sgo Dr. Henry's Description of an Apparatus for the 
languid by the admixture of carbonic acid with the gas in the 
receiver b, and by the diminished purity of the oxygen gas. 
If this be not attended to, a large proportion of the inflam- 
mable gas, towards the close of the process, makes its escape 
unaltered into the receiver b. In general I have found, that 
setting out with oxygen gas of equal purity, the more com- 
bustible the inflammable gas submitted to experiment, the 
more complete is its decomposition by slow combustion. 
The apparatus, therefore, is better adapted to the analysis of 
olefiant gas, of carbureted hydrogen gas, or of mixtures of 
these two, than of carbonic oxide, or any gas of which that 
oxide forms a large proportion. 
The inflammable gas, which has found its way into the re- 
ceiver b, is always present in too minute a quantity to compose, 
with the residuary oxygen, after the removal of the carbonic 
acid, a mixture capable of being inflamed by the electric spark. 
To ascertain its precise quantity, it is necessary to have re- 
course to another operation. After trying, eudiometrically, 
the quality of an aliquot part of the gas in the receiver b, let 
a similar aliquot part be deprived of its carbonic acid, and then 
mixed with a portion of pure hydrogen gas, not exceeding 
one third or one fourth the estimated bulk of the oxygen 
which it contains. Detonate the mixture, and observe the 
amount of the diminution after the explosion ; the products of 
the combustion ; and the quantity of oxygen gas consumed. 
After subtracting, from the total expenditure of oxygen, half 
the bulk of the added hydrogen gas, the remaining number 
shews how much oxygen has been absorbed by the combus- 
tible gas contained in the residue. By the rule of proportion, 
it may be determined, how much carbonic acid would have 
