The country was evidently habitable and inhabited. Troops of hippopotami could be seen disporting themselves in the forests of reeds, or plunging beneath the whitish waters of the lake.

The latter, seen from above, presented, toward the west, so broad an horizon that it might have been called a sea; the distance between the two shores is so great that communication cannot be established, and storms are frequent and violent, for the winds sweep with fury over this elevated and unsheltered basin.

The doctor experienced some difficulty in guiding his course; he was afraid of being carried toward the east, but, fortunately, a current bore him directly toward the north, and at six o'clock in the evening the balloon alighted on a small desert island in thirty minutes south latitude, and thirty-two degrees fifty-two minutes east longitude, about twenty miles from the shore.

The travellers succeeded in making fast to a tree, and, the wind having fallen calm toward evening, they remained quietly at anchor. They dared not dream of taking the ground, since here, as on the shores of the Uyanza, legions of mosquitoes covered the soil in dense clouds. Joe even came back, from securing the anchor in the tree, speckled with bites, but he kept his temper, because he found it quite the natural thing for mosquitoes to treat him as they had done.

Nevertheless, the doctor, who was less of an optimist, let out as much rope as he could, so as to escape these pitiless insects, that began to rise toward him with a threatening hum.

The doctor ascertained the height of the lake above the level of the sea, as it had been determined by Captain Speke, say three thousand seven hundred and fifty feet.

"Here we are, then, on an island!" said Joe, scratching as though he'd tear his nails out.

"We could make the tour of it in a jiffy," added Kennedy, "and, excepting these confounded mosquitoes, there's not a living being to be seen on it."

"The islands with which the lake is dotted," replied the doctor, "are nothing, after all, but the tops of submerged hills; but we are lucky to have found a retreat among them, for the shores of the lake are inhabited by ferocious tribes. Take your sleep, then, since Providence has granted us a tranquil night."

"Won't you do the same, doctor?"

"No, I could not close my eyes. My thoughts would banish sleep. To-morrow, my friends, should the wind prove favorable, we shall go due north, and we shall, perhaps, discover the sources of the Nile, that grand secret which has so long remained impenetrable. Near as we are to the sources of the renowned river, I could not sleep."

Kennedy and Joe, whom scientific speculations failed to disturb to that extent, were not long in falling into sound slumber, while the doctor held his post.

On Wednesday, April 23d, the balloon started at four o'clock in the morning, with a grayish sky overhead; night was slow in quitting the surface of the lake, which was enveloped in a dense fog, but presently a violent breeze scattered all the mists, and, after the balloon had been swung to and fro for a moment, in opposite directions, it at length veered in a straight line toward the north.

Dr. Ferguson fairly clapped his hands for joy.

"We are on the right track!" he exclaimed. "To-day or never we shall see the Nile! Look, my friends, we are crossing the equator! We are entering our own hemisphere!"

"Ah!" said Joe, "do you think, doctor, that the equator passes here?"

"Just here, my boy!"

"Well, then, with all respect to you, sir, it seems to me that this is the very time to moisten it."

"Good!" said the doctor, laughing. "Let us have a glass of punch. You have a way of comprehending cosmography that is any thing but dull."

And thus was the passage of the Victoria over the equator duly celebrated.

The balloon made rapid headway. In the west could be seen a low and but slightly-diversified coast, and, farther away in the background, the elevated plains of the Uganda and the Usoga. At length, the rapidity of the wind became excessive, approaching thirty miles per hour.