charcoal and sulphur. Tonite No. 3[A] is composed as follows:--Gun-cotton,
19 per cent.; di-nitro-benzol, 13 per cent.; and barium nitrate, 68 per
cent. or similar proportions. It is a yellowish colour, and being slower
in its explosive action, is better adapted for blasting soft rock.

[Footnote A: Tonite No. 1 was patented by Messrs Trench, Faure, and
Mackie, and tonite Nos. 2 and 3 by Trench alone.]

Tonite is extensively used in torpedoes and for submarine blasting, also
for quarries, &c. Large quantities were used in the construction of the
Manchester Ship Canal. Among its advantages are, that the English railways
will take tonite on the same footing as gunpowder; it is a very dense
material; if wetted it can easily be dried in the sun; it very readily
explodes by the use of a proper detonator; while it burns very slowly and
without the least danger; the cartridges being waterproofed, it can be
employed in wet bore holes, and it can be tamped with water; and finally,
as it contains sufficient oxygen to oxidise the carbon, no carbonic oxide
(CO) gas is formed, i.e., its detonation is perfect. It is a very safe
explosive to use, being little susceptible to either blows or friction.

Not long ago, a committee, composed of Prof. P. Bedson, Drs Drummond and
Hume, Mr T. Bell, one of H.M. Inspectors of Coal Mines, and others, in
considering the problem whether the fumes produced by the combustion of
tonite were injurious to health, carried out a series of experiments in
coal mines for this purpose. The air at the "intake" was analysed, also
the air of the "return," and the smoky air in the vicinity of the shot
holes. The cartridge was surrounded by the flame-extinguishing mixture,
and packed in a brown paper bag. During the first experiment nineteen
shots were fired (= 6.29 lbs. tonite). The "return" air showed only a
trace of carbonic oxide gas (CO). At the second experiment thirteen shots