A bullet had entered one of the loopholes and struck the barrel.

It was an unfortunate chance, one in a thousand, and had not Henry's acute ear detected at once the sound of flowing water, it might have proved a terrible loss.
But Henry was rapidly stuffing a piece of buckskin, torn from his hunting shirt, into the little round hole, and he waved Paul back to the wall.
"You stay there and watch, Paul," he said.

"I'll fix this." The buckskin stopped all the flow but a slight drip.

Then, with his strong hunting knife, he cut a piece of wood from the bench, whittled it into shape, and drove it tightly into the bullet hole.
"That's all secure," he said, with a sigh of relief.

"Now I must get it out of range." He wheeled it to a point in the cabin at which no chance bullet could reach it, and then resumed the watch with Paul.
"Aren't you glad, Paul," said Henry, "that you were not in the place of the water barrel ?" "Yes," replied Paul lightly, "because a piece of buckskin and a round stick wouldn't have healed the damage so quickly." He spoke lightly because he was still full of confidence.