POTASH. 
201 
ORDER III. POTASH. 
1. Sulphate of Potash. 3. Muriate of Potash. 
2. Carbonate of Potash. 4. Hydrobromate of Potash. 
5. Alum. 
SULPHATE OF POTASH. 
Potasse Sulfatee. Hauy. — Aphthalose. Beudant. 
This salt has been found in some mineral waters, and was formerly thought to be one of 
the ingredients of the Salina brine. It also occurs among the products of volcanoes. 
Fig. 23. 
Fig. 24. 
Fig. 25. 
p 
M 
m! 
Description. Colour white. 
Taste slightly bitter. It crys¬ 
tallizes from its solution in 
the form of the right rhombic 
prism, which is the primary. 
Fig. 23. M on M / 118° 8" 
(Beudant.) It also occurs in 
short six-sided prisms termi¬ 
nated by six-sided pyramids, 
Fig. 24 ; and in dodecahe¬ 
drons, Fig. 25. It does not 
contain water, and suffers no change on exposure to the air; decrepitates when heated, and 
enters into fusion at a red heat. 100 parts of water dissolve 8.3 of the salt at 32° Fahr., 
and 25 parts at 212° Fahr. Specific gravity 2.40. 
The solution of this salt causes a yellow precipitate when treated with chloride of plati¬ 
num, by which it may be distinguished from the sulphate of soda, and indeed from all the 
salts of that alkali. 
Composition. Sulphuric acid 45.95, potash 54.07 (Beudant.) Formula K0.S0 3 . This 
salt, as well as the bisulphate of potash, is procured in large quantities in the manufacture of 
t 
sulphuric and nitric acids, where nitrate of potash is employed. 
CARBONATE OF POTASH. 
This salt has been found in the water of certain springs, but only in very small quantities. 
It is introduced here chiefly for the purpose of directing the attention of future observers to 
ascertaining whether it exists in our waters. 
Carbonate of potash exists in the ashes of plants, and, mixed with small proportions of 
other salts, constitutes the Potash and Pearlash of commerce. Formula KO.CO. 
Min. — Part II. 26 
