“You’ll find we are far enough!” Quest remarked grimly.  “What do you make of this, Professor?”

He pointed to the little sandy knoll with its sparse covering of grass, deserted—­with scarcely a sign, even, that it had been the resting place of the caravan.  The Professor gave vent to a little exclamation.

“Our guides!” he demanded.  “And the camels!  What has become of them?”

“I woke you up to ask you that question?” Quest replied, “but I guess it’s pretty obvious.  We might have saved the money we gave for those rifles in Port Said.”

The Professor hurried off towards the spot where the encampment had been made.  Suddenly he stood still and pointed with his finger.  In the clearer, almost crystalline light of the coming day, they saw the track of the camels in one long, unbroken line stretching away northwards.

“No river near, where they could have gone to water the camels, or anything of that sort, I suppose?” Quest asked.

The Professor smiled.

“Nothing nearer than a little stream you may have heard of in the days when you studied geography,” he observed derisively,—­“the Nile.  I never liked the look of those fellows, Quest.  They sat and talked and crooned together after Hassan’s death.  I felt that they were up to some mischief.”

He glanced around a little helplessly.  Quest took a cigar from his case, and lit it.

“To think that an old campaigner like I am,” the Professor continued, in a tone of abasement, “should be placed in a position like this!  There have been times when for weeks together I have slept literally with my finger upon the trigger of my rifle, when I have laid warning traps in case the natives tried to desert in the night.  I have even had our pack ponies hobbled.  I have learnt the secret of no end of devices.  And here, with a shifty lot of Arabs picked up in the slums of Port Said, and Hassan, the dragoman, dying in that mysterious fashion, I permit myself to lie down and go to sleep!  I do not even secure my rifle!  Quest, I shall never forgive myself.”

“No good worrying,” Quest sighed.  “The question is how best to get out of the mess.  What’s the next move, anyway?”

The Professor glanced towards the sun and took a small compass from his pocket.  He pointed across the desert.

“That’s exactly our route,” he said, “but I reckon we still must be two days from the Mongars, and how we are going to get there ourselves, much more get the women there, without camels, I don’t know.  There are no wells, and I don’t believe those fellows have left us a single tin of water.”

“Any chance of falling in with a caravan?” Quest enquired.

“Not one in a hundred,” the Professor replied gloomily.  “If we were only this short distance out of Port Said, and on one of the recognised trade routes, we should probably meet half-a-dozen before mid-day.  Here we are simply in the wilds.  The way we are going leads to nowhere and finishes in an utterly uninhabitable jungle.”