uld be heard long before they could be seen,
range finders, and other devices for the purpose of gauging the
distance and fixing the direction of an approaching enemy.

Some brief attention may here be given to the various types of
anti-aircraft guns. These differ very materially in type and weight
in the different belligerent armies and navies. They have but one
quality in common, namely that they are most disappointing in the
results attained. Mr. F. W. Lancaster, the foremost British
authority on aircraft, says on this subject:

"Anti-aircraft firing is very inaccurate, hence numbers of guns are
employed to compensate."

[Illustration: Photo by International Film Service.

_German Air Raiders over England._

_In the foreground three British planes are advancing to the
attack._]

That is to say that one or two guns can be little relied upon to put
a flyer _hors du combat_. The method adopted is to have large
batteries which fairly fill that portion of the air through which
the adventurous airman is making his way with shells fired rather at
the section than at the swiftly moving target.

"Archibald," the British airmen call, for some mysterious reason, the
anti-aircraft guns employed by their enemies, sometimes referring to a
big howitzer which made its appearance late in the war as "Cuthbert."
The names sound a little effeminate, redolent somehow of high teas and
the dancing floor, rather than the field of battle. Perhaps this was
why the British soldiers adopted them as an expression of contempt for
the enemy's batteries. But contempt was hardly justifiable in face of
the difficulty of the problem. A gun firing a twenty-pound shrapnel
shell is not pointed on an object with the celerity with which a
practised revolver shot can throw his weapon into position. The gunner
on the ground seeing an airplane flying five thousand feet above
him--almost a mile up in the air--hurries to get his piece into
position for a shot. But while he is aiming the flyer, if a high-speed
machine, will be changing its position at a rate of perhaps 120 miles
an hour. Nor does it fly straight ahead. The gunner cannot point his
weapon some distance in advance as he would were he a sportsman intent
on cutting off a flight of wild geese. The aviator makes quick
turns--zigzags--employs every artifice to defeat the aim of his enemy
below. Small wonder that in the majority of cases they have been
successful. The attitude of the airmen towa