“I exaggerate nothing,” continued Ferguson, “for, upon reading the narratives of such travellers as have had the hardihood to venture into these regions, your eyes would fill with tears.” About eleven o’clock they were passing over the basin of Imenge, and the tribes scattered over the adjacent hills were impotently menacing the _Victoria_ with their weapons. Finally, she sped along as far as the last undulations of the country which precede Rubeho. These form the last and loftiest chain of the mountains of Usagara. The aëronauts took careful and complete note of the orographic conformation of the country. The three ramifications mentioned, of which the Duthumi forms the first link, are separated by immense longitudinal plains. These elevated summits consist of rounded cones, between which the soil is bestrewn with erratic blocks of stone and gravelly bowlders. The most abrupt declivity of these mountains confronts the Zanzibar coast, but the western slopes are merely inclined planes. The depressions in the soil are covered with a black, rich loam, on which there is a vigorous vegetation. Various water-courses filter through, toward the east, and work their way onward to flow into the Kingani, in the midst of gigantic clumps of sycamore, tamarind, calabash, and palmyra trees. “Attention!” said Dr. Ferguson. “We are approaching Rubeho, the name of which signifies, in the language of the country, the ‘Passage of the Winds,’ and we would do well to double its jagged pinnacles at a certain height. If my chart be exact, we are going to ascend to an elevation of five thousand feet.” “Shall we often have occasion to reach those far upper belts of the atmosphere?” “Very seldom: the height of the African mountains appears to be quite moderate compared with that of the European and Asiatic ranges; but, in any case, our good _Victoria_ will find no difficulty in passing over them.” In a very little while, the gas expanded under the action of the heat, and the balloon took a very decided ascensional movement. Besides, the dilation of the hydrogen involved no danger, and only three-fourths of the vast capacity of the balloon was filled when the barometer, by a depression of eight inches, announced an elevation of six thousand feet. “Shall we go this high very long?” asked Joe. “The atmosphere of the earth has a height of six thousand fathoms,” said the doctor; “and, with a very large balloon, one might go far. That is what Messrs. Brioschi and Gay-Lussac did; but then the blood burst from their mouths and ears. Respirable air was wanting. Some years ago, two fearless Frenchmen, Messrs. Barral and Bixio, also ventured into the very lofty regions; but their balloon burst—” “And they fell?” asked Kennedy, abruptly. “Certainly they did; but as learned men should always fall—namely, without hurting themselves.”