"But why take life so seriously?" responded Dan. "These savages spend a long time in bartering; we'll get there before they're through. Besides Slythe will wait to see if you will send the two hundred slaves to buy the princess."
"I'm not sure, Dan. We'd better push along as fast as we can. If Mobogoma offers enough, Slythe won't take any chances on a slip-up."
Before another hour had gone by, the riders were wilted with the heat and famished for food and drink. A green spot in the distance made them urge their horses on toward the grove of palm trees.
"Come on, let's hurry," cried Dan. "We can't get to that spring quick enough to suit me." The boy dug his heels into the horse's sides. The spirits of the men rose at the prospect of a spring of clear water and the shade of the palm trees beckoned them. Dan broke into a college song and the tribesmen took up the air and shouted it at the top of their lungs.
Suddenly Raal spoke in a voice trembling with excitement. "Look O Master, across the desert! Those are the Arab raiders!"
Raal pointed to the horizon, still wavering with heat, and Dick adjusted his binoculars.
At first he saw only a long straggling line of moving objects that resembled a giant centipede with countless legs and undulating back. Finally Dick made out a caravan of camels striding in single file and accompanied by Arab horsemen. They were so far away that Dick could not see them without the glasses, although Raal's sharp eyes had distinguished them.
Dick gasped. "Arabs! You're right, Raal. Maybe they are the ones we are after. Give orders for the warriors to have their weapons ready and be on the alert. Then let's go!"
To encourage the men, Dan once more burst into song. The tired horses caught the spirit and leaped ahead for a few minutes then began to lag. The heat was intense, the sand, catching the sun's rays dazzled the eyes and made them burn.
But no matter how fast they rode, the oasis seemed as far away as ever. The caravan was lost in the shimmering haze.
"Who would have believed that it was so far away?" grumbled Dan Carter. At that moment he caught sight of Dick's face. It was pale and troubled.
"What's the matter, old sport?" Dan asked anxiously. "Are you sick or something? Better take a sip of that precious water in the bag."