erry never finished that sentence, for as he was speaking came
cries of alarm from outside the hospital and the firing of several
guns, while some one shouted:

"An air raid! An air raid! The Huns are coming!"

CHAPTER XXI

A VISITOR

Jerry Hopkins, with his two chums and some of the hospital patients
who were able to move about, rushed toward the sound of the shouting
and firing. Jerry's leg wound was healed, and save for a slight limp
he was all right again.

The boys saw a group of soldiers gathered about a battery of guns
erected a short time before to repel air raids. And that this was now
a time to use the weapons was evident after a glance aloft.

For, hovering just below the clouds, were three big Hun planes, and
that they had come over the lines to bomb the American positions was
only too evident.

There was no time to stop and inquire how the hostile aircraft had
managed to elude the vigilance of the Allied airmen at the front. It
was time to act and act promptly, and at once the anti-aircraft
batteries opened, while word was quickly telephoned to the nearest
aerodrome, so that American, French, or British fliers might ascend to
attack the Germans. It was the shooting at the Hun planes with the
guns nearest the hospital that had broken in on Jerry's remarks.

"They won't bomb the hospital, will they?" asked Ned, in wonder.

"They're very likely to," declared Jerry. "Then later on they'll claim
they couldn't see the red crosses on the roof, or else they'll say
they meant to drop bombs on an ammunition dump or a railroad center
and they miscalculated the distance--the beasts!"

If the Huns intended to bomb the hospital now it would not be the
first time they had done such a dastardly trick. And that they
purposed sending down explosives somewhere in the neighborhood was
evident from the tactics of the hostile machines.

They flew about, so high above the group of buildings containing the
wounded and convalescents as to make it difficult to hit them, and
appeared to be waiting their best chance to drop a bomb where it would
do the most damage.

Meanwhile, nurses and orderlies were moving out their charges into the
open, so there would be less likelihood of their being caught in the
collapsed structures.

For a few minutes the scene was one of wild confusion, and then army
discipline was established and matters went on as they should. Ned,
Bob, and Jerry helped in taking out the wounded, w