158 
ON THE ASSAY OF COAL FOR CRUDE OIL, ETC. 
imistard. My sinapine tissne has been fairly tested for upwards of two years,, 
during which time I have received more than fifty testimonials from phy¬ 
sicians and surgeons of the highest standing in Great Britain and different 
parts of the world, and have never till now received other than the highest 
commendation of its action and utility. I may also state that there is no 
remedy in the Materia Medica but what has found some individual to vrliose 
idiosyncrasy it is inimical. In short, I am quite satisfied both with its name, 
which is no misrepresentation, and with its efficacy, which has stood the 
test so long, and has found but one to object to its action and its use. 
I am. Sir, yours res^oectfully,' 
Albert Cooper. 
Kensington, August 22,nd, 1866 . 
ON THE ASSAY OE COAL, ETC., EOB CRUDE PARAEEIN OIL, 
AND OE CRUDE OIL AND PETROLEUM EOR SPIRIT, PHO¬ 
TOGEN, LUBRICATING OIL, AND PARAEEIN. 
BY JOHN ATTEIELD, PH.D., F.C.S., 
niKECTOE or THE LABOEAXOET OE THE PHARMACEUTICAL SOCIETY OE GREAT BRITAIN. 
{Read before the British Association, Nottingham.') 
The enormous increase, during recent years, in the use of oils of mineral 
origin for lighting, lubricating, and other purposes, has so stimulated the de¬ 
mand for these liquids, that analytical chemists are often required to deter¬ 
mine the value of a specimen of coal, shale, lignite, etc., as a source of crude 
paraffin oil, or the value of a specimen of the oil itself, or of the allied sub¬ 
stance of natural origin termed petroleum. Hitherto there has not been 
published any detailed method of conducting these examinations. The 
author, therefore, having from time to time had occasion to make a large 
number of such assays, ventures to supply the deficiency. 
Eirst, with regard to the assay of coal and other carbonaceous matters for 
crude oil. The method of manufacturing crude oil on the large scale consists, 
as is well known, in simply heating the coaly matter in large retorts; oil, 
water, and gas then distil off, and are collected in suitable receivers, while 
coke remains in the retort. Now the object of the analyst in experimenting 
on small quantities of oil-yielding materials of unknown value must be to ac¬ 
curately imitate this process, while, at the same time, he provides for the 
collection of products of all possible variety of character. It has been stated 
that a good indication of the value of such materials may be obtained by 
placing ten or twenty grammes in a porcelain crucible, imbedding the latter 
in charcoal contained in a much larger common crucible, and heating the 
whole in an ordinary furnace for an hour or two. Yolatile matters then pass 
off, and coke, prevented from burning by the surrounding charcoal, remains 
in the inner crucible. When cold, the coke is weighed, and the difference 
between this and the original weight of coal used gives the proportion of vo¬ 
latile matters. The facility with which such an experiment may be made has 
led to its frequent performance; the result is that one may see in books, etc., 
devoted to this subject, long columns of figures showing the proportion of 
volatile to non-volatile matter in a large number of oil-yielding substances. 
Probably, however, but little confidence can be placed in such results. A 
very small percentage of volatile matter would, of course, at once indicate 
that the substance operated on was of no value as a source of oil. Under all 
other circumstances the experiment is of little or no value, for I have found 
