Gripping the keg by the chimes, he hurled it with all of his strength against one of the walls.
There was a double effect.
First, the keg snapped and cracked loudly, as several of the staves yielded under the terrific blow.
Second, an instant later, a bit of rock from the wall fell with a splash into the pool of water.
Nick then examined the wall.
He found that the constant leakage from above had softened the old cement and mortar, and that the stones in this locality might be removed with almost any stout implement.
In half a minute he had the beer-keg demolished and one of the stout staves in his hand.
With this he next attacked the stonework near the pool, and for ten minutes he worked as vigorously and rapidly as the darkness permitted.
Then he had two of the lower stones hauled out of the wall, and a space made large enough to crawl through.