THE MILITARY AEROPLANE	5
possible; but only the fighter can destroy the bomber
before he can drop his bombs, and make bomber
excursions so costly to the raiding force that they
must be discontinued. Day bombing in fine weather
was virtually abandoned by the Germans after the
famous occasion on which the fighters of the Royal
Air Force claimed 185 victims in one day. On that
day—15 September 1940—the British obtained
their first great victory of the war. And it passed
without the country's realizing that a victory in the
military sense had been won.
That day of tremendous destruction put an end,
for the time being if not for ever, to the German
belief that it could defeat Great Britain by means of
mass air-raids. Thereafter the Germans used their
bombers sparingly by day, restricting them mostly
to the coastal towns or allowing single machines to
make daylight attacks on London only when good
cloud cover was to be had. That defeat of a
cherished German plan was the equivalent of
repelling an invasion. It forced the Germans back
on to the uncertainties of night bombing and then
to concentrated night raids on the centres of cities
when they found that by night they could rarely hit
a selected target. It left the Germans with the
opportunity to do wanton and vicious damage by
night, but it deprived them of the power to do
precise and particular damage of military value.
Those battles of the autumn of 1940 showed that,
given a strong and determined defence, the
bombers can still be routed. The air supremacy
which guarantees a passage for the day bombers can
only be gained by the fighters. The fighters there-
fore are the key to successful air warfare. They hold