Page:The New International Encyclopædia 1st ed. v. 18.djvu/371

* SOCRATES. 317 SODA. spiration from partial aspects of his character. The Socrates who wore one garment summer and winter, wallied barefoot on the snow, and exclaimed at the fair: "How many things there are that I do not need," became tlirou^li Antis- thenes the author of the Cynic way of life and the Stoic philosophy. The Socrates who was all things to all men, and outdrank Aristophanes at Agathon's banquet, was the model of Aristippus, the founder of the Cyrenaic (and Epicurean) philosophy of experience and pleasure. The ideal Socrates depicted in the Platonic Apology, Crito, Goryius, and Phwdo became, in the decay of the old religions, the chief religious type of the ancient world, and to such moralists as Epicte- tus, Seneca, Dio Chrysostomus. and Marcus Au- relius the very embodiment and guide of the higher life. The best authority accessible to the Englisli reader is Zeller's Socrates and the Socratic Schools (Eng. trans., 1877). .Joel's Der cchte und der Xe}ioi>hoiitische Socrates (Berlin, 1901) is an ingenious attempt to extract the 'real Socrates' frcjm Xenophon's Jlcinorahilia. SOCRATES, Pri.so>- of. The name popularly given to three chamliers hewn in the face of the hill of Philopappus at Athens. The chambers are of small dimensions, and one of them is connected with a vaulted rotunda, the circular opening of which was originally closed by slabs. The ar- rangement in general is similar to that of the so- called Treasury of Athens at Jlycenoe. SODA (It. soda, soda, saltwort, glasswort, con- tracted from solida, fem. of snlido. from Lat. solidus, hard, solid ; connected with OLat. solltis, Gk. 6'Xo5, holes, Skt. sarra, whole, entire), or SoDifM Carbonate, Ka-CO,. A white solid sub- stance having a strong alkaline reaction and crys- tallizing with ten molecules of water, Na.C03+ lOHnO. In commerce it appears both with and without water. Crystallized, hydrated sodium carbonate, also called 'sal soda,' is the common washing-soda ; sodium bi-carbonate. or 'acid' so- dium carbonate. XaHCO.. is the common cooking- soda, an important constituent of all baking pow- ders. The dry carbonate. XaX'O,, is used in enor- mous quantities in the manufacture of glass and soap. Xative sodium carbonate, or 'sodium ses- quicarbonate,' Xa,CO,.2NaHCO.,+'2H.O. is found to some extent in all dry regions, notably in Hun- gary, Egv'pt, and the deserts of Africa, Asia, and Xorth and South America, but in no other country does it occur in greater quantities than in the region lying east of the Sierra Nevada Mountains. The mineral is known as troim. Formerly most of the sodium carbonate of com- merce was derived from the ashes of certain plants, chiefly barilla and kelp, but at the present time the quantity derived from all other sources is insignificant when compared with that manu- factured from common salt. Xatural soda, which is the residue obtained by the evaporation of natural alkaline waters without the aid of artificial heat, occurs as white incrustations on the alkali plains; the most im- portant deposits, however, are in the form of 'sinks' or lakes without outlet, in which the leachings and drainings of the alkali plains have been collected and concentrated. Tn the L'nited States the waters of three lakes only. Albert Lake in Oregon and Mono and Owens lakes in Cali- fornia, are estimated to contain more than 118,- 000.000 tons of sodium carbonate an<l nearly 30,- 000.000 tons of sodium bicarbonate. Owing to the great distance from large Eastern markets and the consequent high freight charges, this im- mense supply of raw material for the inamifae- ture of the various sodium salts has not entered into successful commercial competition with the brine deposits of the Eastern States. The pro- duction of soda ash (sodium carbonate), sal soda (liydrated), sodium carbonate, sodium bi-carbo- nate, and caustic soda (sodium hydrate), from 50 works in the United States during 1902. ag- gregated more than 500.000 t(ms. which involved in the manufacture approximately 1.000,000 tons of salt. The quantities and values of these sodium compounds produced in the United States during 1000, according to the Twelfth Census, are given in the subjoined table: Pounds Value Soda ash 781.306.000 126,498.000 138.71-.i.0OO 23;i.5r,G,000 $1,8.?9,668 875.243 1.332,765 3.170.280 Total 1,280,082,000 SIO.237,944 Mancfactuke or Sodium Carbonate. Sodium carbonate is manufactured commercially by sev- eral processes, of which only two are of impor- tance — the Leblanc process and the Solvay pro- cess, each named fi-om its respective inventor. The Lehlanc process consists of three stages: ( 1 ) The conversion of common salt (sodium chloride) into sodium sulphate by the action of sulphuric acid, accomplished by the aid of heat in a rever- beratory furnace. This stage is called the salt- cake process, 'salt cake' being the technical name applied to the sodium sulphate product. Two chemical reactions are involved in this stage, viz.: NaCl+NaHSO,=Na,SO.+HCl XaCl-|-H.SO,r=NaHSO.+HCl (2) The decomposition of the sodium sulphate, by means of calcium carbonate and coal, at a high temperature in a furnace, the result being a crude product known as 'black ash,' which con- sists of sodium carbonate, calcium sulphide, calcium oxide, calcium carbonate, and small quan- tities of other substances. The principal reac- tions taking place in this stage of the process may be expressed by the following chemical equa- tions: 5Xa„SO.+ 10C=.5Na,S+10CO. 5Xa=S-F7CaC03=5Na,CO,+.5CaS+2CaO-f2CO, (3) The extraction of the sodium carbonate by treating the black ash with water to dissolve the sodium salt, which yields a solution called 'tank liquor.' containing also sodium hydrate. The crystals of sodium carbonate are obtained ulti- mately by evaporation, and. when calcined, yield the dry sodium carbonate of commerce, technical- ly known as soda ash. The calcium sulphide re- maining undissolved in the residues is treated for its sulphur content, and the hydrochloric acid produced in the first stage of the Leblanc process is saved for use partly as such, partly for making bleaching powder. In this manner from first to last there is practically nothing wasted except the calcium. The transformation of the salt cake into black ash is generallv carried out in a reverberatory furnace (Fig. 1), called a 'black-ash' or 'balling