"Mind you wake me up if the slightest thing occurs," said the doctor; "and, above all things, keep your eyes upon the barometer. That is our compass."
The night was cold. There were twenty-seven degrees difference between its temperature and that of the day. With darkness rose the nocturnal concert of the animals which hunger and thirst drove from their lairs: the frogs sang their soprano, increased by the yelpings of the jackals, while the basso profundo of the lions sustained the music of this living orchestra.
When he got up in the morning Doctor Ferguson consulted his compass, and perceived that the wind had changed during the night. The "Victoria" had drifted about thirty miles to the northwest in about two hours. It had passed over Mabunguru, a very stony region, strewn with blocks of syenite of a beautiful polish, and dotted with rocks upon the shelving ridges; conical masses, like the pillars of Karnak, stuck up from the ground as high as Druidical "dolmens." Numerous skeletons of buffaloes and elephants lay blanching here and there. There were few trees except in the east, where some villages lay concealed in the midst of deep woods.
About seven o'clock a round rock, nearly two miles in extent, appeared, wearing the appearance of the back of an enormous tortoise.
"We are having a pleasant trip," said Doctor Ferguson. "There is Jihoue-la-Mkoa, where we shall stay for a little time. I must replenish the water-tanks; let us catch hold of something."
"There are very few trees," said Kennedy.
"Let us try, nevertheless. Joe, throw out the grapnels."
The balloon, by degrees, lost its ascending power, and approached the ground, the fluke of one of the grapnels caught in a fissure of a rock, and the "Victoria" halted.
You must not imagine that Doctor Ferguson was able to completely stop the action of the blow-pipe during these halts. The equilibrium of the balloon had been reckoned at the level of the sea; now the country was continually on the ascent, and they were elevated 600 or 700 feet above the sea level, so the balloon had the tendency to descend lower even than the surface of the ground. It was, therefore, necessary to sustain it by a certain expansion of gas.
