nd a finer sport than shooting ducks came
into vogue. This quickly led to the carrying of machine guns. Ingenuity
in devising sights to compensate for the speed of our own machines and
to gauge a proper deflection according to the speed and angle of
approach of the enemy machine, soon decreased the advantage the enemy
aviators had through superior numbers.

For example, if our machine was flying at the rate of one hundred miles
per hour and the enemy's machine was travelling past us in the opposite
direction at an equal rate, our fore-sight nullified our motion and
enabled us to shoot as if from a stationary base, while our back-sight
helped us to gauge that imaginary point at which to shoot where our
bullets and the enemy machine would meet. In other words, we shot at an
enemy machine although we ourselves were travelling rapidly, exactly as
a sportsman shoots at a bird on the wing.

Then a new aeroplane was developed, the single-seater tractor, with a
Vickers gun, synchronized to shoot through the rapidly revolving
propeller so as to avoid the blades. These machines were used to patrol
the lines and keep enemy machines from crossing, or to accompany a
reconnaissance machine as protector; for they were very much faster,
easier to manoeuvre, and altogether very much more efficient fighters.
At first they operated singly, but it was soon discovered that two of
these scout machines operating together invariably obtained better
success than when operating alone. This led to formation flying, and up
to the cessation of hostilities these formations grew in size and varied
in shape.

The reconnaissance work was soon divided into classes: long and short
reconnaissance and photographic reconnaissance. The long reconnaissance
dealt with enemy movements far behind the lines; the short
reconnaissance with enemy activities near the front. The photographic
reconnaissance consisted of taking aerial photographs of everything of
military importance within flying radius. These photographs pieced
together showed the enemy defences along the entire British front and
their changes from day to day.

Wireless apparatus was soon attached to aeroplanes, and this enabled an
aviator to communicate with people on the ground many miles away; and so
what was called artillery observation was developed. Roughly speaking,
this is the direction of the fire of our batteries against enemy
targets; but, just as specialization came in reconnaissance an