274 £> r * Henry on the action of finely divided platinum on 
to dilute an explosive mixture, are equally inefficient in pre- 
venting the mutual action of its ingredients. Ammonia may 
be added in ten times the volume of the explosive mixture, 
and muriatic acid gas in six times its volume, with no other 
effect than that of rendering the action of the sponge less 
speedy. 
VI. Mixtures of Carbonic Oxide and Carburetted Hydrogen 
with Oxygen. 
When mixtures of these gases are exposed to the sponge, 
the carburetted hydrogen seems to stand entirely neutral. 
The carbonic oxide is converted into carbonic acid, in the 
same gradual manner as if it had been mixed with oxygen 
only, and the carburetted hydrogen remains unaltered. 
VII. Mixtures of Hydrogen , Carburetted Hydrogen , and Car- 
bonic Oxide with Oxygen. 
In mixtures of these gases, it is of little consequence whe- 
ther the oxygen be sufficient for the hydrogen and carbonic 
oxide only, or be adequate to the saturation of all three. The 
circumstance, which has the greatest influence on the results 
of exposing such mixtures to the sponge, is the proportion j 
which the simple hydrogen bears to the other gases, and 
especially to the carbonic oxide ; for in order that there may 
be any immediate action, the former should exceed the latter 
in volume. In that case the hydrogen is converted into water, 
and the carbonic oxide into carbonic acid ; but the carburetted 
hydrogen, unless the excess of hydrogen be very consider- 
able, remains unaltered. If the proportion of hydrogen be 
so small, that no immediate action is excited by the sponge, 
