Analysis of the compound inflammable Gases . go l 
Grains. 
A cubic foot, at a mean of the barometer and ther- 
mometer, - 333-5 
By combustion, it yields 817.3 grains of carbonic 
acid, the carbon in which may be estimated * at 233.7 
Grains of hydrogen in a cubic foot of coal gas 99.8 
But 99.8 grains of hydrogen are equivalent to the saturation 
of 554.9 grains of oxygen, with which they form 654.7 grains 
of water. Hence the oxygen consumed ought from calcula- 
tion to be 81 7.3 — 233.7 = 573- 6 + 554-9 =1128 
And the quantity actually consumed appears by 
experiment to be - - 1110.3 
Error 17.7 
The difference, in this example, between experiment and 
calculation is not greater, than, in such delicate processes, 
may always be expected. A part of the deficiency in the 
oxygen actually consumed may be ascribed, also, to a small 
portion of the inflammable gas being already in the state of 
carbonic oxide. 
Without repeating the particulars of a similar calculation 
made on gas of inferior quality, I shall annex a comparative 
statement of the specific gravities and composition of the good 
and inferior gases. 
Source of the Gas. 
Weight of a 
Cubic Foot. 
A Cubic Foot 
consists of 
Carbon. Hydr. 
Oxygen Gas 
consumed by 
a Cubic Foot. 
Gives 
( ^ , 
Carb.Acid Water 
j 
Newcastle coal 
Ditto, last product 
333 -5g r - 
ib9-3 
233-7! 99- 8 
in-5157- 8 
1 no. q 
560. 
817.3621 
40° 384.9 
* Assuming the carbon to be 28.6 grains in 100 grains of carbonic acid, as is 
satisfactorily proved by the experiments of Messrs. Allen and Pepys. 
