d
fighting, so now machines specialized in artillery observation. To-day
the efficiency of the artillery depends largely upon its direction from
the air. For instance, when a battery takes over a new area the gunners
may be called upon to fire at certain targets, such as cross-roads or
houses used as infantry headquarters or ammunition and stores dumps, at
a moment's notice. Consequently, if these targets are registered by
aeroplane, all the gunners have to do when called upon to open fire is
to refer to their registration book which will give them the necessary
angles to use on their sights, then, by allowing for the temperature of
the day and the direction and velocity of the wind, their shooting is
certain to be far more accurate than it would be if the target had not
been previously registered. The registration of targets to-day without
the use of areoplanes is very often impossible.

The registration of targets from the air, however, is not the most
important part of this work. For instance, a machine will be flying over
enemy territory; the observer will see the flash of an enemy gun and
will pin-point its position on his map, which is marked off into large
and small lettered and numbered squares. This operation enables him to
send by wireless what is known as a zone call, giving the exact
location of the enemy battery to all of our batteries within range. The
enemy battery then has to move suddenly, if it is ever to move at all.

Barrages can also be controlled very efficiently from the air, so,
considering the comparatively short time that aeroplanes have been used
in this work and the wonderful results that have been obtained, it does
not take much imagination to see the necessity for all future artillery
officers to be trained as aviators.

In the earlier stages of the war it was very difficult for Headquarters
to keep in close touch with the infantry during a "push"; consequently,
considerable loss of life might result from one portion of the line
advancing out of contact with another. Probably the eagerness of raw
troops to keep on advancing regardless of their objective has led to a
considerable and unnecessary loss of life. The aeroplane can be used in
these situations to great advantage, and after the development of what
is known as "contact patrol" the aeroplane became the connecting link
between Headquarters and the infantry.

It was not until 1916 that the full powers of the aeroplane as an
offensi