344 Mr. Graham on the Heat disengaged in Combinations. 
afterwards with a fall of 1°94 and 1°90 in two experiments. 
The cold upon solution of this salt appears to be the same 
before and after fusion. The result is,x— 
Fall on solution of HO, SO;+ KO,SO,;. 1°95. 
I was anxious to compare with this salt the anhydrous bi- 
sulphate of potash of M. Jacquelin, which is described as 
being capable of dissolving in water without decomposition. 
One equivalent of sulphate of potash was accordingly dissolved 
in two equivalents of oil of vitriol, with the aid of heat, and an 
abundant crop was obtained on cooling of a salt in small silky 
crystals. As these appeared to be the salt in question, an 
equivalent quantity, or 79°60 grains, was dissolved, and a fall 
observed of 1°90. The result not differing from that of the 
former salt, the preparation of the anhydrous salt was repeated. 
The spongy mass of thin prismatic crystals obtained in a second 
experiment was pressed, dissolved again in water, crystallized 
and pressed again. The salt was still in minute prisms. ‘The 
solution of 39°8 grains, half the equivalent quantity, was at- 
tended with a fall in two experiments of 0°91 and 0°-95; or, 
for a whole equivalent, 1°86. Of the same salt, before the 
second solution, half an equivalent produced a fall of tempe- 
rature of 0°-96; or, for the whole equivalent, 1°92. These re- 
sults are identical with those formerly obtained with the hy- 
drated bisulphate, if allowance be made for the smaller quan- 
tity of the salt employed, a circumstance which excited a doubt 
as to the composition of the prismatic salt. The product of 
the second crystallization was accordingly analysed; 19°30 
grains of it gave 32°34 grains of sulphate of barytes, equiva- 
lent to 11°12 sulphuric acid, or 57°59 per cent.; 22°53 grains 
of the crystals lost no weight at 150°, but lost 0:24 water, or 
1:02 per cent., by cautious fusion. The proportion of acid in 
the salt is greatly under that of an anhydrous bisulphate, 
namely 62°98 per cent., while it approaches sufficiently near 
that of the hydrated bisulphate, 58°74 per cent. ‘The process 
of M. Jacquelin has not therefore given an anhydrous bisul- 
phate of potash in my hands, and none of my experiments fa- 
vours the existence of sucha salt; the silky prismatic crystals 
which I obtained being nothing more than an unusual form 
of the sulphate of water and potash. 
2. Bisulphate of Soda.—An equivalent quantity, 75°27 grains, 
of one and the same specimen of this salt, dissolved in three 
experiments with a fall of 0°:40, 0°28 and 0°17. It did not 
dissolve so easily as the bisulphate of potash, possibly from 
partial decomposition and formation of a portion of neutral 
sulphate of soda, The same supposition will explain the want 
