1 5% 
Mr. Davy on a Combination 
gene in the gas is condensed to half its volume. Circumstances 
conformable to the laws of combination of gaseous fluids, so 
ably illustrated by M. Gay Lussac, and to the theory of 
definite proportions. 
I have stated on a former occasion, that approximations to 
the numbers representing the proportions in which oxygene 
and oxymuriatic gas combine, are found in 7.5 and 32.9. And 
this compound gas contains nearly these quantities.* 
The smell of the pure explosive gas somewhat resembles 
that of burnt sugar, mixed with the peculiar smell of oxymu- 
riatic gas. Water appeared to take up eight or ten times its 
volume ; but the experiment was made over mercury, which 
might occasion an error, though it did not seem to act on the 
fluid. The water became of a tint approaching to orange. 
When the explosive gas was detonated with hydrogene, 
equal to twice its volume, there was a great absorption, to 
more than i, and solution of muriatic acid was formed ; when 
the explosive gas was in excess, oxygene was always ex- 
pelled, a fact demonstrating the stronger attraction of hydro- 
gene for oxymuriatic gas than for oxygene. 
I have said that mercury has no action upon this gas in 
its purest form at common temperatures. Copper and anti- 
• In page 245 of the Phil. Trans, for i 3 io, I have mentioned that the specific 
gravity of oxymuriatic gas, is between 74 and 75 grains per 100 cubical inches. The 
gas that I weighed, was collected over water and procured from hyperoxymuriate of 
potash, and at that time I conceived, that this elastic fluid did not differ from the 
oxymuriatic gas from manganese, except in being purer. It probably contained some 
of the new gas ; for I find that the specific gravity of pure oxymuriatic gas from 
manganese, and muriatic acid is to that of common air, as 244 to 100 Taking this 
estimation, the specific gravity of the new gas will be about 238; and the number re- 
presenting the proportion in which oxymuriatic gas combines, from this estimation, 
will be rather higher than is stated above. 
