itself, is even
more so when it is remembered that the improvement in enemy
anti-aircraft guns drove our machines to carry out their work at
altitudes increasing up to 20,000 and even 22,000 feet, at which heights
the negatives had to be as distinct as those taken at 4,000 in the
earlier days of the war.

At the beginning of the Dardanelles operations our apparatus consisted
of one camera, a printing frame and a dark room lamp. The first
photographs were taken by Butler in April, 1915, from a H. Farman
machine at necessarily low altitudes. Butler was wounded in June and was
succeeded by Thomson, who alone made 900 exposures and sent in 3,600
prints.

In addition to the assistance of air photography to reconnaissance, the
war gave it great impetus as the handmaid of survey and mapping. It was,
in fact, the only means of mapping or correcting the maps of country
held by the enemy, which in certain cases, as at Gallipoli and in
Palestine, were very inaccurate.

By the end of the war photographic processes and equipment had reached a
high standard of excellence. There are still, however, certain
difficulties in regard to the production of accurate maps, which have
not been overcome, the most obvious being the necessity of an initial
framework of fixed points and of contouring. The subject is considered
so important that an "Air Survey Committee," consisting of
representatives of the Air Ministry, the Geographical section of the War
Office, the Ordnance Survey, the School of Military Engineering and the
Artillery Survey School, has recently been formed. In addition, the
School of Aeronautics of Cambridge University is studying the question.
The Survey of India and the Survey of Egypt are also conducting
experiments.

_Wireless._

From the outset, part of the German scheme of tactics was to batter down
resistance by means of superior weight of heavy armament, and with the
beginning of warfare of fixed position the observation and direction of
our artillery fire became as important as distant reconnaissance.
Besides its immense value in increasing the effect of the batteries, it
had the indirect advantage of more closely binding the ties of mutual
understanding between the air and ground troops, a point which
fortunately seems to have been misunderstood by the Germans. In
September, 1914, the first attempts were made to signal enemy movements
from the aeroplanes of a Headquarters Wireless Flight which had been
forme