At any rate he determined to live as long as he could; and he kept up his spirits by singing scraps of old songs, and his strength by such gymnastic exercises as he could carry out without the aid of any movable article.

At first he struck out his arms as if fighting, so many hundred of times; then he took to walking on his hands; and at last he loosened one of the stones which formed the top of the bed, and invented all sorts of exercises with it.
"What is the day and month ?" he said one day to his gaoler.
"It is the 15th of October." "It is very dark," Rupert said, "darker than usual." "It is raining," the jailer said; "raining tremendously." Late that night Rupert was awoke by the splashing of water.

He leaped to his feet.

The cell was already a foot deep in water.
"Ha!" he exclaimed, "it is one thing or the other now." Rupert had been hoping for a flood; it might bring death, but he thought that it was possible that it might bring deliverance.
The top of the loophole was some two and a half feet from the vaulted roof; the top of the door was about on the same level, or some six inches lower.

The roof arched some three feet above the point whence it sprang.
Rupert had thought it all over, and concluded that it was possible, nay almost certain, that even should the water outside rise ten feet above the level of his roof, sufficient air would be pent up there to prevent the water from rising inside, and to supply him with sufficient to breathe for many hours.