by the Combuftion of Hydrogen in Oxygen Gas. 153 
gen gas. The adopter is now to be kept cool by water, al- 
lowed to trickle down over it from the vefiel Q. 
- During the combuftion meafured quantities of the gafes 
are to be introduced into the proper funnels; and when it is 
wifhed to interrupt the procefs, the cock which admits ‘the 
hydrogen gas is to be quickly ftopped. As the veffels cool, 
the oxygen gas and aqueous vapour in the adopter will con- 
traét in bulk, and the water in the oxygen funnel will rife 
towards the brafs cap f. At this moment the cock muft be 
fhut to prevent the water from rifing higher. 
When the procefs is to be renew agi the oxygen funnel is 
to be charged with gas, and the cock to be opened. The 
hydrogen funnel is next to be charged ; the wire A e to be 
turned to its firft pofition, and the electric {park to be applied 
as before. Thus the combuftion may be carried on from 
day to day. That the electric fparks may {trike quickly: and 
vigoroufly, a communication fhould be made with a wire 
between the cufhion of the machine and the brafs cap m. 
As the trafes employed are not to bé confidered as: free 
from azotie gas, its prefence will at laft reduce the gas in the 
adopter to the ftandard of atmofpheric air. The flame will 
then become weaker, and muft be watched, that the cock of 
the hydrogen funnel may be {topped before the flame is ex- 
tinguifhed; otherwife fome of the hydrogen gas will pafs 
unaltered into the adopter, and be confounded with the azotic 
gas, from which it is not eafily feparable. 
' When the procefs is terminated, the quantity of aeepeinee 
gas remaining in its funnel is to. be noted from the grada- 
tions marked on the veflel, and to be deducted from the 
fum of the meafures of hydrogen gas employed. This funnel 
is then to be ferewed off. The oxygen funnel is to be treated 
in tliefame manner, proper attention being paid to the level 
of the water, and to the temperature and preflure of the air 
at the time. The adopter and ftoppers, being now in the 
ftate im which they were firft weighed, are now to be 
weighed, with the contained water, to determine its weig 
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