4^5 
of carbon and hydrogeny &c, 
coal gas tar, as was expected, none could be detected in it, 
but the action of sulphuric acid is sufficient to show the ex- 
istence of some of these bodies in the coal gas itself. 
With respect to the probable uses of the fluid from com- 
pressed oil gas, it is evident in the first place, that being thus 
volatile, it will if introduced into gas which burns with a pale 
flame, give such quantity of vapour as to make it brightly 
illuminating ; and even the vapour of those portions which 
require temperatures of 170° 180° or higher for their ebulli- 
tion, is so dense as to be fully sufficient for this purpose in 
. small quantities. A taper was burnt out in a jar of common 
air over water; a portion of fluid boiling at 190° was thrown 
up into it, and agitated ; the mixture then burnt from a large 
aperture with the bright flame and appearance of oil gas, 
though of course many times the quantity that would have 
been required of oil gas for the same light was consumed : 
at the same time there was no mixture of blueness with the 
flame, whether it were large or small. Mr. Gordon has I 
understand proposed using it in this manner. 
The fluid is also an excellent solvent of caoutchouc, sur- 
passing every other substance in this quality. It has already 
been applied to this purpose. 
It will answer all the purposes to which the essential oils 
are applied as solvents, as in varnishes, &c. and in some 
cases where volatility is required, when rectified it will far 
surpass them. 
It is possible that, at some future time, when we better 
understand the minute changes which take place during the 
decomposition of oil, fat, and other substances by heat, and 
have more command of the process, that this substance, 
