with safety from powder guns in ordinary shells, provided the quantity
was small in proportion to the total weight of the shell--say five or
six per cent. But a new difficulty arises from the fact that it breaks
the shell up into very small pieces, and it is an unsettled question
among artillerists whether more damage is done to an enemy by breaking
a shell into comparatively large pieces and dispersing them a long
distance with a bursting charge of powder, which has a propulsive
force, or by breaking it with a detonating compound into fine pieces,
which are not driven nearly so far. When used against troops there is
also the objection to the high explosive shell that it makes scarcely
any smoke in bursting, and smoke at this point is useful to the
artillerist in rectifying his aim.

In the matter of shells for piercing armor, however, there are no two
opinions regarding the nature of the bursting charge. To pierce modern
armor at all a shell must be made of forged steel, so thick that the
capacity of the cavity for the bursting charge is reduced to
one-fourth or one-fifth of what it is in the common shell; the result
is that a charge of powder is frequently not powerful enough to burst
the shell at all; it simply blows the plug out of the filling hole in
the rear. In addition it is found that in passing through armor, the
heat generated is so great that the powder is prematurely ignited.

If then we can fill the small cavity in the shell with an explosive
which will not ignite prematurely, and yet will burst the shell
properly after it has passed through the armor, the problem will be
solved. Wet or paraffined gun-cotton can be made sluggish enough to
satisfy the first condition; but at present the difficulty is to make
it explode at all. The more sluggish the gun-cotton, the more powerful
must be the fuse exploders to detonate it, and such exploders are