red desert, but where the glint of steel or the twinkle of
white helmet for which he yearned?

And soon they cleared the obstacle in their front. It spindled away into
nothing, as a streak of dust would which has been blown across an empty
room. It was curious to see that when it was so narrow that one could
almost jump it, the Arabs would still go for many hundreds of yards
rather than risk the crossing. Then, with good, hard country before them
once more, the tired beasts were whipped up, and they ambled on with a
double-jointed jog-trot, which set the prisoners nodding and bowing in
grotesque and ludicrous misery. It was fun at first, and they smiled
at each other, but soon the fun had become tragedy as the terrible
camel-ache seized them by spine and waist, with its deep, dull throb,
which rises gradually to a splitting agony.

"I can't stand it, Sadie," cried Miss Adams, suddenly. "I've done my
best. I'm going to fall."

"No, no, Auntie, you'll break your limbs if you do. Hold up, just a
little, and maybe they'll stop."

"Lean back, and hold your saddle behind," said the Colonel. "There,
you'll find that will ease the strain." He took the puggaree from his
hat, and, tying the ends together, he slung it over her front pommel.
"Put your foot in the loop," said he. "It will steady you like a
stirrup."

The relief was instant, so Stephens did the same for Sadie. But
presently one of the weary doora camels came down with a crash, its
limbs starred out as if it had split asunder, and the caravan had to
come down to its old sober gait.

"Is this another belt of drift sand?" asked the Colonel, presently.

"No, it's white," said Belmont. "Here, Mansoor, what is that in front of
us?"

But the dragoman shook his head.

"I don't know what it is, sir. I never saw the same thing before."

Right across the desert, from north to south, there was drawn a white
line, as straight and clear as if it had been slashed with chalk across
a brown table. It was very thin, but it extended without a break from
horizon to horizon. Tippy Tilly said something to the dragoman.

"It's the great caravan route," said Mansoor.

[Illustration: The great caravan route p 174]

"What makes it white, then?"

"The bones."

It seemed incredible, and yet it was true, for as they drew nearer they
saw that it was indeed a beaten track across the desert, hollowed out by
long usage, and so covered with bones that they gave the impression of
a