of adequate observation, which is the primary object of
aerial attack and defence, the British have won consistently. At no time
has the R.F.C. been obliged to modify its duties of reconnaissance,
artillery spotting, photography, or co-operation with advancing
infantry, which was introduced successfully last summer. On the
contrary, each of these functions, together with bombing and "ground
stunts" from low altitudes, has swollen to an abnormal extent.

An idea of the vastness of our aerial effort on the British front in
France can be gathered from the R.F.C. work performed on a typical "big
push" day.

Throughout the night preceding an advance, several parties, laden with
heavy bombs, steer by compass to Hun headquarters or other objectives,
and return no longer laden with bombs. The first streak of daylight is
the herald of an exodus from west to east of many score fighting craft.
These cross the lines, hover among the Archie bursts, and drive back or
down all black-crossed strangers within sight. Some of them go farther
afield and attack the Boche above his own aerodromes. Such enemy craft
as manage to take the air without meeting trouble from the advanced
offensive patrols are tackled by the scouts near the lines. The few that
travel still farther eastward with the intention of swooping on our
observation machines, or of themselves gathering information, receive a
hearty welcome from our defensive patrols.

The British two-seaters are thus free to direct the artillery, link the
attacking infantry with headquarters, and spy out the land. As soon as
the early morning light allows, a host of planes will be darting
backward and forward over the trench-line as they guide the terrific
bombardment preliminary to an attack. Other machines are searching for
new emplacements and signs of preparation behind the enemy trenches.
Several formations carry out tactical reconnaissances around an area
stretching from the lines to a radius twenty miles east of them, and
further parties perform strategic reconnaissance by covering the
railways, roads, and canals that link the actual front with bases thirty
to ninety miles behind it. When, at a scheduled time, the infantry
emerge over the top behind a curtain of shells, the contact patrol buses
follow their doings, inform the gunners of any necessary modifications
in the barrage, or of some troublesome nest of machine-guns, note the
positions held by the attackers, collect signals fro