" (1633), and " Exact and true Definition of the most stupendous Water-commanding Engine, invented by the Right Honorable Edward Somerset, Lord Marquis of Worcester." The other works of Caus are: La perspective, avec la raison des ombres et miroirs (London, 1012); Institution harmonique (Frankfort, 1015); Hortus Palatinus (Heidelberg, 1020); La pratique et demonstration des liorologues solaires (Paris, 1024). II. Isaac de, a relative (perhaps son) of the preceding, a native of Dieppe, was also an engineer and architect, and published among other things, Kouvelle invention de lever l'eau plus haut que sa source (London, 1044).