age. If the pilot be unaccompanied and entirely dependent upon
his own resources he cannot hope to fire vertically above him, for
the simple reason that in so doing he must relinquish control of his
machine. A rifle cannot possibly be sighted under such conditions,
inasmuch as it demands that the rifleman shall lean back so as to obtain
control of his weapon and to bring it to bear upon his objective. Even
if a long range Mauser or other automatic pistol of the latest type be
employed, two hands are necessary for firing purposes, more particularly
as, under such conditions, the machine, if not kept under control, is
apt to lurch and pitch disconcertingly.

Even a colleague carried for the express purpose of aggression is
handicapped. If he has a machinegun, such as a Maxim or a mitrailleuse,
it is almost out of the question to train it vertically. Its useful
vertical training arc is probably limited to about 80 degrees, and
at this elevation the gunner has to assume an extremely uncomfortable
position, especially upon an aeroplane, where, under the best of
circumstances, he is somewhat cramped.

On the other hand the man in the aeroplane above holds the dominating
position. He is immediately above his adversary and firing may be
carried out with facility. The conditions are wholly in his favour.
Sighting and firing downwards, even if absolutely vertically, imposes
the minimum physical effort, with the result that the marksman is able
to bring a steadier aim upon his adversary. Even if the machine be
carrying only the pilot, the latter is able to fire upon his enemy
without necessarily releasing control of his motor, even for a moment.

If he is a skilled sharpshooter, and the exigencies demand, he can
level, sight, and fire his weapon with one hand, while under such
circumstances an automatic self-loading pistol can be trained upon the
objective with the greatest ease. If the warplane be carrying a second
person, acting as a gunner, the latter can maintain an effective rifle
fusillade, and, at the same time, manipulate his machine-gun with no
great effort, maintaining rifle fire until the pilot, by manoeuvring,
can enable the mitrailleuse or Maxim to be used to the greatest
advantage.

Hence the wonderful display of tactical operations when two hostile
aeroplanes sight one another. The hunted at first endeavours to learn
the turn of speed which his antagonist commands. If the latter is
inferior, the pursued can eith