SALTS SULPHATES. 325 



The crystals, 



Acid, 24.70 or 1 proportion =40 

 Soda, 19.75 1 " =32 



Water, 55.55 10 " =90 



100. 162 its equivalent number. 



6. DECOMPOSITION. 



(a.) By combustibles, especially charcoal ; the same as that of sul- 

 phate of potassa. Immense quantities are produced in making muri- 

 atic acid, and in other manufactures ; therefore its cheap and effectual 

 decomposition is an object of vast importance for the sake of the soda. 



(b.) Potassa will do it. but the price of labor forbids, although 

 soda is dearer than potash. 



(c.) Decomposed (via humida,) by no acid, but it dissolves readily 

 in the nitric, muriatic and sulphuric acids, producing cold. 4 parts 

 sulphuric acid with 5 of this salt produce 47 of cold ; 2 parts nitric 

 acid with 2 water and 3 of this, produce more cold than the last mix- 

 ture ; 5 muriatic, and 8 of this salt, form a considerably powerful 

 mixture. 



.) Baryta and strontia decompose it, taking its acid. 

 SES. It is the most common domestic cathartic, and is called salts; 

 dosel oz. perhaps more, often 1 J oz. Used also in small diluted doses, 

 as a diuretic and aperient. The effloresced salts must be given in half 

 the quantity. It is now used in the manufacture of glass, p. 280 (b.) 



BISULPHATE OF SODA. * ' 



Formed by adding sulphuric acid to a hot solution of sulphate of soda; 

 product, large rhomboidal crystals ; efflorescent, soluble in twice their 

 weight of water at 60 ; lose their excess of acid by heat. Henry* 



SULPHATE OF AMMONIA. 



1. HISTORY, NAME, &tc. Discovered by Glauber, who called 

 it secret sal ammoniac ; other names vitriolated ammoniac, vitriol- 

 ated volatile alkali, &c. Found in the vicinity of volcanos, and in 

 the waters of the Tuscan lakes ; also in the ashes and soot of pit 

 coal.* 



2. PREPARATION. By mingling sulphuric acid 88 parts, and 

 compact carbonate of ammonia 100 parts, to mutual saturation, or 

 by decomposing muriate of ammonia, by sulphuric acid. 



3. PROPERTIES. 



(a.) The crystals are long six sided prisms, crowned with six 

 sided pyramids ; sometimes in plates, silky fibres, or clusters of 

 needles. f 



(" 



u.. 



* It is not probable that the ammonia exists in the coal, but the nitrogen of the 

 air and the hydrogen of the coal form the ammonia ; the oxygen of the air, with the 

 sulphur of the coal, forms the sulphuric acid, and this is doubtless the origin of the 

 sulphate of ammonia in the soot and ashes. t Tour. Vol. Ill, p. 55. 



