The sharp air of the northern winter blew down upon him, and he saw the clear waters of the little rivers, cold as ice, foaming over the stones.

That air was sharp and vital, but, after a while, he came back to himself and closed his book with a sigh.
"Pardon me for inattention, boys," he said, "but while I was enjoying my algebra I was also thinking of old times back there in Vermont, when nobody was shooting at anybody else." Dick and Pennington walked solemnly back and sat down beside him again.
"Returned to his right mind.

Quite sane now," said Pennington.

"But don't you think, Dick, we ought to take that exciting book away from him?
The mind of youth in its tender formative state can be inflamed easily by light literature." Warner smiled and put his beloved book in his pocket.
"No, boys," he said, "you won't take it away from me, but as soon as this war is over I shall advance from it to studies of a somewhat similar nature, but much higher in character, and so difficult that solving them will afford a pleasure keener and more penetrating than anything else I know." "What is your greatest ambition, Warner ?" asked Pennington.

"Do you, like all the rest of us, want to be President of the United States ?" "Not for a moment.