"I thought you made it fifteen?" he exclaimed, looking at me suspiciously.
"Yes, but I don't suppose we shall keep that up. For the sake of argument I call it thirteen?"
"Well?" cramming his mouth as he spoke.
"In twenty-four hours we shall have run a distance of three hundred and twelve miles."
He nodded.
"Therefore, if we have the luck to keep up this pace of two knots less than we are now actually doing, for fifteen days, we shall have accomplished—let me see."
I drew out a pencil, and commenced a calculation on the back of an old envelope.
"Three hundred and twelve multiplied by fifteen. Five times naught are naught; three naughts and two are ten; add two thousand; we shall have accomplished a distance of four thousand six hundred and eighty miles—that is two thousand six hundred and eighty miles further than we want to go."
He was puzzled (and well he might be) by my fluent figures, but would not appear so.
"I understand," said he.