64 



SODA-WATER 



e, deposited at the bottom of some saline lakes, in anhydrous octahedra, called 

 Thenardite, and also combined with sulphate of lime, as Glauberlte. 



It crystallises in oblique rhombic prisms which belong to the oblique prismatic 

 system. Its taste is saline, and bitterish. It is very efflorescent, and loses all its 

 ten equivalents of water by mere exposure to the atmosphere, at common temperatures. 



SODA, SULPHITE OF. NaO.SO 2 + 10HO (M - a 2 SO 3 + 1OH-O). This salt 

 is prepared largely for removing the last traces of chlorine from the bleached pulp 

 obtained in the manufacture of paper, and is hence called antichlore. 



It is prepared by passing sulphurous acid gas through a solution of carbonate of 

 soda, or on the large scale, by passing sulphurous acid gas, obtained by burning 

 sulphur in the air, over crystals of carbonate of soda. It crystallises in oblique 

 prisms, and is efflorescent, like the sulphate of soda, which it much resembles. Its 

 taste is sulphurous, and it possesses a slight alkaline reaction. 



A bisulphite of soda also exists, which forms irregular opaque crystals. 



SODA-WATER. A favourite beverage, formed by super-saturating a solution 

 of carbonate of soda with carbonic acid, produced under considerable pressure. 



The accompanying wood-engraving represents the improved arrangements of the 

 soda-water machine, as fixed for use, manufactured by Messrs. J. Tylor and Sons of 

 2 Newgate Street, London. 



To use this machine, it is necessary to fill the solution-pan o, with solution of soda, 

 about one ounce of bicarbonate of soda to 2 gallons of water. Usually this solution 

 .is made in a large cistern of slate, or wood lined with lead, from which it. is con- 

 veyed to the solution-pan, by means of a pipe and tap. The gasometer-tub (3) is filled 

 with water up to a constant level, above which the opening of the pipe coming from the 

 solution-pan is kept, while the other pipe, connected with the generator 2, is kept well 

 under the water. The bell of the gasometer being down, about 14 Ibs. of powdered 

 whiting is mixed with water, to the consistency of cream, and poured into the generator 

 (2) till it is about two-thirds full, when it is carefully closed. Next screw the leaden 

 acid bottle (1) on to the generator. Take off the small cap on the top of bottle, and put 

 in about a quart of diluted sulphuric acid half acid and half water and replace the 

 cap. This should be mixed in an open vessel. Muriatic or nitric acid may be used, if 

 sulphuric acid cannot be obtained. Swing the bottle slightly round, causing a little 

 acid to fall into the whiting and water, at the same time turning round the agitator, 

 the handle of which is on the top of the generator. As soon as the acid is mixed with 

 the whiting and water, gas is generated and passes up the pipe into the rising boll, 

 which it elevates by its pressure. The end of the other pipe is turned down below 

 the surface of the water, so that the gas passing through it may become cooled and 

 purified. The operation of making the gas should bo conducted slowly, the acid bottlo 

 being so moved that only a small quantity of acid falls into the generator at a time, 

 otherwise the gas would be generated too quickly, and throw the whiting and water 

 Into the pipe, and probably injure the generator. 



When the addition of acid and the turning of the agitator fails to produce more 

 gas, then the whiting is exhausted, and must bo removed. It is important that this 

 should be done after each time of using, before the whiting sets hard, or there will bo 

 a difficulty in getting it out, and a liability of straining or breaking the fan of the 

 .agitator. 



