a general indifference to
shaving while in the field.

But Captain Mignot evidently had his own ideas of military smartness,
and these lads were all clean-shaven. They trooped in from their game,
under that little cloud of shrapnel smoke that still hung in the sky,
for all the world a crowd of overheated and self-conscious schoolboys
receiving an unexpected visit from the master of the school.

The path ended at the battery. In the centre of the guns was a raised
platform of wood, and a small shelter house for the observer or
officer on duty. There were five guns in pits round this focal point
and forming a circle. And on the platform in the centre was a curious
instrument on a tripod.

"The telemeter," explained Captain Mignot; "for obtaining the altitude
of the enemy's aeroplane."

Once again we all scanned the sky anxiously, but uselessly.

"I don't care to have any one hurt," I said; "but if a plane is coming
I wish it would come now. Or a Zeppelin."

The captain's serious face lighted in a smile.

"A Zeppelin!" he said. "We would with pleasure wait all the night for
a Zeppelin!"

He glanced round at the guns. Every gunner was in his place. We were
to have a drill.

"We will suppose," he said, "that a German aeroplane is approaching.
To fire correctly we must first know its altitude. So we discover that
with this." He placed his hand on the telemeter. "There are, you
observe, two apertures, one for each eye. In one the aeroplane is seen
right side up. In the other the image is inverted, upside down. Now!
By this screw the images are made to approach, until one is
superimposed exactly over the other. Immediately on the lighted dial
beneath is shown the altitude, in metres."

I put my eyes to the openings, and tried to imagine an aeroplane
overhead, manoeuvring to drop a bomb or a dart on me while I
calculated its altitude. I could not do it.

Next I was shown the guns. They were the famous
seventy-five-millimetre guns of France, transformed into aircraft guns
by the simple expedient of installing them in a pit with sloping
sides, so that their noses pointed up and out. To swing them round, so
that they pointed readily toward any portion of the sky, a circular
framework of planks formed a round rim to the pit, and on this runway,
heavily greased, the muzzles were swung about.

The gun drill began. It was executed promptly, skilfully. There was no
bungling, not a wrong motion or an unnecessary one, as