164 Miscellaneous Intelligence. 
retort. The residue in the retort is not a sulphuret of manganese, 
but a protoxide of manganese mixed with a little sulphate of 
manganese, and sometimes a little sulphur—Ann. de Chim. 
xxiv. 275. 
13. Preparation of Sulphuretted Hydrogen.—The experimental 
researches of M. P. Berthier, into the production and composition 
of certain metallic sulphurets, have been referred to at length, 
vol. xy. p. 148. Since then another paper has appeared by the 
same chemist, and relating to the same subject, from which we 
extract the following matter. In the preparation of sulphuretted 
hydrogen, it is usual to act on sulphuret of iron by diluted 
sulphuric acid, or sulphuret of antimony by strong muriatic 
acid ; but, for various reasons, M. Berthier recommends the follow= 
ing compounds of sulphur as better. Powdered common iron 
pyrites is to be mixed with half its weight of dry carbonate of 
soda, and heated red-hot in a crucible; a fluid sulphuret of iron 
and sodium is obtained, which may be poured out ona stone to 
cool, and is then a homogeneous deep yellow mass, possessing a 
lamellar fracture. It absorbs much water, forming with it a black 
paste, which when acted on by sulphuric or muriatic acid instantly 
yields abundance of sulphuretted hydrogen; leaving a black sul- 
phuret of iron, which by the application of acid and heat, will yield 
a second portion of the gas. 
Peroxide of manganese mixed with sulphur or charcoal, and 
heated to bright redness, becomes a protoxide, which treated with 
sulphuric acid forms a sulphate. This sulphate powdered, mixed 
with one-sixth of powdered charcoal, and heated to whiteness in 
a closed crucible, yields a pulverulent sulphuret of manganese, 
which when acted on by a mixture of one part sulphuric acid, and 
one part water, gives abundance of sulphuretted hydrogen, and 
becomes sulphate of manganese again: one hundred parts of the 
sulphuret yields 384 parts of sulphuretted hydrogen. 
Of all the sulphurets that of calcium appears to be the most 
proper for this purpose. It produces abundance of the gas, a 
hundred parts producing 46.8 of sulphuretted hydrogen ; the resi- 
due on the action of muriatic acid is entirely soluble, and therefore 
admits of perfect and free action without the application of heat; 
and it may be obtained in the greatest abundance. Sulphate of 
lime is to be reduced to an impalpable powder, and then mixed 
with powdered charcoal in the proportion of 0.15 of the latter, if 
the sulphate be a hydrate, but if an hydrous 0.20 of charcoal will 
be necessary. The mixture is to be put into crucibles, and heated to 
whiteness for an hour or two in a wind furnace. The sulphuret 
does not act on the crucible, and is obtained in a pulverulent state. 
If the sulphuret be required in great quantity it may be prepared 
by mixing the sulphate of lime and charcoal with a sufficient quan- 
