SODA 484 SOFISM and leading them toward self-knowledge, a vast movement of intellect which pro- duced, first Platonism and the Aristotel- ian logic, and then all the systems, even conflicting ones, which rose into more or less importance during 10 successive cen- turies. By his religious spirit, his belief in God and in immortality, his aim to reunite religion and immortality, and his own noble and beautiful life, he exerted so strong and wholesome an influence that the historian of the Christian religion, Neander, does not hesitate to say that Socrates, like John the Baptist, was a forerunner of Christ. Our primary au- thorities for the life and teaching of Soc- rates are Xenophon's "Memorabilia and Apology of Socrates," and Plato's "Dia- logues," in which he forms the great central figure. SODA, the protoxide of the alkaline metal sodium. It may be procured in an anhydrous state by burning the metal in dry air or oxygen. It is of a white color, greedily abstracting water from the air, which cannot be expelled by heat. In this state it forms hydrate of soda, or caustic soda. It is so similar in its properties to hydrate of potash that it need not be fully described here. Carbonates of Soda. — There are three of these, the ordinary monocarbonate, or common washing soda, Na2C03, which in its crystalline form contains 10 equiva- lents of water; the sesquicarbonate, Na2 C0 3 +2NaHC0 3 +3Aq, which occurs in the mineral kingdom as trona and urao; and the bicarbonate, NaHCO'3, which is prepared by passing carbonic acid through a concentrated solution of the carbonate till saturation takes place. It is also pre- pared by exposing the crystallized mono- carbonate to the action of a current of carbonic acid; but in this method of mak- ing it only the outside portions of the con- verted crystals should be used, the inner parts being only partially changed. It is ground and dried at a very gentle heat, care being taken to avoid a high temper- ature, which would cause the formation of the sesquicarbonate. Bicarbonate of soda crystallizes in prisms. It occurs in commerce as a white crystalline powder, which is gradually converted into the ses- quicarbonate by exposure to the air. It is much used in medicine. The properties of the monocarbonate are described under manufacture of soda. SODIUM, the alkaline metal of which soda is the oxide. It was discovered in 1807 by Sir Humphry Davy. It occurs in large quantities in nature, chiefly in combination with chlorine, as sea salt. SODOM, one of the cities of the plain, and for some time the dwelling-place of Lot. Its crimes and vices (the nature of which is recalled in the word sodomy) were so enormous that God destroyed it by fire from heaven, with three neighbor- ing cities, Gomorrah, Zeboim, and Admah, which were as wicked as itself. SOEST, a town of the province of Westfalen, Prussia; 34 miles S. E. of Munster; was once a Hanse town, and one of the most important places in Ger- many, with a population of between 30,- 000 and 40,000, but has declined since the Thirty Years' War. Its city law was the model for that of many other cities, such as Hamburg, Liibeck, etc. The re- mains of its walls with their 36 towers are still to be seen. It has a great num- ber of old churches, of which seven are now in use, the cathedral being Catholic and the remaining six Protestant. Soest is the center of a rich agricultural dis- trict, and has chemical works and exten- sive breweries. Pop. about 20,000. SOFIA, or SOPHIA, capital of the kingdom of Bulgaria; lies in a fertile plain on the upper waters of the Isker, an affluent of the Danube, to the N. of the Vitsch Mountains, 75 miles N. W. of Phil- ippopolis. The seat of a Greek metropoli- tan and a Roman Catholic bishop, it has many mosques, minarets, Christian churches, synagogues, etc. Sofia is the converging point of several important trade routes (three from the Balkans), and carries on considerable manufactures of cloth, silk wares, leather, and tobacco. In the vicinity are celebrated hot springs, with a temperature of 48° C. Sofia occu- pies the site of old Sardica, which was built by Justinian. It was taken from the Byzantine emperor Basilius in 809 by the Bulgarians, who called it Triaditza, a name which gave place at the time of the Crusades to that of Stralitz or Ster- nitz. It fell to the Turks in 1382. Dur- ing the Russo-Turkish War of 1877-1878 the abandonment of Sofia became neces- sary as soon as a considerable Russian force had made its way S. of the Balkans, and the retreat was effected without loss. At the Congress of Berlin (July, 1878), the English plenipotentiaries strove to join the town and district of Sofia to the province of Eastern Rumelia, but they were eventually included in Bulgaria. On Oct. 25, 1878, Sofia became the seat of government of Bulgaria. Pop. about 105,000. SOFISM, or STJFISM, the mystical and pantheistic doctrines of the Sofis. They consider that God alone exists; that He is in all nature, and that all nature is in Him, the visible universe being an emana- tion from His essence. God is the real author of the deeds of men, and there is
