of the summer sky--a German aeroplane.

At a height of seven or eight thousand feet the target seems almost
stationary, when really it is going somewhere between fifty and ninety
miles an hour. It has all the heavens to itself, and to the British it is a
sinister, prying eye that wants to see if we are building any new
trenches, if we are moving bodies of troops or of transport, and where
our batteries are in hiding. That aviator three miles above the earth
has many waiting guns at his command. A few signals from his
wireless and they would let loose on the target he indicated.

If the planes might fly as low as they pleased, they would know all that
was going on in an enemy's lines. They must keep up so high that
through the aviator's glasses a man on the road is the size of a pin-
head. To descend low is as certain death as to put your head over
the parapet of a trench when the enemy's trench is only a hundred
yards away. There are dead lines in the air, no less than on the earth.

Archibald, the anti-aircraft gun, sets the dead line. He watches over it
as a cat watches a mouse. The trick of sneaking up under cover of a
noonday cloud and all the other man-bird tricks he knows. A couple of
seconds after that crack a tiny puff of smoke breaks about a hundred
yards behind the Taube. A soft thistledown against the blue it seems
at that altitude; but it would not if it were about your ears. Then it
would sound like a bit of dynamite on an anvil struck by a hammer
and you would hear the whizz of scores of bullets and fragments.

The smoking brass shell-case is out of Archibald's steel throat, and
another shell-case with its charge slipped into place and started on its
way before the first puff breaks. The aviator knows what is coming.
He knows that one means many, once he is in range.

Archibald rushes the fighting; it is the business of the Taube to side-
step. The aviator cannot hit back except through his allies, the
German batteries, on the earth. They would take care of Archibald if
they knew where he was. But all that the aviator can see is mottled
landscape. From his side Archibald flies no goal flags. He is one of
ten thousand tiny objects under the aviator's eye.

Archibald's propensities are entirely peripatetic. He is the vagabond
of the army lines. Locate him and he is gone. His home is where night
finds him and the day's duties take him. He is the only gun that keeps
regular hours like a Christian gentlema