He managed to work himself down until he had a firm grip on the piece of glass under him—a grip that did not cut.
"Now let me figure this out," he mused.
It was obvious that he could not hold the piece of glass in his fingers and saw away at the ropes around his wrists. He could not bend his fingers back far enough.
"If I could only get the glass between my feet, I might be able to bend them back far enough, by lying on my face, so I could saw on the ropes that way," he reflected. He tried, but soon had to give it up. He also endeavored to do this by lying on his side, but it was of no use. Then, in a flash, it came to him.
"I'll bury the glass in the ground, to hold it," he told himself. "By leaving a sharp, jagged edge sticking out I ought to be able to saw through the ropes on my wrists, by rubbing the cords up and down against the glass. I'll do it!"
It was hard work, but by lying on his side Jack managed, after a fashion. He had to work without seeing what he was doing. Even daylight would not have helped him, for he could not see behind his back.
By using the glass as a sort of shovel, Jack managed to dig a hole in the earth. He then put the long piece of glass in this, upright, and packed dirt around it. His fingers came in contact with a small stone, and he used this to tamp the soil and gravel around the glass knife, to hold it more firmly upright. He cut himself several times while doing this, but he kept on.
Finally he was ready to make the attempt. It was more than an hour after he first began his operations, and he was weary, for he had to work in a cramped and uncomfortable position. He rested a few minutes, and then began sawing the rope around his wrists up and down on the sharp piece of glass stuck upright in the ground.
It had to be done slowly and gently, because too much pressure would have overturned the queer knife. Jack knew he must be patient. He cut his wrists more than once, but the gashes were slight, and he thought the bleeding would soon stop.
Finally he felt the bonds loosening slightly. Some of the rope strands were cut through.