“Why, doctor, can you light up such darkness as this?”
“Who knows, Joe?”
“Ah! if you can do that, you’re the greatest learned man in the world!”
The doctor kept silent for a few moments; he was thinking. His two companions looked at him with much emotion, for they were greatly excited by the strangeness of the situation. Ferguson at last resumed:
“Here is my plan: We have two hundred pounds of ballast left, since the bags we brought with us are still untouched. I’ll suppose that this prisoner, who is evidently exhausted by suffering, weighs as much as one of us; there will still remain sixty pounds of ballast to throw out, in case we should want to ascend suddenly.”
“How do you expect to manage the balloon?” asked Kennedy.
“This is the idea, Dick: you will admit that if I can get to the prisoner, and throw out a quantity of ballast, equal to his weight, I shall have in nowise altered the equilibrium of the balloon. But, then, if I want to get a rapid ascension, so as to escape these savages, I must employ means more energetic than the cylinder. Well, then, in throwing out this overplus of ballast at a given moment, I am certain to rise with great rapidity.”
“That’s plain enough.”
“Yes; but there is one drawback: it consists in the fact that, in order to descend after that, I should have to part with a quantity of gas proportionate to the surplus ballast that I had thrown out. Now, the gas is precious; but we must not haggle over it when the life of a fellow-creature is at stake.”
“You are right, sir; we must do every thing in our power to save him.”