m the battalion
headquarters, and by means of message bags dropped over brigade
headquarters report progress to the staff. If, later, a further advance
be made, the low-flying contact machines again play their part of
mothering the infantry.

Machines fitted with cameras photograph every inch of the defences
improvised by the enemy, and, as insurance against being caught
unprepared by a counter-attack, an immediate warning of whatever
movement is in evidence on the lines of communication will be supplied
by the reconnaissance observers. Under the direction of artillery
squadrons the guns pound the new Boche front line and range on
troublesome batteries.

The bombing craft are responsible for onslaughts on railways, supply
depots, garrison towns, headquarters, aerodromes, and chance targets.
Other guerilla work is done by craft which, from a height of anything
under a thousand feet, machine-gun whatever worthwhile objects they
spot. A column of troops on the march, transport, ammunition waggons, a
train, a stray motor-car--all these are greeted joyfully by the pilots
who specialise in ground stunts. And at every hour of daylight the
scouts and fighting two-seaters protect the remainder of the R.F.C. by
engaging all Huns who take to the air.

Doubtless, when sunset has brought the roving birds back to their nest,
there will be a few "missing"; but this, part of the day's work, is a
small enough sacrifice for the general achievement--the staff supplied
with quick and accurate information, a hundred or two Boche batteries
silenced, important works destroyed, enemy communications impeded, a
dozen or so black-crossed aeroplanes brought down, valuable photographs
and reports obtained, and the ground-Hun of every species harried.

The German Flying Corps cannot claim to perform anything like the same
amount of aerial observation as its British counterpart. It is mainly
occupied in fighting air battles and hampering the foreign machines that
spy on their army. To say that the German machines are barred altogether
from reconnaissance and artillery direction would be exaggeration, but
not wild exaggeration. Seldom can an enemy plane call and correct
artillery fire for longer than half an hour. From time to time a fast
machine makes a reconnaissance tour at a great height, and from time to
time others dart across the lines for photography, or to search for gun
positions. An appreciable proportion of these do not return. Four-fi