"The useful work consists partly in displacing the shattered masses. The
proportion of useful work obtainable has been variously estimated at from
14 to 33 per cent. of the theoretical maximum potential."

[Footnote A: C.N. Hake, "Notes on Explosives," _Jour. Soc. Chem. Ind._,
1889.]

Among the various forms of dynamite that are manufactured is carbo-
dynamite, the invention of Messrs Walter F. Reid and W.D. Borland. The
base is nitro-glycerine, and the absorbent is carbon in the form of burnt
cork. It is as cheap as ordinary dynamite, and has greater explosive
force, seeing that 90 per cent. of the mixture is pure nitro-glycerine,
and the absorbent itself is highly combustible. It is also claimed that if
this dynamite becomes wet, no exudation takes place.

Atlas powder is a dynamite, chiefly manufactured in America at the Repanno
Chemical Works, Philadelphia. It is a composition of nitro-glycerine,
wood-pulp, nitrate of soda, and carbonate of magnesia. This was the
explosive used in the outrages committed in London, by the so-called
"dynamiters." Different varieties contain from 20 to 75 per cent. of
nitro-glycerine.

The Rhenish dynamite, considerably used in the mines of Cornwall, is
composed of 70 parts of a solution of 2 to 3 per cent. of naphthalene in
nitro-glycerine, 3 parts of chalk, 7 parts of sulphate of barium, and 20
of kieselguhr.

Kieselguhr dynamites are being largely given up in favour of gelatine
explosives. The late Colonel Cundill, in his "Dictionary of Explosives,"
gives a list of about 125 kinds of dynamites. Many of these, however, are