428 Experiments on the Gas, from Coal. 
The sums of the numbers thus theoretically 
obtained do not, it is true, exactly correspond 
with the experimental ones ; but they approach 
as nearly as, from the nature of the subject, 
can be expected, the greatest disagreement 
(that in the diminution by firing) not much 
exceeding th of the observed amount. 
In a similar manner we may explain the 
composition of the lighter and less combus- 
tible products, obtained at advanced periods 
of the distillation. For example, a portion 
of the last product of gas from cannel, dis- 
tilled in a glass retort, gave the following 
results. | | 
Measures Of g€S....0006. 20 
Mixed with oxygen......30—=28 pure oxygen-++2 azote. 
Total....... 50 
Fired eeeee COG ereeetereacares 22 
Washed with potash .,..18=14.7 oxygen-++3 .3 azote, 
13.3 oxygen spent. 
In this experiment, 1.3 more azote were 
found in the residuum, than can be traced to 
the oxygen employed. The combustible gas 
was, therefore, only 18% measures ; the car- 
bonic acid produced 4; the oxygen spent 
13.3; and the diminution by firing 28. The 
following supposed mixture will explain these 
facts. 
