455 
\ 
of carbon and hydrogen^ ^c. 
elements are the same, and in the same proportions as in 
olefiant gas, they are in a very different state of combination. 
The tension of the most volatile part of the condensed oil 
gas liquid, and indeed of the substance next beneath olefiant 
gas in elasticity existing in the mixture constituting oil gas, 
appears to be equal to about 4 atmospheres at the tempera- 
ture of 6o.® To ascertain this a tube was prepared, like the 
one delineated in the sketch. Fig. i, containing a mercurial 
gauge at a. c. and the extremities being open. It was then 
cooled to o® from a to 6, and in that state made the receiver 
into, which the first product from a portion of the original 
fluid was distilled. The part at h was then closed by a spirit 
lamp ; and having raised enough vapour to make it issue at 
Hote. The particular inclination of the parts of the tube one to another was 
given, that the fluid when required might be returned from atod without passing 
on to b. 
4 
