, resin, paraffin, and naphthalene. After detailing at length the
methods he employs, he concludes with the observation that the knowledge
of the use of acetic acid--in which nitro-glycerine dissolves--for the
determination of nitro-glycerine may be serviceable. Mr F.W. Smith[A]
gives the following indirect method of determining nitro-glycerine in
gelatine dynamite, &c. About 15 grms. of the sample are extracted with
chloroform in a Soxhlet apparatus, and the loss in weight determined. In a
second portion the moisture is determined. A third portion of about 2
grms. is macerated with ether in a small beaker, the ethereal extract
filtered, and the process of extraction repeated three or four times. The
united filtrates are allowed to evaporate spontaneously, and the residue
warmed gently on the water bath with 5 c.c. of ammonium sulphide solution,
and 10 c.c. of alcohol until the nitro-glycerine is decomposed, after
which about 250 c.c. of water and sufficient hydrochloric acid to render
the liquid strongly acid, are added, and the liquid filtered. The
precipitate is washed free from acid, and then washed through the filter
with strong alcohol and chloroform into a weighed platinum dish, which is
dried to constant weight at 50 deg. C. The contents of the dish are now
transferred to a silver crucible, and the sulphur determined. This amount
of sulphur, deducted from the weight of the contents of the platinum dish,
gives the quantity of substances soluble in chloroform with the exception
of the nitro-glycerine, moisture, and sulphur. The amount of the former
substances _plus_ the moisture and sulphur, deducted from the total loss
on extraction with chloroform, gives the quantity of nitro-glycerine.
Nitro-benzene may be detected, according to J. Marpurgo, in the following
manner:--In a porcelain basin are placed two drops of liquid phenol, three
drops of water, and a fragment of potash as large as a pea. The mixture is
boiled, and the aqueous solution to be tested then added. On prolonged
boiling nitro-benzene produces at the edge of the liquid a crimson ring,
which on the addition of a solution of bleaching powder turns emerald-
green. And nitro-glycerine in ether solution, by placing a few drops of
the suspected solution, together with a drop or two of aniline, upon a
watch-glass, evaporating off the ether, and then adding a drop of
concentrated sulphuric acid to the residue, when, if nitro-glycerine is
present, the H_{2}SO_{