It had sunk during the night. In its place, the watery immensity of Lake Tchad!

"A poor country for the land-owners!" said Joe, once more vigorously resorting to his skill in the art of natation.

One of those phenomena, which are by no means unusual on Lake Tchad, had liberated our brave Joe. More than one island, that previously seemed to have the solidity of rock, has been submerged in this way; and the people living along the shores of the mainland have had to pick up the unfortunate survivors of these terrible catastrophes.

Joe knew nothing about this peculiarity of the region, but he was none the less ready to profit by it. He caught sight of a boat drifting about, without occupants, and was soon aboard of it. He found it to be but the trunk of a tree rudely hollowed out; but there were a couple of paddles in it, and Joe, availing himself of a rapid current, allowed his craft to float along.

"But let us see where we are," he said. "The polar-star there, that does its work honorably in pointing out the direction due north to everybody else, will, most likely, do me that service."

He discovered, with satisfaction, that the current was taking him toward the northern shore of the lake, and he allowed himself to glide with it. About two o'clock in the morning he disembarked upon a promontory covered with prickly reeds, that proved very provoking and inconvenient even to a philosopher like him; but a tree grew there expressly to offer him a bed among its branches, and Joe climbed up into it for greater security, and there, without sleeping much, however, awaited the dawn of day.

When morning had come with that suddenness which is peculiar to the equatorial regions, Joe cast a glance at the tree which had sheltered him during the last few hours, and beheld a sight that chilled the marrow in his bones. The branches of the tree were literally covered with snakes and chameleons! The foliage actually was hidden beneath their coils, so that the beholder might have fancied that he saw before him a new kind of tree that bore reptiles for its leaves and fruit. And all this horrible living mass writhed and twisted in the first rays of the morning sun! Joe experienced a keen sensation or terror mingled with disgust, as he looked at it, and he leaped precipitately from the tree amid the hissings of these new and unwelcome bedfellows.

"Now, there's something that I would never have believed!" said he.

He was not aware that Dr. Vogel's last letters had made known this singular feature of the shores of Lake Tchad, where reptiles are more numerous than in any other part of the world. But after what he had just seen, Joe determined to be more circumspect for the future; and, taking his bearings by the sun, he set off afoot toward the northeast, avoiding with the utmost care cabins, huts, hovels, and dens of every description, that might serve in any manner as a shelter for human beings.

How often his gaze was turned upward to the sky! He hoped to catch a glimpse, each time, of the Victoria; and, although he looked vainly during all that long, fatiguing day of sore foot-travel, his confident reliance on his master remained undiminished. Great energy of character was needed to enable him thus to sustain the situation with philosophy. Hunger conspired with fatigue to crush him, for a man's system is not greatly restored and fortified by a diet of roots, the pith of plants, such as the Mele, or the fruit of the doum palm-tree; and yet, according to his own calculations, Joe was enabled to push on about twenty miles to the westward.

His body bore in scores of places the marks of the thorns with which the lake-reeds, the acacias, the mimosas, and other wild shrubbery through which he had to force his way, are thickly studded; and his torn and bleeding feet rendered walking both painful and difficult. But at length he managed to react against all these sufferings; and when evening came again, he resolved to pass the night on the shores of Lake Tchad.

There he had to endure the bites of myriads of insects --gnats, mosquitoes, ants half an inch long, literally covered the ground; and, in less than two hours, Joe had not a rag remaining of the garments that had covered him, the insects having devoured them! It was a terrible night, that did not yield our exhausted traveller an hour of sleep. During all this time the wild-boars and native buffaloes, reenforced by the ajoub--a very dangerous species of lamantine --carried on their ferocious revels in the bushes and under the waters of the lake, filling the night with a hideous concert.