STEARINE AND STEARIC ACID IN WAX. 
215 
on the filter is pressed between two porous tiles till nearly- 
dry; it is then carefully transferred into a porcelain dish, and 
boiled with I drm.earbonate of soda and 6 drms. of distilled 
water, stirring the whole time, until some carbonate of soda 
begins to form on the bottom of the dish ; 1 oz. of alcohol 
of 0.80 is added to the warm mass, and the mixture stirred 
gradually, adding some ounces of alcohol of 0.50^ until the 
insoluble portion is converted into fine powder. When it 
has become perfectly cold, it is poured upon a filter, and 
edulcorated with alcohol of 0.50, until acetate of lead no 
longer produces any opacity j the whole is then evaporated 
to- 1 oz. The residue is filtered when cold, and washed 
with weak spirit. The liquid which passes is well shaken 
in a phial with 2 to 4 per cent, of stearic acid or stearine, a 
considerable froth is formed, which persists from half an 
hour to an hour; with pure wax the frothing is very slight, 
and it soon disappears. To farther test the liquid, an excess 
of acetic acid is added to it; if the wax was pure, there is at 
the utmost only a faint opalescence; but if it contain stearine 
or stearic acid, a precipitate is formed, especially on shaking. 
If it is desired to determine the amount of these impurities, 
the liquid is not treated with acetic acid, but with acetate of 
lead, as long as a precipitate is formed, and the liquid then 
acidified with acetic acid. When the precipitate has sub- 
sided, it is collected on a weighed filter, and washed with 
distilled water until the liquid which passes through is no 
longer coloured by sulphuretted hydrogen. If the wax was 
pure, the quantity of the precipitate from 1 drm. only amounts 
from one-half to two-thirds of a grain; if it contained 10 per 
cent, stearine, it amounts to 2 to 2 h grs. The quantity of 
the precipitate is not constant, and it is far more easy to de- 
termine the stearic acid than the stearine, for with 5 per 
cent, of the former the precipitate amounts from 2 to 2| grs. 
M. Buchner states, in a note to the above paper, that he 
has convinced himself of the practicability of the above 
method. — Chem, Gaz.,from Buck. Rep. 
