"Doctor! doctor!" shouted Kennedy in an agitated voice.

"What is the matter, Dick?"

"Is it an illusion? Can it be possible?"

"What do you mean?"

"Wait!" and so saying, the Scot wiped the sights of his spy-glass carefully, and looked through it again intently.

"Well?" questioned the doctor.

"It is he, doctor!"

"He!" exclaimed Ferguson with emotion.

"It is he! no other!" and it was needless to pronounce the name.

"Yes! it is he! on horseback, and only a hundred paces in advance of his enemies! He is pursued!"

"It is Joe--Joe himself!" cried the doctor, turning pale.

"He cannot see us in his flight!"

"He will see us, though!" said the doctor, lowering the flame of his blow-pipe.

"But how?"

"In five minutes we shall be within fifty feet of the ground, and in fifteen we shall be right over him!"

"We must let him know it by firing a gun!"

"No! he can't turn back to come this way. He's headed off!"

"What shall we do, then?"

"We must wait."

"Wait?--and these Arabs!"

"We shall overtake them. We'll pass them. We are not more than two miles from them, and provided that Joe's horse holds out!"

"Great God!" exclaimed Kennedy, suddenly.

"What is the matter?"

Kennedy had uttered a cry of despair as he saw Joe fling himself to the ground. His horse, evidently exhausted, had just fallen headlong.

"He sees us!" cried the doctor, "and he motions to us, as he gets upon his feet!"

"But the Arabs will overtake him! What is he waiting for? Ah! the brave lad! Huzza!" shouted the sportsman, who could no longer restrain his feelings.

Joe, who had immediately sprung up after his fall, just as one of the swiftest horsemen rushed upon him, bounded like a panther, avoided his assailant by leaping to one side, jumped up behind him on the crupper, seized the Arab by the throat, and, strangling him with his sinewy hands and fingers of steel, flung him on the sand, and continued his headlong flight.

A tremendous howl was heard from the Arabs, but, completely engrossed by the pursuit, they had not taken notice of the balloon, which was now but five hundred paces behind them, and only about thirty feet from the ground. On their part, they were not twenty lengths of their horses from the fugitive.

One of them was very perceptibly gaining on Joe, and was about to pierce him with his lance, when Kennedy, with fixed eye and steady hand, stopped him short with a ball, that hurled him to the earth.

Joe did not even turn his head at the report. Some of the horsemen reined in their barbs, and fell on their faces in the dust as they caught sight of the Victoria; the rest continued their pursuit.

"But what is Joe about?" said Kennedy; "he don't stop!"

"He's doing better than that, Dick! I understand him! He's keeping on in the same direction as the balloon. He relies upon our intelligence. Ah! the noble fellow! We'll carry him off in the very teeth of those Arab rascals! We are not more than two hundred paces from him!"

"What are we to do?" asked Kennedy.

"Lay aside your rifle,Dick."

And the Scot obeyed the request at once.

"Do you think that you can hold one hundred and fifty pounds of ballast in your arms?"

"Ay, more than that!"

"No! That will be enough!"

And the doctor proceeded to pile up bags of sand in Kennedy's arms.

"Hold yourself in readiness in the back part of the car, and be prepared to throw out that ballast at a single effort. But, for your life, don't do so until I give the word!"

"Be easy on that point."

"Otherwise, we should miss Joe, and he would be lost."

"Count upon me!"

The Victoria at that moment almost commanded the troop of horsemen who were still desperately urging their steeds at Joe's heels. The doctor, standing in the front of the car, held the ladder clear, ready to throw it at any moment. Meanwhile, Joe had still maintained the distance between himself and his pursuers--say about fifty feet. The Victoria was now ahead of the party.

"Attention!" exclaimed the doctor to Kennedy.