1822.] Composition of the Alkaline Sulphurets. 355 
therefore, remains for us to examine, if a similar opinion has 
any probability. 
I have shown in a former memoir, that it is at least: extremely 
probable, that the double cyanuret of iron and potassium, the 
sulphocyanuret of potassium, &c. dissolve in water without 
decomposition, and are deposited in the state of crystals with- 
out the potassium being oxidated, and without the cyanogen 
or sulphuretted cyanogen combining with hydrogen to form 
acids. Ifthe compound of potassium with a combustible body 
acts thus, it is not impossible that another compound might be 
similarly circumstanced ; but it may be possible without actually 
occurring. 
Boiling water, when poured upon sulphuret of potassium, 
dissolves but a very small portion ofit ; the insoluble suffers no 
change either of colour or composition. I preserved sulphuret 
of calcium for several months in a stopped bottle, full of water, 
without this substance being decomposed. If then it was 
really decomposed by water, it would ‘appear that this decompo- 
sition ought to happen, even when the hydrosulphuret of lime 
formed is but slightly soluble in water, especially also as barium, 
calcium, manganese, X&c. decompose water, and evolve hydro- 
gen, although the oxide formed at the same time is not soluble. 
The solution of sulphuret of calcium obtained is colourless. 
When evaporated in vacuo over sulphuric acid, it is deposited in 
small white scaly crystals upon the sides of the vessel; these 
crystals when slightly heated part with the water, pass again to 
the state of sulphuret of calcium, in the same way as a salt 
with water of crystallization, or like the double cyanurets of 
iron with potassium, barytes, or lime. It is then at least as 
probable that the sulphuret of calcium dissolves in water with- 
out undergoing any change, and may combine with water of 
crystallization, as it is that this sulphuret should be decomposed 
by water into an hydrosulphuret. 
As to the sulphuret of potassium, it seems to act differently ; 
for this compound is deliquescent, and, therefore, nothing can 
be coneluded from it. In order to come near the truth, I fused 
the hydrate of potash in a small retort with a spirit lamp, and I 
added the sulphur in small portions ; on the introduction of each 
piece of sulphur, the matter boiled owing to heat excited by the 
combination ; aqueous vapour was formed; the salt assumed a 
yellowish colour, and separated a white caseous substance, 
which swam on the surface of the liquid, and by ebullition, 
it was carried still higher on the side of the glass. The 
operation was discontinued, while there still remained hydrate of 
potash in great excess. The white matter which was separated 
was easily dissolved in water, and the solution was colourless ; it 
Was precipitated by muriate of barytes, but the precipitate was 
dissolved by muriatic acid, and in a short time the solution was 
rendered milky with sulphur, and sulphurous acid was given out.’ 
2A2 
