At this moment the ascensional force of the balloon increased prodigiously, and Ferguson, Kennedy, and Joe, waved a last good-by to their friends. “Let go all!” shouted the doctor, and at the word the _Victoria_ shot rapidly up into the sky, while the four carronades on board the _Resolute_ thundered forth a parting salute in her honor. CHAPTER TWELFTH. Crossing the Strait.—The Mrima.—Dick’s Remark and Joe’s Proposition.—A Recipe for Coffee-making.—The Uzaramo.—The Unfortunate Maizan.—Mount Duthumi.—The Doctor’s Cards.—Night under a Nopal. The air was pure, the wind moderate, and the balloon ascended almost perpendicularly to a height of fifteen hundred feet, as indicated by a depression of two inches in the barometric column. At this height a more decided current carried the balloon toward the southwest. What a magnificent spectacle was then outspread beneath the gaze of the travellers! The island of Zanzibar could be seen in its entire extent, marked out by its deeper color upon a vast planisphere; the fields had the appearance of patterns of different colors, and thick clumps of green indicated the groves and thickets. The inhabitants of the island looked no larger than insects. The huzzaing and shouting were little by little lost in the distance, and only the discharge of the ship’s guns could be heard in the concavity beneath the balloon, as the latter sped on its flight. “How fine that is!” said Joe, breaking silence for the first time. He got no reply. The doctor was busy observing the variations of the barometer and noting down the details of his ascent. Kennedy looked on, and had not eyes enough to take in all that he saw. The rays of the sun coming to the aid of the heating cylinder, the tension of the gas increased, and the _Victoria_ attained the height of twenty-five hundred feet. The _Resolute_ looked like a mere cockle-shell, and the African coast could be distinctly seen in the west marked out by a fringe of foam. “You don’t talk?” said Joe, again. “We are looking!” said the doctor, directing his spy-glass toward the mainland. “For my part, I must talk!” “As much as you please, Joe; talk as much as you like!” And Joe went on alone with a tremendous volley of exclamations. The “ohs!” and the “ahs!” exploded one after the other, incessantly, from his lips. During his passage over the sea the doctor deemed it best to keep at his present elevation. He could thus reconnoitre a greater stretch of the coast. The thermometer and the barometer, hanging up inside of the half-opened awning, were always within sight, and a second barometer suspended outside was to serve during the night watches.