e choked. Only birds of the
air, of all the living, had remained free of their element, floating
over the battling below them, as blithe as if men had not sown the lower
spaces with slaughter.

And now in this night of spring, one was calling to its mate. The
Commandant heard it, and struck its note on the upper keyboard.

"Every sound in nature has its key," he said; "the cry of the little
bird has it, and the surf at Nieuport."

"And the shells?" asked Hilda.

"Yes, the shells, they have it," he answered gravely; "each one of them,
as it whistles in the air, is giving its note. You have heard it?"

"Yes," answered Hilda.

"Why, this," he said. He held his hands widely apart to indicate the
keyboard--"this is only a little human dipping, like a bucket, into the
ocean waves of sound. It can't give us back one little part of what is.
Only a poor, stray sound out of the many can get itself registered. The
rest drift away, lost birds on the wing. The notes in between, the
splintered notes, they cannot sound on our little instruments."

A silence had fallen on the group. Out of the hushed night that covered
them, a moaning grew, that they knew well. One second, two seconds of
it, and then the thud fell somewhere up the line. As the shell was
wailing in the air, a hidden string, inside the frame, quivered through
its length, and gave out an under-hum. It was as if a far away call had
rung it up. One gun alone, out of all the masked artillery, had found
the key, and, from seven miles away, played the taut string.

"There is one that registers," said the Commandant; "the rest go past
and no echo here."

Firmly he struck the note that had vibrated.

"That gun is calling for me," said he; "the others are lost in the
night. But that gun will find me."

"You talk like a soothsayer," said Mrs. Bracher, with a sudden gesture
of her hand and arm, as if she were brushing away a mist.

"It's all folly," she went on, "I don't believe it. Good heavens, what
is that?" she added, as a footstep crunched in the hall-way. "You've got
me all unstrung, you and your croaking."

An orderly entered and saluted the Commandant.

"They've got the range of the Station, mon Commandant," he reported;
"they have just sent a shell into the tracks. It is dangerous in the
look-out of the house. Do you wish Victor to remain?"

"I will relieve him," said the Commandant, and he left swiftly and
silently, as was his wont.

Hilda returned to