and not for the subjugation
of the airman, which is a minor consideration, inasmuch as he is
condemned to a descent when his craft receives a mortal wound.

Attempts have been and still are being made to adapt an explosive
projectile to this gun, but so far the measure of success achieved has
not proved very promising. There are immense difficulties connected
with the design of an explosive shell of this class, charged with a
high explosive, especially in connection with the timing. So far as
dependence upon percussive detonation is concerned there is practically
no difficulty. Should such a missile strike, say, the motor of an
aeroplane, or even the hull of the craft itself, the latter would be
practically destroyed. But all things considered, it is concluded that
more successful results are likely to be achieved by the armour-piercing
bullet striking the mechanism than by an explosive projectile.

The Krupp company fully realised the difficulties pertaining to the
projectile problem in attacks upon aerial craft. So far as dirigibles
are concerned shrapnel is practically useless, inasmuch as even should
the bag be riddled by the flying fragments, little effective damage
would be wrought--the craft would be able to regain its haven.
Accordingly efforts were concentrated upon the perfection of two new
types of projectiles, both of which were directed more particularly
against the dirigible. The one is the incendiary shell--obus
fumigene--while the other is a shell, the contents of which, upon coming
into contact with the gas contained within the gas-bag, set up certain
chemical reactions which precipitate an explosion and fire.

The incendiary shells are charged with a certain compound which is
ignited by means of a fuse during its flight. This fuse arrangement
coincides very closely with that attached to ordinary shrapnel, inasmuch
as the timing may be set to induce ignition at different periods, such
as either at the moment it leaves the gun, before, or when it strikes
the envelope of the dirigible. The shell is fitted with a "tracer,"
that is to say, upon becoming ignited it leaves a trail of smoke,
corresponding with the trail of a rocket, so that its passage through
the air may be followed with facility. This shell, however, was designed
to fulfil a dual. Not only will it fire the gaseous contents out of the
dirigible, but it has an explosive effect upon striking an incombustible
portion of the aircraft, such as