4} will strike a crimson colour, due to the action
of the aniline sulphate upon the nitric acid liberated from the nitro-
glycerine.

[Footnote A: "Notes on the Analysis of Explosives," _Jour. Amer. Chem.
Soc._, 1901, 23 [8], 585-589.]

~Tonite.~--The analysis of this explosive is a comparatively easy matter,
and can be performed as follows:--Weigh out 10 grms., or a smaller
quantity, and boil with water in a beaker, decanting the liquid four or
five times, and filter. The aqueous solution will contain the nitrate of
barium. Then put the residue on the filter, and wash two or three times
with boiling water. Evaporate the filtrate to dryness in a platinum dish.
Dry and weigh. This equals the Ba(NO_{3})_{2}. If the sample is tonite No.
3, and contains di-nitro-benzol, treat first with ether to dissolve out
this substance. Filter into a dish, and evaporate off the ether, and weigh
the di-nitro-benzol, and afterwards treat residue with water as before.
The residue is dried and weighed, and equals the gun-cotton present. It
should then be treated with a solution of ether-alcohol in a conical
flask, allowed to stand some three hours, then filtered through a weighed
filter paper, dried at 40 deg. C., and weighed. This will give the gun-cotton,
and the difference between this last weight and the previous one will give
the collodion-cotton. A portion of the residue containing both the gun-
cotton and the soluble cotton can be tested in the nitrometer, and the
nitrogen determined.

~Cordite.~--This explosive consists of gun-cotton (with a little
collodion-cotton in it as impurity), nitro-glycerine, and vaseline--the
proportions being given as 30 per cent. nitro-glycerine, 65 per cent. gun-
cotton, and 5 per cent. vaseline. Its analysis is performed by a
modification of the method given for gelatines. Five grms. may be
dissolved in ether-alcohol in a conical flask, allowed to stand all night,
and then filtered through a linen filter. The residue is washed with a
little ether, pressed, and dried at 40 deg. C., and weighed. It equals the
gun-cotton. The solution contains the nitro-glycerine, soluble cotton, and
vaseline. The cotton is precipitated with chloroform, filtered off, dried,
and weighed. The two ether-alcohol solutions are mixed, and carefully
evaporated down in a platinum dish upon the water bath at a low
temperature. The residue is afterwards treated with strong 80 per cent.
acetic acid, which dissolves out any nitro-g