10 DR TRAILL ON THE TORBANEHILL MINERAL. 
a. Yielded 27°5 residue, and 724 per cent. was dissipated. 
bee P24 ere ew SON > 
Cr ID Os a OAs peers ” 
One hundred grains of Bitumenite afforded by distillation 60°5 cubic inches 
of inflammable gas, which is equivalent to rather more than 274 cubic feet per 
ewt.; and this gas had a far greater illuminating power than the best coal gas I 
have ever examined. I considered it in this respect to approach nearer to oil gas 
than to common coal gas. I did not, however. determine the comparative illu- 
minating power by the best test, chlorine, but estimated its superiority by the eye. 
Besides this, the distillation afforded a considerable quantity of the chemical 
compound known by the name of Parafine, a substance now used to grease ma- 
chinery, and for other economical purposes; a product which I have not ob- 
tained from coal when distilled for gas. 
I am well aware that by a slow distillation with a moderate heat, Parajine 
may be procured from certain kinds of coal, from peat, from bitumens, and per- 
haps from every substance capable of yielding olefiant gas, or what has been 
termed Bicarburetted Hydrogene ; for their atomic constitution seems to be nearly 
similar =C4+H4, or some multiple of these. This substance has been manufac- 
tured in large quantities from Bitumenite by Mr Youne, as the specimen on the 
table will shew. 
By distillation, too, petroleum may be obtained from it, especially if the mi- 
neral be first allowed to imbibe as much water as it can absorb; and this pro- 
duct is more abundant, more than is yielded by any coal. The fixed residue of the 
combustion of Bitumenite consists chiefly of silex and alumina, with traces of 
lime and oxide of iron. 
Bitumenite occasionally contains casts of vegetable remains, especially of 
large Stigmarie. A very magnificent specimen of Stigmaria in Bitumenite, as 
thick as the human body, has been deposited by Dr Curistison in the University 
Museum. In examining the structure of thin slices by the microscope, I per- 
ceived where the organisms occurred some traces of vegetable structure; but in 
other portions of the mineral I was unable to perceive the least trace of organic 
structure. In several specimens, in the hands of Mr Sanperson the lapidary, [ 
was also unable to see real organic structure; but observed numerous globules of 
a pale yellowish matter, which I take to be bituminous particles disseminated 
among the opaque earthy ingredients. 
But even if such organic texture could be traced in every part of it, still this 
would not constitute it a coal; for organic structure is constantly seen, too, in 
mineral charcoal, in surtarbrandr, in peat, and in petrified wood; yet nobody 
would denominate these varieties of coal. 
