SODA. 319 SODIUM. the Acker process. The former has been under development at Aussig. The broad features of the method are illustrated in Fig. 2. In this dia- gram, a repi'csents the anode, h the solution of t i J/4
- ^~M
IJ-e ■s-^ b- / Fig. 2. DIAGRAMMATIC SKETCH OF THE GRAVITY CELL. BELL TYPE OP common brine which forms the electrolyte, d the bell, and c the cathodes; e is the pipe through which fresh brine is supplied and <; serves to cany away the chlorine gas. The caustic alkali solution overflows through the pipe f. A cur- rent efficiency of from 85 to 90 per cent, is claimed and the strength of the alkali solution varies between 100 and 150 grams of caustic soda per liter. Fig. 3. CEOSB-SECTION OF THE ACKER ELECTKOLVTIC FCRNACE FOE ALKALI. In the Acker fusion process, which is employed at Niagara Falls. X. Y.. the electrolyte consists of fused salt and the cathode of molten lead ; a diagrammatic sketch of the cell is shown in Fig. 3. K represents the connections between the bus bar and the anodes G. V the cell walls, 11 the upper level of the fused salt electrolyte, which overlies the molten lead cathode 1. A steam jet at the side of the cell circulates the molten lead cathode, and the decomposition of the lead-so- dium alloy produced is accomplished in a sepa- rate vessel. SODA WATEB. See Aerated Waters. SODEN, zo'dcn, Hermann, Baron (1852—). A lierman Protestant theologian, born in Cincin- nati, Ohio. He was educated at Esslingen, Urach. and Tiibingen, and was a vicar in various places from 1875 to 1880. From 1880 to 1882 he was a pastor in Dresden, then in Chemnitz (1882- 86), and in 1887 he took charge of the Jea-usa- lemskirche in Berlin. In 1803 he was appointed professor of theology in the University of Berlin. His publications include: PhUippcrhricf (1889) ; ll'ds thut (lie ecangelische Kirclicf (3eds., 1895) ; and I'aliistina und seine Oeschichte (1899). He also contributed vol. iii. to the Handkommcntar zum Xcucn Testament (1890), of which he was one of the editors. SODERHAMN, se'der-hiimn'. A seaport of Sweden on a small inlet of the Gulf of Bothnia, 135 miles north of Stockholm (Map: Sweden, GO). It has flour and saw mills, iron works, breweries and woodpulp factories, and exports timber, iron, and woodpulp to the value of nearly ,$5,000,000 annually. Its harbor has recently been enlarged and improved, and is entered each vear bv vessels aggregating about 300.000 tons. Population, in 1901, 11,258. SODERTELJE,. se'der-tel'yc. A town of the Llin of Stockholm, Sweden, 15 miles southwest of the city of Stockholm, of which it is practically a suburb (Map: Sweden, G 7). The town is on the Sodertelje Canal, which connects Lake Millar with the Baltic. It is a noted sum- mer resort, with mineral springs. There are machine shops, match factories, and spinning and weaving mills. Population, in 1900. 8207. SODIUM (Neo-Lat., from It. soda, soda, saltwort, glasswort). A metallic element iso- lated by Sir Humphry Davy in 1807. (See Potassium; Chemistry.) Compounds of sodium occur distributed in large cpiantities, especially sodium chloride, which is found in nature as halite or rock salt, and in solution in sea and other natural waters. Sodium also occurs in the form of nitrate (soda nitre, or Chile saltpetre), which is found almndant- ly in superficial deposits in the rainless dis- tricts of the Pacific coasts of Chile. Peru, and Bolivia; as the sulphate (Glauber's salt) or mirabilite; as the carbonate; and in numer- erous minerals of more complex composition, such as cryolite, the various feldspars, in- cluding albite, labradorite, oligoclase. and the zeolites. Sea plants, as well as animal or- ganisms, likewise contain sodium salts. The preparation of the metal itself may be accom- plished by decomposing sodium hydroxide by electrolysis. It was first prepared on a large scale by Sainte-Claire Deville. who reduced sodium carbonate with coal and chalk at a white heat, and collected the resulting metallic sodium under coal oil in suitable condensers. A commercial process now extensively employed was
