r opposite or within sight of them.

As the sailor had said, any dark object of the size of a sixpence would
be seen if presented above the smooth combing of snow-white sand; and it
was evident to all that for one of them to look over it might lead to
their being discovered.

While discussing this point, they knew that some time had elapsed; and,
although the eyes they dreaded might still be distant, they could not
help thinking, that they were near enough to see them if only the hair
of their heads should be shown above the sand.

They reflected naturally. They knew that these sons of the desert must
be gifted with keen instincts; or, at all events, with an experience
that would enable them to detect the slightest "fault" in the aspect of
a landscape, so well-known to them, in short, that they would notice
anything that might appear "abnormal" in it.

From that time their situation was one of doubt and anxiety. They dared
not give even as much as a glance over the smooth, snow-white sand.
They could only crouch behind it, in anxious expectation; knowing not
when that dubious condition of things could be safely brought to a
close.

Luckily they were relieved from it, and sooner than they had expected.
Colin it was who discovered a way to get out of the difficulty.

"Ha!" exclaimed he, as an ingenious conception sprang up in his mind.
"I've got an idea that'll do. I'll watch these fellows, without giving
them a chance of seeing me. That will I."

"How?" asked the others.

Colin made no verbal reply; but instead, he was seen to insert his
telescope into the sand-parapet, in such a way that its tube passed
clear through to the other side, and of course commanded a view of the
beach, along which the two forms were advancing.

As soon as he had done so, he placed his eye to the glass, and in a
cautious whisper announced that both the horseman and camel-rider were
within his "field of view."

CHAPTER SIXTEEN.

THE TRAIL ON THE SAND.

The tube of the telescope, firmly embedded in the sand, kept its place
without the necessity of being held in hand. It only required to be
slightly shifted as the horseman and camel-rider changed place, so as to
keep them within its field of view.

By this means our adventures were able to mark their approach and note
every movement they made, without much risk of being seen themselves.
Each of them took a peep through the glass to satisfy their curiosity,
and then the i