170 EXPERIMENTS ON VAPOUR. 
It is satisfactory to me to find that my results 
on steam from water, and on the vapour of al- 
cohol and ether agree very nearly with those of 
Gay Lussac, and this encourages the hope that 
those which I have obtained from pyroxilic spi- 
rit and acetic acid will be found to be near ap- 
proximations to the truth. In many of the 
combustible gases and vapours it would seem 
the atomic volumes are much the same as those 
of hydrogen. If this should be found true, it 
may lead usin many cases, to learn the atomic 
constitutions of compound elastic fluids from 
knowing the specific gravities of such fluids. 
