s86 Dr. Henry's Description of an Apparatus for the 
to the quantity of oxygen required for their saturation. The 
olefiant gas, therefore, burns with the greatest brilliancy ; 
carbureted hydrogen gas, though inferior, affords a dense and 
compact flame ; but the carbonic oxide and hydrogen gas are 
entirely unfit to be employed as the means of artificial illumi- 
nation. 
In the execution of a series of experiments on the compound 
combustible gases, which are described in the 11th volume 
of Mr. Nicholson's Philosophical Journal, I had reason to be 
dissatisfied with the above method of effecting their decom- 
position, and to distrust the results which were obtained. The 
products of the combustion of the same gas varied considerably 
in different experiments ; and, with respect to some, it was 
evident that the full proportion of their carbonaceous ingre- 
dient was not oxygenised, in consequence of the precipitation 
of charcoal in the act of detonation. The quantities, also, that 
can be submitted in this way to experiment, are extremely 
minute ; and the inflammation of highly combustible gases is 
attended, as I have more than once experienced, with consi- 
derable danger from the bursting of the glass tubes. It was 
desirable, therefore, to employ a process not liable to these 
objections ; and after many alterations of the apparatus, con- 
trived with this view, I at length fixed upon one, which I shall 
now proceed to describe. 
The principal parts of the apparatus, are two glass cylin- 
ders, or air receivers,* bb and o o, of which the larger one is 
intended to contain oxygen gas, and the smaller one, the in- 
flammable gas submitted to experiment. They are connected 
* I am indebted to Mr. H. Creighton, of Soho, not only for a drawing of 
the apparatus but for much valuable assisance in the performance cf the experiments. 
