212 Progress of Foreign Science. 
Potassiay 55 x08) ovetis ys or 44.9 
Sulphur (precipitated) . . . - . . 58.1 
Sulphur (of the sulphuretted hydrogen) . 18.4 
121.4 
The liquor, precipitated by muriatic acid, contained here no 
trace of sulphuric acid. The sulphuret of potassium obtained 
approaches to KS® (although the combination resulting from 
the total decomposition of the sulphate of potash by the sulphu- 
ret of carbon ought to be as in the preceding experiment KS?°.) 
It ought therefore to have weighed 119, instead of 122. Thus 
the actual result exceeds the 8 atoms by the same quantity, 
that the preceding result exceeded 7 atoms. These experiments 
prove then in a peremptory manner, that the hepar obtained was 
sulphuret of potussium in different degrees of sulphuration, and 
that through the agency of the sulphur, a very feeble heat is suffi- 
cient to reduce, by hydrogen or carbon, potash into potassium. 
The glass had not been attacked in any one of these experiments. 
4.65 grains of pure lime (free from water and carbonic acid), 
were introduced into a weighed tube of porcelain, and exposed 
to a stream of sulphuretted hydrogen. As soon as all the at- 
mospheric air had been expelled, the tube was heated to redness, 
at the place where the lime was situated. Aqueous vapours 
appeared, which were condensed on muriate of lime. ‘The ope- 
ration was continued, as long as it could be perceived that 
water escaped along with the gas; the tube was then suffered 
to cool, at the same time that the stream of sulphuretted hydro- 
gen was passed throughit, 1.57 grains of water were obtained ; 
and there remained in the tube 6.41 grains. These are, within 
a mere trifle, the weights which ought to result from the trans- 
formation of the lime into a sulphuret of calcium, and from the 
combination of the oxygen of the lime with the hydrogen of the 
gas. The compound was dissolved in muriatic acid, with dis- 
engagement of sulphuretted hydrogen gas; and muriate of 
barytes poured into the solution produced in it no precipitate. 
These experiments made with an alkaline earth, and an alkali, 
prove then in a decisive manner, that the compounds hitherto 
regarded as alkaline or earthy sulphurets, are combinations of 
sulphur with the metallic radical of the alkali or the earth. 
Since hydrogen reduces sulphate of potash, with the produc- 
tion of water which evaporates, it is clear that at an elevated 
temperature, sulphur may also reduce the potash into sulphuret 
of potassium, and that there ought to be formed at the same 
time, sulphate of potash; which fully confirms the opinion of 
M. Vauquelin, in regard to what happens when the sub-carbo- 
nate of potash is melted with sulphur. This celebrated chemist 
relates, in his experiments on the combinations of sulphur with 
the alkalis, that when the potash is united with the sulphur by 
fusion, there is formed a quantity of sulphuric acid, the oxygen 
