“And why?”
“Because it will be trying to solve the problem called ‘the problem of the three bodies,’ for which the integral calculus is not yet far enough advanced.”
“Then,” said Michel Ardan, in his sly tone, “mathematics have not said their last word?”
“Certainly not,” replied Barbicane.
“Well, perhaps the Selenites have carried the integral calculus farther than you have; and, by the bye, what is this ‘integral calculus?’”
“It is a calculation the converse of the differential,” replied Barbicane seriously.
“Much obliged; it is all very clear, no doubt.”
“And now,” continued Barbicane, “a slip of paper and a bit of pencil, and before a half-hour is over I will have found the required formula.”
Half an hour had not elapsed before Barbicane, raising his head, showed Michel Ardan a page covered with algebraical signs, in which the general formula for the solution was contained.
“Well, and does Nicholl understand what that means?”