1822.] Composition of the Alkaline Sulphurets. 285 
vapour; this caused the excess of loss of the salt, and which 
did not reappear in the oxygen of the water. 
This experiment proves that the hepar contains sulphuret of 
potassium, seeing that if the combination of the sulphur with 
potash were possible, hydrogen gas certainly could not reduce 
this alkali in such a moderate degree of heat; but the loss suf- 
fered by the glass, throwing uncertainty upon the result of this 
experiment, I chose another method. [na similar apparatus, I 
reduced sulphate of potash by sulphuretted hydrogen, and I con- 
tinued the operation as long as water escaped with the gas; it oc- 
cupied three hours : some sulphur was deposited ; but as soon as 
water ceased to be formed, the sulphur no longer separated from 
‘the gas. I suffered the operation to continue a quarter of an 
hour after this period. 
One gramme of sulphate of potash was in this manner con- 
verted into 1-11 gramme of hepar. It was extremely fluid and 
black while hot; but on cooling, it became quite transparent, 
and of a deep red colour. It was readily dissolved by water ; 
the solution was bright and yellow. 
This solution was decomposed by muriatic acid, which preci- 
pitated a white powder without occasioning any evolution of gas. 
The fluid was heated to ebullition, and it then gave out a gas 
which was received in a solution of acetate of lead. After a 
moment’s ebullition, a current of atmospheric air was passed 
over the liquid to expel the last portions of sulphuretted hydro- 
gen. By these means a sulphuret of lead was obtained in the 
solution of the acetate, and which, after being washed and dried 
wn vacuo, weighed 1:407 gramme, containing 0-189 of sulphur; 
but if all the alkali of one gramme of‘sulphate of potash were 
reduced to potassium, the sulphuretted hydrogen evolved ought 
to contain .0°184 of sulphur. This difference could only arise 
from an error of observation. The sulphur precipitated by the 
muriatic acid being washed and dried, weighed 0:488 gramme, 
and by fusing it lost no weight. After this precipitation, the 
liquid, when mixed with muriate of barytes, gave no sulphate. 
One gramme of sulphate of potash contains 0°449 of potas- 
sium; supposing then that it 1s converted into sulphuret of 
potassium, the result of this is : 
ME Ao eee. Sat Oa ees . 44:9 
Sulphur (precipitated) ........... ».. 48°8 
Sulphur (in the sulphuretted hydrogen) 18-4 
112:1 
That is to say, exceeding the hepar dissolved by 0-011 gramme, 
and undoubtedly derived from some error in the analysis. The 
hepar obtained was, therefore, sulphuret of potassium ; but it is 
difficult to determine the degree of sulphuration. The sulphur- 
