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would be the next victim. A common soldier, finding him, saluted him as Emperor; others entered and bore him to the camp, where he was crowned, 41 A. D. In his reign the southern part of Britain was conquered and Mauritania made a Roman province. At home his rule was mild in the main, but he was influenced by his wives—he married four times—to commit some cruel acts. Two of his wives, Messa-lina and Agrippina, were among the worst Roman women of whom we know; and it was Agrippina who poisoned him in 54 A. D. to secure the throne for her son, Nero. Claudius built the famous Claudian aqueduct, and spent large sums in other improvements at Rome.
Clatisius (klou'ze-us), Rudolf Julius E., a distinguished German physicist, born at Koslin, in Pomerania, Jan. 2, 1822; died at Bonn, Aug. 24, 1888. He was educated at Berlin University, where he later became privat-docent and still later an instructor in the school of artillery. In 1855 he went to Zurich as professor of physics in the Polytechnic school; two years later he accepted the chair of physics in the University of Zurich. From 1869 until his death he was professor of physics in the University of Bonn.
His best work was done at Berlin, for it was here, between 1845 an(l I^5°> that he placed the science of thermodynamics upon a sound basis, building the entire structure upon the then recently discovered principle of the conservation of energy. In addition to this, his most important contributions are perhaps to the kinetic theory of gases and to the subject of radiant heat.
Clay is a term rather loosely applied to all sorts of earthy matter, which, when wet, becomes sticky or plastic. In this respect, clay is in contrast with sand. The stickiness depends in part on the size of the individual particles. The smaller they are, the more tenacious the clay. Clay originates from the decomposition of certain sorts of rock, especially those containing feldspar. In the popular use of the term no account is taken of the composition of clay, but silicate of alumina is a common constituent. Common clays also contain free silica, iron oxide, etc. When beds of clay are solidified by natural means, they constitute the rock known as shale. Flagstones are a variety of shale, and slate is a variety of rock formed from shale by great compression. Clay is widely used in the manufacture of brick, tile, pottery, etc. and in modeling. For the finer wares, such as china and porcelain, especially fine grades of clay (kaolin) are required. The value of the products manufactured from clay in the United States in 1898 exceeded $71,000,000. The leading states in the utilization of clay, in the order of their importance, are Ohio. Pennsylvania,
New Jersey, Illinois and New York. The value of the clay-products of these five states in 1898 was considerably more than half the total value of clay-products in the United States.
Clay, Cassius Marcellus, American statesman, abolitionist and United States minister to Russia, was born in Madison County, Ky., Oct. 19, 1810, and graduated from Yale in 1832. For a time he practiced law in Lexington, Ky., became a member of the state legislature and was an" active antislavery man and the editor of The True American, which brought him into collision for a time with the proslavery men of his state. He served in the Mexican War of 1846-47 and was taken prisoner. He afterward took part in the elections of Presidents Taylor and Lincoln, and in 1861 was appointed United States minister to Russia, in which capacity he served from 1863 to 1869. He died July 22, 1903. See the Memoirs, Writings and Speeches of Cassius M. Clay.
Clay, Henry, a noted American statesman and orator, was born in Hanover County, Virginia, April 12, 1777. His father died when he was five years old, but his mother, a woman of great goodness and force of character, well supplied his place in the boy's training. After a meager amount of schooling, Henry entered a Richmond law-office. Commencing to practice at Lexington, Kentucky, he soon became known as an able lawyer, his high personal gifts, winning address and frank, hearty manner helping him here, as they did all through lite, From the first he took an interest in public affairs, and after two years in the state legislature, was chosen United States senator to fill a vacancy. He at once became an advocate of the government's building roads, canals, etc., being known as a loose constructionist of the constitution, as it is called. His short term over, he went back to the Kentucky legislature. This was in the days of duels, and it is not strange that Clay should have fought two, one at this time in Kentucky and, later, one with John Randolph of Virginia, both growing out of politics. In 1809 ^e was chosen to fill a second vacancy in the senate. In this session he spoke in favor of protection to American manufactures against foreign traders. He also opposed the United States Bank, but later he changed his views in the matter, the only instance in which he ever changed his attitude on a political question. In 1811 he was elected a representative in Congress, and the day on which
HENRY CLAY
