Compounds of Nilrogen. 515 
into graduated tubes, filled with mercury, 
which had been heated in tie same tubes and 
still remained hot. To prevent any ammo- 
niacal gas from lodging beneath the surface 
of the quicksilver in the tube, the flame of a 
spirit lamp was passed slowly along the part 
containing mercury, a precaution which was 
shown not to have been unnecessary by the 
ascent of a few bubbles of gas. 
In four experiments, conducted with a 
degree of caution, to which I am not aware 
that any thing could have been added, the 
volume of the ammoniacal gas was fully 
doubled. inthe first, 44 measures became 
88 +; in the second, 157 became 320; in the 
third, 60 became 122; and inthe fourth, 120 
became 240. The evolved gases, carefully 
analyzed by combustion with oxygen, were 
found in each case to consist of 1 volume of 
nitrogen and 3 volumes of hydrogen. I re- 
peated, also, with the greatest attention, a pro- 
cess for analyzing ammonia, which, with va- 
rious other methods capable of being more 
quickly executed than that of electrical ana- 
lysis, I have described in the Philosophical 
Transactions for 1809. It consists in firing, 
by the electric spark, a mixture of the alkaline 
gas with nitrous oxide, the latter being em- 
ployed in rather less proportion than would 
