In this look round and another which followed, Frank found that the men of the bodyguard were fully on the alert, and that twice as many sentries as usual were about the place. But all was silent save a low murmur from the far-spreading city—a low, strange buzzing burr as if from some vast hive, suggesting that the whole place was awake and in expectation of something about to happen.

At last there were the faint indications of the coming day, but to the watchers even they seemed cold and strange, differing from the early dawns they were accustomed to in their journeys across the vast stretch of sand.

The light increased, and a strange restlessness, which they could not explain attacked the watchers. The drowsiness that had been felt from time to time had completely passed away, and while the Hakim sat looking stern and anxious, Sam relieved his feelings by making coffee, feeling sure all the time that no one would touch it, and Frank and the professor fidgeted about in and out to look at the camel-drivers seated as calmly as the quaint animals they tended, and then to see if the guard were still at their posts.

But there was no further sign of preparation for a start, and the chief of the guard was nowhere to be seen.

Sunrise came, and with it the hurrying of feet, which proved to be a large body of men making for the vast expanse of mud-houses nearest to the river, where the rough forts, of which Frank had never obtained a glimpse, lay. When the men had passed, the silence became oppressive once more, and Frank and his companion went in to find Harry nursing his arm, which had taken to throbbing violently.

Just then Sam was ready with the coffee, borne in a steaming brass pot in company with a brass tray and so many brass cups.

“You’ll have some coffee, gentlemen?” he said respectfully; “it will be so refreshing,” and setting down the tray he began, though no one answered, to fill the little cups.

At that moment there came from far away the dull, short report of a gun, and Sam nearly dropped the coffee pot.

“What’s that?” he cried, with his eyes starting widely open.

“A heavy gun,” said Harry, starting up. “Then this is what all this gathering meant.”