A Throng of People on the Horizon.--A Troop of Arabs.--The Pursuit. --It is He.--Fall from Horseback.--The Strangled Arab.--A Ball from Kennedy.--Adroit Manoeuvres.--Caught up flying.--Joe saved at last.

From the moment when Kennedy resumed his post of observation in the front of the car, he had not ceased to watch the horizon with his utmost attention.

After the lapse of some time he turned toward the doctor and said:

"If I am not greatly mistaken I can see, off yonder in the distance, a throng of men or animals moving. It is impossible to make them out yet, but I observe that they are in violent motion, for they are raising a great cloud of dust."

"May it not be another contrary breeze?" said the doctor, "another whirlwind coming to drive us back northward again?" and while speaking he stood up to examine the horizon.

"I think not, Samuel; it is a troop of gazelles or of wild oxen."

"Perhaps so, Dick; but yon throng is some nine or ten miles from us at least, and on my part, even with the glass, I can make nothing of it!"

"At all events I shall not lose sight of it. There is something remarkable about it that excites my curiosity. Sometimes it looks like a body of cavalry manoeuvring. Ah! I was not mistaken. It is, indeed, a squadron of horsemen. Look--look there!"

The doctor eyed the group with great attention, and, after a moment's pause, remarked:

"I believe that you are right. It is a detachment of Arabs or Tibbous, and they are galloping in the same direction with us, as though in flight, but we are going faster than they, and we are rapidly gaining on them. In half an hour we shall be near enough to see them and know what they are."

Kennedy had again lifted his glass and was attentively scrutinizing them. Meanwhile the crowd of horsemen was becoming more distinctly visible, and a few were seen to detach themselves from the main body.

"It is some hunting manoeuvre, evidently," said Kennedy. "Those fellows seem to be in pursuit of something. I would like to know what they are about."

"Patience, Dick! In a little while we shall overtake them, if they continue on the same route. We are going at the rate of twenty miles per hour, and no horse can keep up with that."

Kennedy again raised his glass, and a few minutes later he exclaimed:

"They are Arabs, galloping at the top of their speed; I can make them out distinctly. They are about fifty in number. I can see their bournouses puffed out by the wind. It is some cavalry exercise that they are going through. Their chief is a hundred paces ahead of them and they are rushing after him at headlong speed."

"Whoever they may be, Dick, they are not to be feared, and then, if necessary, we can go higher."

"Wait, doctor--wait a little!"

"It's curious," said Kennedy again, after a brief pause, "but there's something going on that I can't exactly explain. By the efforts they make, and the irregularity of their line, I should fancy that those Arabs are pursuing some one, instead of following."

"Are you certain of that, Dick?"

"Oh! yes, it's clear enough now. I am right! It is a pursuit--a hunt--but a man-hunt! That is not their chief riding ahead of them, but a fugitive."

"A fugitive!" exclaimed the doctor, growing more and more interested.

"Yes!"

"Don't lose sight of him, and let us wait!"

Three or four miles more were quickly gained upon these horsemen, who nevertheless were dashing onward with incredible speed.

"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 t............