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. “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 continuous white ribbon. Long, snouty heads were scattered everywhere, and the lines of ribs were so continuous that it looked in places like the framework of a monstrous serpent. The endless road gleamed in the sun as if it were paved with ivory. For thousands of years this had been the highway over the desert, and during all that time no animal of all those countless caravans had died there without being preserved by the dry, antiseptic air. No wonder, then, that it was hardly possible to walk down it now without treading upon their skeletons. “This must be the route I spoke of,” said Stephens. “I remember marking it upon the map I made for you, Miss Adams. Baedeker says that it has been disused on account of the cessation of all trade which followed the rise of the Dervishes, but that it used to be the main road by which the skins and gums of Darfur found their way down to Lower Egypt.” They looked at it with a listless curiosity, for there was enough to engross them at present in their own fates. The caravan struck to the south along the old desert track, and this Golgotha of a road seemed to be a fitting avenue for that which awaited them at the end of it. Weary camels and weary riders dragged on together towards their miserable goal.