that shows how uneducated your eyes are, and how much they have to
learn. I'm not very clever over such things, being best when I get
scent of a buried temple, tomb, or city. But this waste of nothingness
contains plenty to interest an observer, and I can help you a little if
you will try to make the best of our journey."

"I have told you I will," said Frank.

"Yes; so we'll begin at once, for you may believe me that we are not
going to journey fifteen or twenty miles to-day without seeing something
more interesting than sand. Here's my little binocular. Take it, and
we'll begin."

"First of all, though," said Frank, "are we bound for some particular
place this evening?"

"Of course. For another patch of water-holes. Ibrahim says they are
nothing like so good as those by the encampment, but they will do for
the night's halt. To-morrow we shall have to halt right in the desert
and depend upon the water we take with us. The next day we journey on
to fresh wells."

"I see," said Frank; "our journeys are regulated by the supplies of
water."

"Exactly. Water means life."

"And Ibrahim can trust to his knowledge of the country to go straight to
these places?"

"Yes; I have proved him over and over again. Now then: try the glass."

"Yes," said Frank, opening the case; "but tell me, do you mean to
collect birds, insects, fossils, and plants?"

"Certainly, everything we can find; but only to examine at the end of
the day. We must keep nothing; only make a few notes. Well, can you
see anything?"

"Not yet. It is rather awkward to get a steady look with the camel
moving."

"If you catch sight of anything worth looking at you can check your
steed."

"Yes, there's something moving yonder--a dog."

"I doubt it," said the professor. "Try again."

"It looks like a dog. What is it then--a fox? Ah, it is gone behind
those heaps yonder."

"Then the desert is not quite empty, Frank. Your dog or fox must be a
jackal; but I wonder at your seeing him in the daylight. Let me look at
your heap of sand."

"One minute; there are two somethings upon it. Two of those jackals
sitting on a heap, I suppose, by their holes. No; one of them has
stretched out two wings. Why, they're vultures."

"Better still. Now I'll look.--Thanks. Your eyes require a different
focus from mine. Yes. What I expected," said the professor, handing
back the glass. "Have another look at your sand heap; it will repay
observ