The impossibility of crossing this gulf was self-evident, and Kennedy could not restrain a gesture of despair.

But Dr. Ferguson, with an energetic accent of undaunted daring, exclaimed--

"All is not over!"

"I knew it," said Joe, with that confidence in his master which nothing could ever shake.

The sight of the dried-up grass had inspired the doctor with a bold idea. It was the last chance of escape. He led his friends quickly back to where they had left the covering of the balloon.

"We have at least an hour's start of those banditti," said he; "let us lose no time, my friends; gather a quantity of this dried grass; I want a hundred pounds of it, at least."

"For what purpose?" asked Kennedy, surprised.

"I have no more gas; well, I'll cross the river with hot air!"

"Ah, doctor," exclaimed Kennedy, "you are, indeed, a great man!"

Joe and Kennedy at once went to work, and soon had an immense pile of dried grass heaped up near the baobab.

In the mean time, the doctor had enlarged the orifice of the balloon by cutting it open at the lower end. He then was very careful to expel the last remnant of hydrogen through the valve, after which he heaped up a quantity of grass under the balloon, and set fire to it.

It takes but a little while to inflate a balloon with hot air. A head of one hundred and eighty degrees is sufficient to diminish the weight of the air it contains to the extent of one-half, by rarefying it. Thus, the Victoria quickly began to assume a more rounded form. There was no lack of grass; the fire was kept in full blast by the doctor's assiduous efforts, and the balloon grew fuller every instant.

It was then a quarter to four o'clock.

At this moment the band of Talabas reappeared about two miles to the northward, and the three friends could hear their cries, and the clatter of their horses galloping at full speed.

"In twenty minutes they will be here!" said Kennedy.

"More grass! more grass, Joe! In ten minutes we shall have her full of hot air."

"Here it is, doctor!"

The Victoria was now two-thirds inflated.

"Come, my friends, let us take hold of the network, as we did before."

"All right!" they answered together.

In about ten minutes a few jerking motions by the balloon indicated that it was disposed to start again. The Talabas were approaching. They were hardly five hundred paces away.

"Hold on fast!" cried Ferguson.

"Have no fear, master--have no fear!"

And the doctor, with his foot pushed another heap of grass upon the fire.

With this the balloon, now completely inflated by the increased temperature, moved away, sweeping the branches of the baobab in her flight.

"We're off!" shouted Joe.

A volley of musketry responded to his exclamation. A bullet even ploughed his shoulder; but Kennedy, leaning over, and discharging his rifle with one hand, brought another of the enemy to the ground.

Cries of fury exceeding all description hailed the departure of the balloon, which had at once ascended nearly eight hundred feet. A swift current caught and swept it along with the most alarming oscillations, while the intrepid doctor and his friends saw the gulf of the cataracts yawning below them.

Ten minutes later, and without having exchanged a word, they descended gradually toward the other bank of the river.

There, astonished, speechless, terrified, stood a group of men clad in the French uniform. Judge of their amazement when they saw the balloon rise from the right bank of the river. They had well-nigh taken it for some celestial phenomenon, but their officers, a lieutenant of marines and a naval ensign, having seen mention made of Dr. Ferguson's daring expedition, in the European papers, quickly explained the real state of the case.

The balloon, losing its inflation little by little, settled with the daring travellers still clinging to its network; but it was doubtful whether it would reach the land. At once some of the brave Frenchmen rushed into the water and caught the three aeronauts in their arms just as the Victoria fell at the distance of a few fathoms from the left bank of the Senegal.

"Dr. Ferguson!" exclaimed the lieutenant.

"The same, sir," replied the doctor, quietly, "and his two friends."

The Frenchmen escorted our travellers from the river, while the balloon, half-empty, and borne away by a swift current, sped on, to plunge, like a huge bubble, headlong with the waters of the Senegal, into the cataracts of Gouina.

"The poor Victoria!" was Joe's farewell remark.

The doctor could not restrain a tear, and extending his hands his two friends wrung them silently with that deep emotion which requires no spoken words.