Bickford fuse of the required length is cut clean and is inserted into a
detonator until it reaches the fulminate. The upper portion of the
detonator is then squeezed round the fuse with a pair of nippers. The
object of this is not only to secure that the full power of the detonator
may be developed, but also to fix the fuse in the cap (Fig. 34). When the
detonator, &c., is to be used under water, or in a damp situation, grease
or tallow should be placed round the junction of the cap with the fuse, in
order to make a water-tight joint. A cartridge is then opened and a hole
made in its upper end, and the detonator pushed in nearly up to the top.
Gun-cotton or tonite cartridges generally have a hole already made in the
end of the charge. Small charges of dry gun-cotton, known as primers, are
generally used to explode wet gun-cotton. The detonators (which are often
fired by electrical means) are placed inside these primers (Fig. 35).

[Illustration: FIG. 35. PRIMER.]

One of the forms of electric exploders used is shown in Fig. 36. This
apparatus is made by Messrs John Davis & Son, and is simply a small hand
dynamo, capable of producing a current of electricity of high tension.
This firm are also makers of various forms of low tension exploders. A
charge having been prepared, as in Fig. 34, insert into the bore-hole one
or more cartridges as judged necessary, and squeeze each one down
separately with a _wooden_ rammer, so as to leave no space round the
charge, and above this insert the cartridge containing the fuse and
detonator. Now fill up the rest of the bore-hole with sand, gravel, water,
or other tamping. With gelatine dynamites a firm tamping may be used, but
with ordinary dynamite loose sand is better. The charge is now ready for
firing.

[Illustration: FIG. 36.--ELECTRIC EXPLODER.]

CHAPTER VI.

_SMOKELESS POWDERS._

Smokeless Powder in General--Cordite--Axite--Ballistite--U.S. Naval
Powder--Schultze's E.G. Powder--Indurite--Vielle Poudre--Rifleite--
Cannonite--Walsrode--Cooppal Powders--Amberite--Troisdorf--Maximite--
Picric Acid Powders, &c., &c.

The progress made in recent years in the manufacture of smokeless powders
has been very great. With a few exceptions, nearly all these powders are
nitro compounds, and chiefly consist of some form of nitro-cellulose,
either in the form of nitro-cotton or nitro-lignine; or else contain, in
addition to the above, nitro-glycerine, with very often some such