describe these instruments in detail or tell much about our
instruction because I have given my oath never to reveal any of the
details of this work. I am permitted, however, to name some of these
instruments, such as the subterranean microphone, sizorscope,
horoscope, perpendicular and horizontal range finder, elongated
three-power French binocular, instruments for determining the height
of airplanes, etc. We had to acquire a practical knowledge in the use
of all these instruments, as they were to be our future implements of
warfare, and in matters of this kind, accuracy is of vast importance.
We also had to learn the signals of the French, British, Italian and
American aviators; the international Morse code; to send and receive
messages perfectly under all conditions; to have a practical knowledge
of the use of telephone and telegraph instruments; their attention and
repair; and how to keep the lines of communication in working order at
all times and under any and all conditions.

From this brief summary, it can be readily understood that the
Government crowded plenty of work upon us during those three weeks. At
the completion of the courses examinations were given, and only 86 of
us out of a class of 208 succeeded in reaching the required
percentage. Of the others most remained to take the course for
another three weeks, while a few were released from the work as not
qualified for that particular kind of service.

All the time that we were studying we were drilled just as though we
were actually at war. We were compelled to dig in, to find the range
on certain objects and to direct imaginary artillery fire upon them.
We had to find the range of airplanes that passed over us, just as
though they were enemy planes. This drilling was as near like actual
warfare as it was possible to make it and because of this, we grasped
the meaning of our work and the details very quickly.

We were also drilled thoroughly in the art of camouflage. To be
successful in camouflage, one must learn to imitate nature and that is
what we had to study, and one's tracks must always be covered. A
successful bit of camouflage not only deceives the eyes of the enemy
aerial observers, but it also deceives the lens of the enemy camera.
To make this perfectly clear, it should be said that the lens of
cameras used in warfare are exceedingly delicate and frequently when
the plate of an aerial photograph is developed, it reveals a spot that
means