6?4< Mr. Davy’s Lecture on some new analytical Researches 
and acted upon by a small quantity of dense muriatic acid, 
diluted with an equal weight of water, when there were dis- 
engaged two cubical inches and a quarter of gas, which proved 
to he sulphuretted hydrogene. 
In another experiment, in which eight grains of potassium 
were heated in a retort of the capacity of twenty cubical inches, 
containing about nineteen cubical inches of sulphuretted hy- 
drogene, and a cubical inch of phosphuretted hydrogene, 
which was introduced for the purpose of absorbing the oxy- 
gene of the small quantity of common air admitted by the 
stop-cock, the inflammation took place as before, there was a 
similar precipitation of sulphur on the sides of the retort ; the 
mass formed in the place of the potassium was orange exter- 
nally, and of a dark gray colour internally, as in the last 
instance ; and when acted on by a little water holding muria- 
tic acid in solution, there were evolved from it five cubical 
inches only of sulphuretted hydrogene. 
Both these experiments concur in proving the existence of 
a principle in sulphuretted hydrogene, capable of destroying 
partially the inflammability of potassium, and of producing 
upon it all the effects of oxygene ; for had the potassium com- 
bined merely with pure combustible matter, it ought, as will 
be seen distinctly from what follows, to have evolved by the 
action of the acid, a volume of sulphuretted hydrogene, at least 
equal to that of the hydrogene, which an equal weight of un- 
combined potassium would have produced by its operation 
upon water. 
Sulphuretted hydrogene, as has been long known to che- 
mists, may be formed by heating sulphur strongly in hydro- 
gene gas. I heated four grains of sulphur in a glass retort, 
