98 SALINES. [IV. 



"with water. The solution contains soda, and a salt of lime 

 remains. 



A. Soda-ash. — Practice has advanced far before theory in 

 this manufacture, for we knew but little of the theory of the 

 changes effected during the process until within the last few 

 years, although the manufacture has become so expanded that 

 England produces annually more than 100,000 tons of car- 

 bonate of soda. The process has been recently investigated, 

 with a practical object in view, by J. Brown (Phil. Mag. 3 

 ser. xxxiv.), and, for elucidating the theory, by Bodo linger 

 (Ann. Chem. Pharm. Ixi. Ixiii. Ixvii.) The following are two 

 analyses by linger, the first of the crude soda, that is, after 

 the mixture of salt-cake, limestone, and carbon have been 

 duly heated ; the second, of the residue, after the soluble salts 

 have been extracted. 



1. Crude Soda. 



Sulphate of soda 1.99 



Chloride of sodium 2.54 



Carbonate of soda 23.57 



Caustic soda 11.12 



Carbonate of lime 12.90 



Oxysulphide of calcium (3CaS,CaO) 34.76 



Sulphide of iron 2.45 



Silicate of magnesia 4.74 



Coal 1.59 



Sand 2.02 



Water 2.10 



99.78 

 2. Residue. 



Carbonate of lime 19.56 



Oxysulphide of calcium 32.80 



Sulphate of lime 3.69 



Hyposulphite of lime 4.12 



Hydrate of lime 4.02 



Bisulphide of calcium 4.67 



Sulphide of calcium 3.25 



