I'll have a pipe."

He fumbled in his pocket as he stood in the lee of a block of granite,
sheltered from the cold night wind, found the pipe, and raised it to his
lips to blow through the stem, but stopped short with every sense on the
alert, for from below to his left he heard a light chirp such as might
have been given by a bird, but which he argued certainly was not, for he
knew of no bird likely to utter such a note at that time of the evening,
when the flood of darkness had risen and risen till it had filled up
everything high above the highest kopje that dotted the plain.

"Couldn't be a signal, could it?" he said to himself. "Yes," he said
directly after, for the chirp was answered from lower down.

Dickenson softly swung the case of his telescope round to his back out
of the way, and took out his revolver without making a sound, listening
intently the while, and at the end of a long minute he made out a low
whispering close at hand; but he could not place it exactly, for the
sounds seemed to be reflected back from the face of the rock directly in
front of him.

"I wish it wasn't so dark," he said, and screwing up his lips, he tried
to imitate the chirp, and so successfully that it was answered.

"Must be one of our sentries," he thought, and he hesitated as to his
next proceeding.

"Don't want to challenge and raise a false alarm," he said; "but last
night's work makes one so suspicious. I'll let them challenge me."

He turned to descend softly from where he had climbed to, and his foot
slipped on the weather-worn stone, so that he made a loud scraping sound
in saving himself from a fall; but not so loud that he was unable to
hear the scuffling of feet close at hand, followed directly after by
dead silence.

His finger was on the trigger of his pistol, and he was within an ace of
firing in the direction of the noise, but refrained, and contented
himself with walking as sharply as he could towards it with outstretched
hands, for overhanging rocks made the place he was in darker than ever,
and he was reduced to feeling his way. Then stopping short with a sense
of danger being close at hand, he gave the customary challenge, to have
it answered from behind him; and the next minute he was face to face
with a sentry.

"I thought I heard something, sir," said the man. "Then it was you?"

"No, no," said Dickenson; "I heard it too--a low chirp like a bird."

"No, no, sir; not that--a sound as if some on