JOSIAH 281 JOURDAN JOSIAH, King of Judah. He suc- ceeded his father, Amon, 641 B. c, at the age of eight years. He destroyed the idols and restored the worship of the true God, established virtuous magistrates for the administration of justice, and re- paired the temple. He also caused the law of Moses to be sought for and pre- served. He was wounded in a battle fought at Megiddo, against Necho, King of Egypt, and died in 610 B. c. JOTHAM, King of Judah, 758 B.C., son and successor of Uzziah, or Azariah. He succeeded his leprous father at the 8ge of 25 years, and reigned 16 years. JOTTJNS (yuh'tons), in Northern mythology, immense giants and magi- cians who had command over the powers of nature, and lived in dark caves in their kingdom of Jotunheim, from which they waged perpetual war against the ^Slsir, the bright gods of Valhalla. Originaly they represented the destructive forces in nature. JOTJFFROY, THEODORE SIMON (zho-frwa'), a French philosopher; born in Pontets, Doubs, France, July 17, 1796. He became a pupil of Cousin, at Paris, and from 1817 onward taught philosophy at various educational institutions in Paris, ni-health obliged him in 1838 to exchange his professorial chair for the post of librarian to the university. Jouffroy was not an original thinker, and founded no school. His merit is that he was the lucid interpreter of the teaching of the Scotch philosophers Reid and Dugald Stewart; he translated their works, adding critical introductions and notes. His own best books were : "Philo- sophical Miscellanies" (1833; new edi- tion 1883) ; "Course in Natural Law" (1835); "Course in i^Jsthetics" (1843; new edition 1883). For some time Jouffroy was a member of the Chamber of Deputies ; he was also well known as a journalist. He died in Paris, France, Feb. 4, 1842. JOUGS (jogz), an instrument of pun- ishment formerly used in Scotland, con- sisting of an iron collar which sur- rounded the neck of the criminal, and was fastened to a wall or tree by an iron chain. JOULE (named from the eminent English physicist, James P. Joule), in electricity, the unit of heat and work; the voltcoulomb, JOULE, JAMES PRESCOTT, an Eng- lish physicist; born in Salford, England, Dec. 24, 1818. He studied under Dalton the chemist, made researches into electro- magnetism, about 1840 turned his atten- tion to the subject of heat, and ultimately established the theory of the mechanical equivalent of heat. His published work consists mainly of papers read before the Royal Society, of which he was made a fellow in 1850, receiving its medal in 1852, and the Copley medal in 1870. He received in 1878 a civil list pension of $1,000 in recognition of his services to science. His most important achieve- ment was that of settling the mechanical equivalent of heat, which established that the quantity of heat capable of increas- ing the temperature of one pound of water 1° F. requires for its evolution the expenditure of mechanical energy repre- sented by the fall of 772 pounds through the space of one foot. He died in Sale, Oct. 11, 1889. See Joule's Law. JOULE'S LAW, a law which relates to the work done by an electric current in overcoming the resistance in the cir- cuit. It is substantially as follows: In any circuit carrying a current I, in am- peres, the heat energy developed, where R is the resistance of the portion of the current under consideration, equals I-R. This formula expresses, in watts, the ac- tivity of that portion of the current. Now the activity of one watt indicates the development of .24 calories of heat each second; consequently a complete ex- pression of the heat set free is H — I2X.24 calories, equal to IEX.24 calories a second. See Joule, J. P. JOURDAN", COMTE JEAN BAP- TISTE (zhoT-dong'), a French marshal; born in Limoges, France, April 29, 1762. He entered the army at 16, and, after seeing service in North America, rose under the republic to the rank of a Gen- eral of Division. In September, 1793, he obtained the command of the Army of the North, and on October 16, defeated the Austrians at Wattignies. In 1794 and 1795 he commanded the army of the Mouse and Sambre, and with it gained the victory at Fleurus, June 26, 1794, drove the Austrians back across the Rhine, took Luxemburg, and laid siege to Mainz. But on Oct. 11, 1795, he was de- feated at Hochst, and thus compelled to retreat over the Rhine. Crossing this river again in 1796, he penetrated as far as Bavaria, but was there beaten by the Archduke Charles at Amberg and Wiirz- burg; this discomfiture made him resign his command. In 1799 the Directory in- trusted him with the command of the Army of the Danube; but he was again defeated by the Archduke Charles at Ostrach and at Stockach. The First Consul employed him in 1800 in the reor- ganization and administration of Pied- mont; and on the establishment of thQ
