152 REPORT—1845. 
trogen does not exercise any disturbing influence on the estimation of explo- 
sive mixtures of gases. 
The nature of the gases ascending through the various parts of an iron 
furnace is obviously dependent upon the nature of the fuel used in it. 
Coke, brown coal and wood yield a gas containing as combustible consti- 
tuents only carburetted hydrogen, carbonic oxide and hydrogen. The ana- 
lysis of such a mixture offers no difficulties, and the proportion of the gases 
may be easily calculated if we are acquainted with the volume occupied by 
the oxygen which disappears, and that of the carbonic acid produced, re- 
ferring them to the volume of gas employed. 
A mixture of gas consisting of 1 vol. H+1 vol. H,C+1 vol. CO =3 vol. 
requires for combustion ......... 3 vol.O+2 vol.O+2 vol. O =3 vol. 
and yields \....5).0,) Sacs02c-.0e002 | VOL'CO,+1 vol CO, =2 vol. 
If we call any given mixture of gas A, consisting of x hydrogen, y light 
carburetted hydrogen, and p carbonic oxide; and further call the oxygen 
necessary for the combustion B, and the carbonic acid produced C, we ob- 
tain the following equations :— 
e+y+p=A, 
4u+2y+ip=B, 
yt+tp=C; 
and out of these follow 
1. #wz=A—C. 
I2B—A 
g, = , 
y 3 
3. pes 
But the gas generated, when coal is used as fuel, may contain, in addition to 
the above gases, olefiant gas, gaseous hydrocarbons of various compositions, 
and sulphuretted hydrogen. The examination of such a complex mixture of 
gases offers rare difficulties, which may be overcome by estimating directly 
the sulphuretted hydrogen and the hydrocarbons differing in composition 
from light carburetted hydrogen. Sulphuretted hydrogen is easily enough 
determined, but for the estimation of hydrocarbons, not even an approximative 
method is known. It is quite true that they may be condensed by free chlorine 
in the dark ; but the necessity of making such experiments over water render 
the results wholly inexact. This method also gives a source of error, which 
becomes materially increased by the circumstance that the tension of the sub- 
stance containing chlorine formed by the condensation cannot be brought into 
the calculation. We have therefore tried to condense the gases in a proper 
apparatus by means of perchloride of antimony. In order to be sure of the 
applicability of this substance, it was necessary to be certain that this com- 
pound of chlorine kept back the desired hydrocarbon without acting upon 
the remaining constituents of the mixture. It may easily be proved that 
carbonic oxide, light carburetted hydrogen and hydrogen are left quite un- 
changed by it, for after streaming through the liquid contained in a Liebig’s 
potash apparatus, they are again obtained unaltered in quantity or in proper- 
ties. But it was not so simple to decide whether olefiant gas and the other 
hydrocarbons of unknown composition were separated in this way pure and 
capable of quantitative determination. We have endeavoured to decide this 
