of skill in the
European armies than was ever before realized, and the training of new
aviators, especially in the light of war experience, was carried on in
large part by convalescent members of the aviation corps who had seen
actual service in the field, so that the quota of recruits was not
only maintained but supplied, trained to a high degree of efficiency.

The progress of the war marked changes in the tactics of the aerial
services of the various armies. The French and English believed that
in the course of the war the Germans had lost a number of their most
skilled and intrepid aviators, and that the expert pilots were held in
readiness for more serious effort rather than being sacrificed for any
contests of doubtful outcome. The Germans for a time became more
cautious in their fights over the French lines, and in the summer and
autumn of 1915 seldom crossed. This probably was due in large part to
the increased number of aeroplanes at the disposal of the French and
English. Apparently for a number of weeks there was a decrease in the
reckless flights on the part of the Germans and desire to give battle,
and more attention was paid to developing tactical efficiency and
securing military results. Often their aeroplanes operated in
connection with the artillery, and in many cases their object was to
draw the Allies' machines within range of the German antiaircraft
artillery, which was efficiently served.

A complete chronicle of the flights and air battles of the period of
the war under review would contain a record where hardly a day passed
without some flight or contest of greater or less significance. A duel
between two hostile airmen might be of less importance than an
exchange of shots between members of opposing outposts, yet it might
involve heroic fighting and a skillful manipulation of aeroplane and
machine gun, when one or both of the contestants might be thrown
headlong to the ground. So for these pages we may select some of the
more significant of the battles in the air with the understanding that
many of those ignored were not without their vital interest.

CHAPTER LVI

ZEPPELIN RAIDS--ATTACKS ON GERMAN ARMS FACTORIES--GERMAN OVER-SEA
RAIDS

The second year of the war opened with a spirited combat between the
German and French aeroplanes, on August 1, 1915, when six attacking
German machines engaged fifteen French machines over Chateau Salins.
This fight, which at the time was widely disc