ilots to break off a fight, to simulate
defeat, or to descend in a vertical path. Similarly, little stress was
laid, at the beginning, on speed, for speed was not helpful to
reconnaissance, or on climb and height, for it was believed that at
three thousand feet from the ground a machine would be practically
immune from gunfire, and that reconnaissance, to be effective, must be
carried on below the level of the clouds. These misconceptions were soon
to be corrected by experience. Another, more costly in its consequences,
was that a machine-gun, when carried in an aeroplane, must have a large
arc, or cone, of fire, so that the gun might be fired in any direction,
up, down, or across. To secure this end guns had to be carried in the
front of a pusher machine, which is slower and more clumsy than a
tractor. But the difficulty of accurate firing from a flying platform at
an object moving with unknown speed on an undetermined course was found
to be very great. The problem was much simplified by the introduction of
devices for firing a fixed machine-gun through the tractor screw, so
that the pilot could aim his gun by aiming his aeroplane, or
gun-platform, which responds delicately and quickly to his control.

When the war began we were not inferior in aerodynamical knowledge to
the Germans or even to the French. Speaking at the Aeronautical Society
in February 1914, Brigadier-General Henderson said, 'If any one wants to
know which country has the fastest aeroplane in the world--it is Great
Britain'. This was the S.E. 4, a forerunner of the more famous S.E. 5.
If more powerful engines had been installed in the British machines of
1914, they would have given us a speed that the enemy could not touch.
But we were preoccupied with the needs of reconnaissance, and we cared
little about speed. In the early part of the war we hampered our
aeroplanes with fitments, cameras, and instruments, which were attached
as protuberances to the streamlined body of the aeroplane and made speed
impossible. In the Flying Corps itself an aeroplane thus fitted was
commonly called a Christmas tree. We thought too little of power in the
engine, a mistake not quickly remedied, seeing that the time which must
elapse between the ordering of an engine and its production in quantity
is, even under pressure, a period of about twelve months. The engines
available at the outbreak of the war for British military aircraft were
the seventy horse-power Renault and