IV. TECHNICAL. 533 



2690. Salt Cake, or commercial sulphate of soda, containing 

 about 98 per cent, of real sulphate, made by decomposing common 

 salt with vitriol in an iron pan heated externally. When about 

 three fourths of the decomposition has been eifected, the charge is 

 pushed upon the bed of a " muffle " furnace, maintained at a bright 

 red heat till the decomposition is completed. The gaseous hydro- 

 chloric acid evolved during the process is conducted away through 

 pipes or flues to condensing towers, where, being absorbed by 

 water, it assumes the form of liquid acid. 



Sullivan fy Co., Lancashire. 



2691. Limestone, or native carbonate of lime from Derbyshire, 

 used in combination with slack or small coal for converting salt 

 cake or sulphate of soda into carbonate of soda. 



Sullivan Co., Lancashire. 



2692. Slack, or small coal from the Lancashire coalfield, used in 

 combination with limestone for converting salt cake or sulphate of 

 soda into carbonate of soda. 



Sullivan fy Co., Lancashire. 

 



2693. Black Ash, or, ball soda, containing about 24 per cent, of 

 soda, produced by fluxing together in a suitable furnace a mixture 

 of salt cake or sulphate of soda, limestone, and slack, by which 

 means the sulphate of soda is converted into carbonate of soda, 

 the carbonate of lime of the limestone into calcium sulphide, and 

 the slack into coke. Sullivan 3? Co., Lancashire. 



2694. Vat Liquor. A saturated solution of soda produced by 

 lixiviating " black ash " or " ball soda" with warm water in iron 

 tanks or vats ; when the solution is saturated it is run off into iron 

 pans to be boiled down, the calcium sulphide and unburnt coke 

 of the " black ash " being left behind in the vat as " tank '' or 

 " vat waste." Sullivan fy Co., Lancashire. 



2695. Salts, or crude carbonate of soda, obtained by boiling 

 down " vat liquors " in iron pans, heated either externally or by 

 passing the flame over the surface of the liquor in the pan. 



Sullivan $ Co., Lancashire. 



2696. Soda Ash, or finished carbonate of soda of commerce, 

 containing 58 5 per cent, of real alkali, produced by gradually 

 heating to redness in a reverberatory furnace " salts " or crude 

 carbonate of soda. Sullivan fy Co., Lancashire. 



2697. Salt, as used in the " Hargreaves" process. The salt is 

 placed in a moist state on drying floors, and when dried into 

 hard flat pieces is broken by machinery. 



Sullivan fy Co., Lancashire. 



