PAPIN, DENIS, a celebrated French physicist, was b. at Blois, Aug, 22, 1647, and studied medicine, where, after receiving his degree, he practiced for some time as a He now became acquainted with Huygens, an incident which strengthened in him an original predilection for physical science; and from this time he devoted him self almost exclusively to his favorite study. Before Papin's time, the intense force which can be generated in water, air, etc., under the action of heat, was well known, but lie was one of the first to indicate the principal features of a machine by which this property-could be made of practical utility. He soon acquired a wide reputation, and on visiting England was received with open arms by the philosophers of that country, and became a member of the royal society in 1681. While in England, Papin and Boyle (q.v.) together repeated their experiments on the properties of air, etc.; but in 1687 Papin was called to the chair of mathematics in the university of Marburg in Hesse Cassel, the duties of which office he discharged with zeal and success for many years. He died at ,Marburg about 1714. The French academy of sciences, withholding from Papin the honor of " associate," enrolled him among its " correspondents"—a proceed ing on the part of the academy which has, with reason, excited the astonishment of F.
Arago. To Papin utitoubtedly, belong's the high honor of having first applied steam to produce motion by raising a piston; lie combined with this the simplest means of pro ducing a vacuum beneath the raised piston, viz., by condensation of aqueous vapor; he is also the inventor of the "safety-valve," an essential part of his "digester" (q.v.). By this latter machine Papin showed that liquids in a vacuum can be put in a state of ebulli tion at a much lower temperature than when freely exposed to the air. Papin's sagacity led him to many other discoveries; he discovered the principle of action of the siphon, improved the pneumatic machine of Otto de Guericke (q.v.), and took part against Leibnitz in the discussion containing "living" and " dead" forces. Unfortunately for science, Papin's numerous writings have not yet been collected, but many of them will be found in the Philosophical Transactions, Acta Eruditorum, and the Recueil de Diverses Pl2ces. He published two works, one being an explanation of the construction and uses of his " digester" (Lond. 1681), afterwards (1682) translated into French, and his experi ments entitled Nouvelles Experiences du Vide (Paris, 1674). It was not till nearly a .century after that the great value Of Papin's discoveries was perceived.