692 JOUFFKOY D'ARBANS JOULE by Damiron (1843). His Cours de droit natu- rel has been translated into English under the title of "An Introduction to Ethics," by W. H. Ohanning, and a selection from his essays un- der that of "Philosophical Miscellanies," by G. Ripley, in Ripley's " Specimens of Foreign Literature" (Boston, 1838-'40). .101 11 UOV D'ARBAAS, Claude Francois, mar- quis de, a French mechanician, born about 1751, died in Paris in 1832. The idea of steam- boats occurred to him first in 1775, on occasion of his examining a fire engine ; but he failed in the experiment which he made with a small propeller on the river Doubs in the summer of 1776. Other experiments in 1780 and 1783 on the same river and on the Saone at Lyons were less unsatisfactory, though far from suc- cessful ; and the government, after referring the matter to the academy, declined (1784) to grant him a patent, whereupon he went to England. He did not return to France until the consulate, when he became acquainted with Fulton. In 1816 he received permission to form a company, and the count of Artois allowed him to give his name of Charles Phi- lippe to the first steamer, which was launched on the Seine Aug. 20. But the enterprise, as well as that of a rival company, ended dis- astrously, and the marquis retired after the July revolution to the Invalides, where he died of the cholera. He wrote Memoires sur les pompes dfeu for the academy, and published in 1816 Les ttateaux-d-vapeur. His claim to the .discovery of steam navigation was acknowl- edged by Arago, and in 1840 by the French academy ; and Fulton spoke highly of his in- vention. His son AOHILLE, marquis de, born about 1790, was an ardent legitimist politician and writer, but after the revolution of 1830 devoted himself to the perfecting of steamboats, invented an unsuccessful system of railway propulsion, and published several works on history, inventions, &c. JOULE, James Preseott, an English natural philosopher, born at Salford, Dec. 24, 1818. At the age of 15 he became the pupil of Dr. John Dalton, the author of the atomic theory, who trained him in the art of physical experimenta- tion and the philosophy of chemistry, and taught him mathematics. His first scientific paper was upon the construction of electro-magnetic engines ; but on account of the difficulties in the way, the chief of which is the rapid decrease of attraction accompanying increase of distance between magnets, he soon relinquished the de- sign of producing a practical motor. In 1841 he gave a lecture in the royal Victoria gallery at Manchester on the results of his experiments on a new class of magnetic forces, which em- braced a statement of what had been done by Jacobi of St. Petersburg and himself in apply- ing magnetism as a motive power. Continu- ing the investigation in connection with Mr. Scoresby, Joule arrived at the result that a grain of coal consumed by a steam engine will raise 143 Ibs. one foot in height, while a grain of zinc consumed in a voltaic battery can only raise, theoretically, a weight of 80 Ibs. through the same distance ; and that the cost of power by electro-magnetism is about 25 times great- er than that of steam. His communication to the royal society " On the Change of Tempera- ture produced by the Rarefaction and Conden- sation of Air" led Prof. Thomson of Glas- gow to unite with him in investigating the thermal effects of fluids in motion. The first of the series of papers on this subject was read before the royal society in June, 1853, the last in June, 1862 ; and they were all published in the " Philosophical Transactions." He also published, in connection with Dr. Lyon Play- fair, an account of investigations into the volumes occupied by bodies when in a solid state, and when dissolved in water ; a subject having many important relations to molecular physics. His inventive talent was early dis- played in the construction of galvanometers, the use of which was so constantly required in his electro-magnetic investigations. In 1863 he described to the Manchester society a new and sensitive thermometer, with which he was en- abled to detect heat in the moon's rays. The principal subject to which he has devoted him- self, however, is that of heat in its relation to mechanical power. His labors in this direc- tion commenced about the year 1840, when he communicated to the royal society the dis- covery of a principle in the development of heat by voltaic action, in which he established certain relations between heat and chemical affinity. The experiments of Count Rumford in 1796-'8 had exposed the fallacy of the calo- ric or material theory of heat, and had very nearly established the mechanical equivalent of heat, and Prof. Mayer of Heilbronn had announced his belief that the heat evolved in compressing a gas was exactly equal to the compressing force; but these views required for their complete establishment the demon- stration by experiment. Placing water in a vessel made for the purpose, Joule agitated it by paddles driven by a measured force, and de- termined both the amount of heat produced by stirring the liquid, and the amount of labor ex- pended. He also measured the amount of heat produced by revolving cast-iron wheels against one another. He varied the experiments by for- cing water through capillary tubes, and calcula- ting the heat generated by the friction produced. He employed other liquids in place of water, such as oil and mercury, and although he found a different degree of sensible heat evolved with the same force expended upon different fluids, still he found that it was exactly in the inverse proportion of the fluid's specific heat, thus add- ing another proof of the correctness of his opinions, and of his methods of experimenting. By numerous trials he found that the quantity of heat required to raise one pound of water one degree F. in temperature is precisely com- Eetent to raise 772 pounds avoirdupois one jot in height, or in other words, is equal to
