boys who come over to France for this work will be
subject to rapid and frequent variations in altitude. It is a
common occurrence to dive vertically from six thousand to ten
thousand feet with the motor pulling hard.

Sharpness of vision is imperative. Otherwise the enemy may escape
or the aviator himself will be surprised or mistake a friendly
machine for a hostile craft. The differences are often merely
insignificant colours and details.

America's aviators must be men who will be absolute masters of
themselves under fire, thinking out their attacks as their fight
progresses.

Experience has shown that the chaser men should weigh under 180
pounds. Americans from the ranks of sport, youth who have played
baseball, polo, football, or have shot and participated in other
sports will make the best fighting aviators.

CHAPTER VII

SOME METHODS OF THE WAR IN THE AIR

The fighting tactics of the airmen with the various armies were
developed as the war ran its course. As happens so often in the
utilization of a new device, either of war or peace, the manner of
its use was by no means what was expected at the outset. For the
first year of the war the activities of the airmen fell far short of
realizing Tennyson's conception of

The nations' airy navies grappling in the central blue.

The grappling was only incidental. The flyers seemed destined to be
scouts and rangefinders, rather than fighters. Such pitched combats
as there were took rather the form of duels, conducted with
something of the formality of the days of chivalry. The aviator
intent upon a fight would take his machine over the enemy's line and
in various ways convey a challenge to a rival--often a hostile
aviator of fame for his daring and skill in combat. If the duel was
to the death it would be watched usually from the ground by the
comrades of the two duellists, and if the one who fell left his body
in the enemy's lines, the victor would gather up his identification
disk and other personal belongings and drop them the next day in the
camp of the dead man's comrades with a note of polite regret.

It was all very daring and chivalric, but it was not war according
to twentieth century standards and was not long continued.

[Illustration: (C) U. & U.

_A Caproni Triplane._]

When at first the aviators of one side flew over the enemy's
territory diligently mapping out his