"That peculiar point astonishes you, does it?" said Ferguson.
"It does, indeed."
"But how long do you think my trip is going to last? Whole months? If so, you are greatly mistaken. Were it to be a long one, we should be lost; we should never get back. But you must know that the distance from Zanzibar to the coast of Senegal is only thirty-five hundred--say four thousand miles. Well, at the rate of two hundred and forty miles every twelve hours, which does not come near the rapidity of our railroad trains, by travelling day and night, it would take only seven days to cross Africa!"
"But then you could see nothing, make no geographical observations, or reconnoitre the face of the country."
"Ah!" replied the doctor, "if I am master of my balloon--if I can ascend and descend at will, I sha
