ch else at that height. They seem to be
able to descend suddenly for a short time to a very low altitude when
it is necessary and, in a large percentage of cases, to escape.
British aeroplanes have made reconnoissances at an altitude of only
one hundred yards.

Aeroplanes have made surprises in war nearly impossible, since in
modern warfare it would be necessary to shift at least a division to
produce any effect, and the movement of such a number of men would
certainly be visible to aeroplanes during the daytime. If such a
movement were performed at night, the presence of the division in a
new spot would almost certainly be detected by the aeroplanes in the
morning. The possession of a large and efficient aeroplane corps
reduces the surprises of war very nearly to nil, and proportionately
increases the importance of preparedness and of tactics.

The German aviators (and in fact all German observers, such as
infantry and cavalry patrols) make it a principle to avoid, if
possible, any combat; this is, of course, interpreted as cowardice by
the Allies, who seem eager for a fight on any terms. There is a
distinct reluctance among aviators for engaging in aerial duels. As
one French aviator said to me: "You are both killed and that does no
one any good." This reluctance is fairly universal, except with
British flyers.

The German aeroplanes signal their observations by means of a code
expressed in smoke balls. I never was able to obtain any theory as to
how this code works. This method of communication seems to be very
effective, as German shells sometimes arrive with singular accuracy
and immediateness. It is commonly reported that Germans also signal
with a suspended disc, but I have no personal knowledge of this
system. The French had no definite means of signaling from the air in
the early months of the war, and I believe this is still the case.
They make their observation and return to their base to report,
usually taking notes while aloft on maps and in note-books. I have no
personal knowledge of the British methods. The Austrian system of
signaling is by means of evolutions of the aeroplanes themselves. When
they observe a target they fly over it, and when directly above make
a sudden dip. They are observed during their evolutions with
instruments, so that the exact angle and hypothenuse at the moment of
this dip is known. They then make a circuit and come up from the rear
and again fly over the objective. As they