Losing his presence of mind, Jack quitted his hold, and dropped upon the frame.

The plank hung over his head.

A moment more and he would have been crushed beneath the ponderous board, when a slight but strong arm arrested its descent.
"Get from under it, Jack!" vociferated Thames.

"I can't hold it much longer--it'll break my wrist.

Down we come!" he exclaimed, letting go the plank, which fell with a crash, and leaping after Sheppard, who had rolled off the frame.
All this was the work of a minute.
"No bones broken, I hope," said Thames, laughing at Jack, who limped towards the bench, rubbing his shins as he went.
"All right," replied Sheppard, with affected indifference.
"It's a mercy you both escaped!" ejaculated Wood, only just finding his tongue.