by the reciprocal Action of Sulphur and Charcoal. 409 
My first care was to procure a sufficient quantity of this li- 
quor. The process of Messrs. Clement and Desormes requiring 
the use ‘of porcelain tubes, and consequently an expensive ap- 
paratus, I endeavoured to procure a sulphuret which should 
easily give out its sulphur, and I thought that none would better 
serve, the purpose than the sulphuret of iron at the maximum: 
viz. iron pyrites. M. Lampadius only sueceeded once in ob- 
taining it by this process, but the cause must have been owing 
to something which I proposed to discover. 
Operation 1, I took one kilogramme of pyrites from the 
Pas-de-Calais, clean and pure, and 50! gramines of common 
charcoal, light, brilliant and sonorous. These two substances, 
when reduced to a very fine powder and passed through a hair 
sieve, were perfectly mixed, and intreduced into a stone retort. 
To the neck of the latter was. fitted a lengthening tube entering 
a bell-glass with three necks (fuludures): one of them entered 
a very dry flask, and the other a bell-glass with two tubulures to 
-which was adapted a tube thrice curved, the extremity of which 
entered into an earthen pot full of water. The whole being 
perfectly well luted with fat luting, and the first joint covered 
with linen smeared with white of eggs and lime, a fire was 
kindled under the retort, which was made red-hot, and towards 
the end of the operation the dome of the furnace was sur- 
mounted by a funnel or vent. At first, before the retort became 
red, there was extricated a small quantity of a diaphanous li- 
quid which had all the appearance of water. Afterwards there 
came over a considerable quantity of gas. Several flasks of it 
were collected at various stages of the operation, care being 
taken always to use the same water contained in the earthen- 
ware jar, in order to fill the flasks. This extrication of gas 
lasted during the whole of the operation. The two bell-glasses 
were covered with cloths, which were wetted with cold water 
from time to time. .The liquor, which was at first diaphanous, 
became milky in about an hour. After four or five hours of 
heat carried the length of actual incandescence, the diseng gage- 
ment of the gas having stopped, and nothing more Passing over 
into the receiver, the operation was stopped, the earthen jar 
removed, the extremity of the tube well dried with joseph pa- 
per, the aperture was well closed with fat luting to prevent the 
access of air, and after the apparatus was cooled the matters 
which it contained were examined. 
Three products were obtained by this operation : 
1. Gases in a very great quantity, which were ascertained to 
be a mixture of sulphuretted hydrogen, part soluble and part 
insoluble in water, oxycarburetted hydrogen, carbonic acid and 
azote, in proportions variable according to the stage of the ope- 
ration, 2. A 
