756 SELENE SELEUCUS I. the crown ; and in 1625, being then a member of parliament, he took part against the royal favorite, the duke of Buckingham, whom in the succeeding parliament he aided in impeach- ing. From 1629 to 1634 he was imprisoned in the tower on a charge of sedition. He had meanwhile produced a variety of works, inclu- ding his Marmora Arundeliana (1 628). In 1 635 appeared his Mare Clausum, in answer to the Mare Liberum of Grotius. In the long par- liament, to which he was elected in 1640 for the university of Oxford, he frequently sided with the king. He opposed the exclusion of the bishops from the house of peers, and also the condemnation of Strafford, although he was one of the members named to prepare the articles against him. Subsequently he was keeper of the records in the tower, and hav- ing subscribed the u Solemn League and Cove- nant," he was appointed in 1644 one of the 12 commoners chosen commissioners to the admiralty. When it became apparent that the struggle between the crown and the com- mons could have no peaceful issue, he gradu- ally withdrew from political life. He died at the house of the countess of Kent, to whom he is said to have been married. He is now best known by his "Table Talk," published in 1689 by Richard Milward, his amanuensis. A com- plete edition of his works, with a memoir by David Wilkins, appeared in 1726 (6 vols. fol.). SELENE. See LUNA. SELEMTE. See GYPSUM. SELENIUM, an elementary substance discov- ered by Berzelius in 1817 in the refuse of a sulphuric acid manufactory near Fahlun. It resembles sulphur in many of its physical, and tellurium in many of its chemical characteris- tics. It is always found in combination, its compounds with the metals being called sele- nides, and they are very rare, the least rare being the selenides of iron, copper, and silver. The symbol of selenium is Se ; its atomic weight, 79 - 5 ; its specific gravity when crys- tallized, 4'788 ; its observed vapor specific gravity at 2,588 F., 5-68. When heated as an amorphous powder to 212 it softens, and when raised a few degrees higher it melts, and on cooling forms a dark brown vitreous solid with a metallic lustre and a specific gravity varying from 4*3 to 4'8. Selenium has neither taste nor smell, and is a bad conductor of elec- tricity. It combines with hydrogen to form eeleniuretted hydrogen, which has an offensive odor. The gas is obtained by the action of sul- phuric acid on selenide of potassium or iron. Selenium forms with oxygen and water sele- nious acid, II s SeO s , and selenic acid, Il-iSeO*, which correspond in composition to sulphurous and sulphuric acids (see SULPHUR), and form salts called respectively selenites and seleniates. SELECCIA, the name of numerous ancient cities of Asia, situated in Assyria, Margiana, Syria, Mesopotamia, Cilicia, Pamphylia, Pisi- dia, Curia, and other countries. I. Stteida on the Tigris was founded by Seleucus I. of Syria, on the right bank of that river, near its junc- tion with the royal canal of Babylonia, and opposite the mouth of the Delas (now Diala) river, a little S. of the modern city of Bagdad. Commanding the plains of the Tigris and Eu- phrates, and the principal caravan roads of Assyria and Babylonia, and peopled by set- tlers from various countries of western Asia, it rapidly rose in wealth and splendor, eclipsing Babylon, until it was in its turn eclipsed by Ctesiphon, built by the Parthians on the op- posite bank. The later wars of the Romans against that people proved destructive to Se- leucia. It had more than half a million in- habitants in the 1st century, in the 2d was burned by Trajan and Lucius Aurelius Verus, and captured by Septimius Severus, and in the expedition of Julian against the Persians in the 4th century was found deserted. II. Stleida Pleria, a strong fortress of northern Syria, also founded by Seleucus I., was built at the foot of Mt. Pieria, on a rock overhang- ing the Mediterranean, a few miles N. of the mouth of the Orontes, and W. of Antioch, with which it was simultaneously founded, and of which it formed the seaport. It sur- rendered to Ptolemy III. of Egypt, was re- covered by Antiochus the Great, and in the later period of the Syrian kingdom became in- dependent. Under the Romans it rapidly de- cayed. Considerable ruins of its harbor, forti- fications, and necropolis are still to be seen. SKLKM I S L, Mrator, the founder of the Syrian monarchy, and of the dynasty of the Seleuci- dre, born about 858 B. C., assassinated at Ly- simachia in 280. He was the son of Antiochus, one of the generals of Philip of Macedon, and accompanied Alexander in his Asiatic expedi- tion. After the death of that monarch ho ad- hered to the fortunes of Perdiccas, but soon after headed his assassins at Pelusium (321). On the second division of the empire he re- ceived the satrapy of Babylonia, joined An- tigonus against Eumenes, and received from the form'er the government of Susiana. Anti- gonus very soon became jealous of his power, and planned his destruction. Seleucus escaped with about 50 horsemen, fled to Egypt, and formed a league with Ptolemy, Lysimachus, and Cassander against the common enemy. Seleucus regained possession of the government of Babylonia in 312, and from this year the Syrian monarchy is reckoned to commence. In 806 he assumed the title of king, and in 302 joined the new league formed by Ptolemy, Cassander, and Lysimachus against Antigo- nus. The war was ended by the victory of the allies at Ipsus in 301, when Antigonus was killed, and Seleucus obtained all the Asiatic territory conquered by the Greeks, with the exception of lower Syria and western Asia Minor. His empire, extending over about 1,000,000 sq. m., included parts of Cappado- cia and Phrygia, Armenia, upper Syria, Meso- potamia, Media, Assyria, Babylonia, Susiana, Persia, Parthia, Bactria, and the territory east-
