m an aeroplane. No heavy bombs were
available, but floating charges of various weights, from 2-1/4 pounds to
40 pounds, were fired electrically from a destroyer, while Maurice
Farman seaplanes flew at various heights directly above the explosion.
Again the effect upon the machines was less than had been anticipated.
The general conclusion was that an aeroplane flying at a height of 350
feet or more could drop a hundred-pound bomb, containing forty pounds of
high explosive, without danger from the air disturbance caused by the
explosion.

A good war machine aims at combining the safety of the operator with a
high degree of danger to the victim. The second of these requirements
was the more difficult of fulfilment, and was the subject of many
experiments. Until the war took the measure of their powers, the German
Zeppelins preoccupied attention, and were regarded as the most important
targets for aerial attack. The towing of an explosive grapnel, which,
suspended from an aeroplane, should make contact with the side of an
airship, was the subject of experiments at Eastchurch. This idea,
though nothing occurred to prove it impracticable, was soon abandoned
in favour of simpler methods--the dropping, for instance, of a series of
light bombs with sensitive fuses, or the firing of Hales grenades from
an ordinary service rifle. To make these effective, it was essential
that they should detonate on contact with ordinary balloon fabric, and
preliminary experiments were carried out at the Cotton Powder Company's
works at Faversham in October 1913.

When two sheets of fabric, stitched on frames to represent the two skins
of a rigid airship, were hit by a grenade of the naval type with a
four-ounce charge, it was found that the front sheet was blown to shreds
and the rear sheet had a hole about half a foot in diameter blown in it.
Later experiments at Farnborough against balloons filled with hydrogen,
and made to resemble as nearly as possible a section of a rigid airship,
were completely successful. Firing at floating targets, and at small
target balloons released from the aeroplanes, was practised at
Eastchurch. It was found that, with no burst or splash to indicate where
the shot hit, this practice was unprofitable. The effective use of
small-bore fire-arms against aircraft was made possible by two
inventions, produced under the stress of the war itself, that is to say,
of the tracer bullet, which leaves behind it in the air a v