Mr. Henry's Experiments on Ammonia. 437 
ture of ammonia and atmospheric air, each previously dried 
by caustic potash and then electrified, be examined, the pro- 
duction of water is made sufficiently apparent on applying 
ether to the containing vessel. In subjecting ammonia, there- 
fore, to this test of the generation of water by electricity, the 
purity of the gas from atmospheric air should be carefully 
determined.* 
The products of the combustion of ammonia with oxygen 
vary essentially, according to the proportion of the gases 
which are employed. If the oxygen gas exceed considerably 
the ammonia (that is, if its volume be double or upwards) the 
ammonia entirely disappears ; and no gases remain, but a 
mixture of nitrogen with the redundant oxygen. The mo- 
ment the detonation is completed, a dense cloud appears, -f 
and soon afterwards settles into a white incrustation on the 
inner surface of the tube. The quantity of this substance, 
which is produced, is too minute for analysis ; but its charac- 
ters resemble those of nitrate of ammonia, the acid ingredient 
of which is probably generated by the action of oxygen on 
the nitrogen of one part of the volatile alkali. Accordingly, 
when the excess of oxygen is removed by sulphuret of lime, 
* The result of this experiment shews, moreover, that even supposing oxygen to 
be a constituent of ammonia, we are not to expect its evolution, in a separate form, 
by electricity ; since, when electrified with ammoniacal gas, oxygen gas is deprived 
of its elastic form, and its base is condensed into water, by union with nascent hy- 
drogen evolved from the alkali. 
f In some cases I have observed, that when the cloud does not occur immediately, 
it may be made to appear by agitating the quicksilver contained in the detonating 
tube. This is probably owing to the disengagement of some ammonia, which had 
lodged in the mercury. The fact confirms what I have already suggested, respecting 
the cause of the variable proportion of gases, evolved from ammonia by electricity. 
MOCCCIX. 3 L 
