277 
SALTS. 
Chap. III. 
in the form of a white powder. It was formerly deno 
minated alum saturated with its earth. 
This salt does not crystallize, but has always the form Properties. 
of a tasteless powder. It is insoluble in water, and not 
altered by exposure to the air. Heat has no effect upon 
it unless it be very violent, and in that case part of the 
acid is disengaged. 
Sulphuric acid converts it into alum. It is less ea 
sily decomposed by other bodies than alum. Several 
of the acids dissolve slowly its last dose of alumina, 
and convert it into alum. 
This salt has not hitherto been applied to any use. 
Alum is capable also, as Chaptal informs us, of combi 
ning with several other bases, and of forming many 
triple salts, which have never yet been examined with 
attention *, 
Sp. 15. Sulphat of Zirconia. 
THrs salt was first formed by Klaproth, but Vauque 
lin has described it with more precision. It is prépa 
red by dissolving zirconia in sulphuric acid, and evapo 
rating the solution to dryness. 
Properties. 
It is usually in the form of a white powder. It may, 
however, be obtained in small needleform crystals. It 
has no taste, and is insoluble in water. It is not alter 
ed by exposure to the air. 
It is very easily decomposed by heat : the acid rea 
dily flies off, and leaves the earth in a state of purity. 
This decomposition may be accomplished even by boil 
ing in water ; the earth precipitates, and the acid re 
mains in solution. 
* Ann. de Cbim. xxii. 293, 
S 3