posed at their posts instead of within the comparative snugness of
their kennel-like patrol tents, needed but little rousing in the event
of the expected happening. But strict orders for silence had been
issued, also that no light was to be struck on any pretext whatever;
wherefore these shivering ones were perforce denied the solace of the
warm and comforting pipe. The troop-horses on the picket lines were
beginning to bestir themselves, as an occasional snort and stamp would
testify.

The Commandant came out of one of the huts which had been erected for
the use of the officers; he had not slept in it, any more than that
night had any man under his command, officer or private trooper. He
glanced upward, as the lightening of the mist showed a pale, wrack-swept
moon, then held up against the latter something that looked uncommonly
like an ordinary large-sized pickle-bottle. No newly invented
projectile was this, however, it being in fact just what it looked, and
it contained something nondescript of the lizard tribe, reposing
motionless on the harmless-looking chemical which constituted the jar a
miniature lethal chamber. For the cool, self-possessed officer in
command of the frontier force was known to science as an enthusiastic
naturalist, as we have already pointed out.

He did not start in the least at the sound of an almost imperceptible
tread behind him.

"That you, Greenoak?" was all he said, without taking his attention off
the jar. "My specimen's dead by now. I think, though, I'll put him
inside the hut in case of accidents." Then, reappearing, "Well? I
suppose we shall be hard at it in an hour?"

"Less than that," replied Harley Greenoak. "Listen!"

Out in the mist the shrill, long-drawn, laughing bay of a jackal rang
out, then again. It was answered by another, on the opposite side of
the camp, and about at the same distance from it.

"That doesn't seem to ring quite true, does it?" said Greenoak.

"No, it doesn't. And there's a mathematical precision about it unusual
among the beasts of the field," was the answer.

Greenoak nodded.

"Right you are, Commandant," he said. "Listen. The mathematical
calculation keeps up."

For, on the other front came the same sound at exactly the same distance
in that direction. It was answered by the two who had first given
tongue, but now all these three voices seemed to be receding. This
ordinary nocturnal sound would have attracted the attention--