owards
the end of 1916 appeared the R.E.8 with a Vickers synchronized gun and
a Lewis gun, which after many vicissitudes became the standard machine
for artillery work.

Systematic bombing was practised by nearly all types of machines, but
real accuracy was never obtained. Thus, the B.E.2c was first used in
formations, but with a full load of bombs it could not carry an
observer, and its moderate speed left it an easy prey to hostile
fighters. Early in 1916 appeared the Martinsyde single-seater bomber
with an endurance of 4-1/2 hours, and in 1917 the D.H.4 which was much
used for day-bombing. The F.E.2b pusher, discarded as a fighting
machine, became the principal night-bomber.

It was comparatively late in the war before special bombing machines
were evolved. They were then divided into day-bombers and night-bombers,
the D.H.9 and 9a machines being typical of the former and the Handley
Page of 1917--a large twin-engine aeroplane, the first really effective
night-bomber, of considerable carrying power but low performance--of the
latter. By November 8th, 1918, two super-Handley Pages were ready to
start to Berlin. They possessed a maximum range of 1,100 miles, a crew
of seven, four 350 horse-power Rolls-Royce engines, arranged in pairs, a
tractor and a pusher in tandem on either side of the machine, and, as
they would be compelled to fly both by night and day, a gun defence
system. The D.H.10a and the Vickers Vimy, for day and night bombing
respectively, were also being produced at the date of the Armistice.

In the early days of the war an aeroplane had little to fear above
4,000 feet. With the improvement of the anti-aircraft gun there was, by
the end of the war, no immunity at 20,000 feet. Very low flying for
attack was, however, being rapidly developed, and would have proved of
great effect in 1919. The aeroplane used for this purpose was the
single-seater fighter, and the Sopwith "Salamander," with two guns, a
speed of 125 miles an hour, and 650 lb. of armoured plates, was about to
make its appearance at the Armistice.

I have previously mentioned how dependent the improvement of design and
performance of aircraft has been upon the less simple and tardier
development of the engine. The invention of the light motor made
aviation possible, and development has synchronized with the evolution
of lighter, more powerful and more reliable engines. One of the most
difficult problems still confronting us is the productio