UN CHEMlSTltY. 
5 
Things being thus arranged, and every precaution to obtain 
accuracy observed, the charcoal in the furnace was lighted, and such 
a fire maintained in another furnace under the retort, as sufficed to 
keep the water therein contained, continually boiling, and thus to 
force the steam into the tube that passed through the burning char¬ 
coal. “ After the operation, we find,” says Lavoisier,—“nothing 
but a few atoms of ashes remaining in the tube, the 28 grains of 
charcoal having entirely disappeared.” 
The products of the experiment were two gases, of a nature totally 
different from one another. The charcoal, situated as it was,—that 
is—within the glass tube surrounded by fire, had decomposed the 
aqueous vapor which was conveyed through it; and uniting with one 
of the constituents of the vapor, passed into a receiver, and was found 
to consist of 144 cubical inches of carbonic acid gas, weighing 100 
grains. This heavy gas had before been proved to be composed of 
carbon and oxygen ; therefore, oxygen was found to be one of the 
constituents of water. 
The other gas was observed to take fire, “when in contact with the 
air, by the approach of a lighted body;”—it occupied 380 cubical 
inches, but weighing only thirteen and seven-tenths grains. This 
was found to be hydrogen gas, and therefore, it was determined that 
water was composed of oxygen and hydrogen. The water expended 
in steam was eighty-five and seven-tenths grains: it had been proved 
by preceding experiments that, carbonic acid contained seventy-two 
grains of oxygen in every one hundred grains ; therefore, as the car¬ 
bonic acid gas produced (being one hundred grains), had taken 
seventy-two grains from the water,—and as the hydrogen gas 
weighed thirteen and seven-tenths grains, the eighty-five and seven- 
tenths grains of water evaporated from the retort were accounted for, 
and the important chemical fact established that eighty-five and 
seven-tenths grains of water “are composed of seventy-two grains of 
oxygen, combined with thirteen and seven-tenths grains of a gas 
susceptible of combustion.” This gas was subsequently named 
hydrogen gas, for the reason assigned in the introductory article, 
page 436, Vol. II. of the Horticultural Register. In the present 
state of widely diffused chemical knowledge, it will scarcely be need¬ 
ful for me to state that a variety of experiments by Lavoisier and 
his contemporaries, and by numberless chemists since his decease,— 
wherein many different substances were made to act upon water, 
have proved, beyond a doubt, that the analyses of the fluid have in¬ 
variably led to the same conclusion. It was also found that electricity 
•/ * 
excited by the common machine, was capable of separating the two 
