ils out over the lines of battle, so far above the earth
when necessary as to be out of range of the most powerful guns, and with
glasses looks down upon the whole country. His machine, whether it be a
dirigible balloon or airplane, is equipped with a wireless telegraph
instrument with which he is able to send brief messages back to his own
line or military headquarters. He can and does mark the changed
positions of the contending forces, note the entrenchments and
reinforcements, follow movements, and last but not least, as was
noticeable in one of the desperate attacks upon the German position in
June, 1917, swoop down upon the enemy, attack the lines and forces with
bombs, and rain bullets upon them from rapid-fire guns.

No longer can the enemy mask its heavy batteries or conceal them beneath
earthen mounds, plant them in corners of the forests or in clumps of
bushes without their being located. The "eyes of the sky," as the planes
are now termed, can spy them out. And when the airman has communicated
to his military commanders the positions of the opposing batteries, he
acts as a director in instructing the friendly gunners in finding the
range and cleaning out the enemy.

THE AIR SCOUT'S USEFULNESS.

The air scout can detect the enemy's lines of communication and raid it
with bomb attacks. Even when the land forces cannot reach the enemy with
gunfire he can rain missiles of all sorts upon them. Sometimes the
airman flies over the enemy lines and drops glittering tinsel or bright
metal devices, which falling to the ground serve as marks for the
artillerymen in finding the range.

Where the cavalry scout or creeping scout of days gone by could never
have proved successful, the airman has easily accomplished his purpose.
He has carried messages from one frontier to another in hours, when it
would have taken days for a scout on horseback or on foot to have
rendered the service, if they could have accomplished it at all. He has
eliminated distance.

Trench warfare developed in the world-war in a way that has never before
been deemed necessary or possible, but the miles of trenches which
conceal the men from the fire of the enemy are plainly visible to the
airmen. And armed with cameras having powerful telescopic lenses they
can photograph the entire scene and send to their own military
headquarters not mere indicated plans of the battle lines, but exact
photographs.

The war has shown conclusively that once th