of charcoal and hydrogen. 1 53 
doubt that by that agent the quantity of olefiant gas in any 
mixture of these gases may be accurately determined. We 
are not, however, acquainted with any chemical agent, either 
liquid or aeriform, which, from a mixture of hydrogen, car- 
buretted hydrogen, and carbonic oxide, is capable of separat- 
ing one of those gases, leaving the others in their original 
state and quantity.* The only method at present known of 
determining the composition of such a mixture is by firing it 
with oxygen gas, and, from the phenomena and results of 
the process, deducing the proportion of its ingredients. In 
drawing conclusions of this kind, it is necessary to have dis- 
tinctly in view the properties of those gases in their separate 
state. The following Table contains an abstract of their 
leading characters, which will be found very useful in such 
investigations. Though not strictly necessary, I have in- 
cluded olefiant gas, in order to render the Table more 
complete. 
Table. III. Exhibiting the characteristic properties of different 
combustible gases. 
Names of Gases. 
Sp. Gr. 
Air 1000 
loo Volumes 
require Oxygen. 
Total. 
Diminished by 
Firing. 
Carb. Acid 
produced. 
Olefiant Gas 
•970 
300 
400 
200“ 2" 
200 
Carburetted Hydrogen 
•556 
200 
300 
200=-f 
IOO 
Hydrogen Gas 
•069 
5 ° 
* 5 ° 
lSO = |. 
O 
Carbonic Oxide 
•972 
50 
150 
5 °=t 
IOO 
* I have not found that chlorine can be employed with any success in analyzing 
such mixtures ; for when placed in contact with two or more of those gases, and ex- 
posed to light, it does not act upon one exclusively, but upon all that compose the 
mixture. 
MDCCCXXI. 
X 
