Nitro-toluol is used,
mixed with nitro-glycerine. This list, however, does not exhaust the
various substances that have been nitrated and proposed as explosives.
Even such unlikely substances as horse dung have been experimented with.
None of them are very much used, and very few of them are made upon the
manufacturing scale.

CHAPTER IV.

_DYNAMITE AND GELATINES._

Kieselguhr Dynamite--Classification of Dynamites--Properties and
Efficiency of Ordinary Dynamite--Other Forms of Dynamite--Gelatine and
Gelatine Dynamites, Suitable Gun-Cotton for, and Treatment of--Other
Materials used--Composition of Gelignite--Blasting Gelatine--Gelatine
Dynamite--Absorbing Materials--Wood Pulp--Potassium Nitrate, &c.--
Manufacture and Apparatus used, and Properties of Gelatine Dynamites--
Cordite--Composition and Manufacture.

~Dynamite.~--Dynamite consists of nitro-glycerine either absorbed by some
porous material, or mixed with some other substance or substances which
are either explosives or merely inert materials. Among the porous
substances used is kieselguhr, a silicious earth which consists chiefly of
the skeletons of various species of diatoms. This earth occurs in beds
chiefly in Hanover, Sweden, and Scotland. The best quality for the purpose
of manufacturing dynamite is that which contains the largest quantity of
the long tubular _bacillariae_, and less of the round and lancet-shaped
forms, such as _pleurosigmata_ and _diclyochae_, as the tube-shaped diatoms
absorb the nitro-glycerine better, and it becomes packed into the centre
of the silicious skeleton of the diatoms, the skeleton acting as a kind of
tamping, and increasing the intensity of the explosion.

Dynamites are classified by the late Colonel Cundill, R.A., in his
"Dictionary of Explosives" as follows:--

1. Dynamites with an inert base, acting merely as an absorbent.

2. Dynamites with an active base, i.e., an explosive base. No. 2 may be
again divided into three minor classes, which contain as base--

(_a._) Charcoal.

(_b._) Gunpowder or other nitrate, or chlorate mixture.

(_c._) Gun-cotton or other nitro compound (nitro-benzol, &c.).

The first of these, viz., charcoal, was one of the first absorbents for
nitro-glycerine ever used; the second is represented by the well-known
Atlas powder; and the last includes the well-known and largely used
gelatine compounds, viz., gelignite and gelatine dynamite, and also tonite
No. 3, &c.

In the year