Ping!
It was the short, sharp, peculiar song of a flying bullet—once heard, always remembered.
Then came the dull thud when the leaden ball beat itself shapeless against the stone wall beside him.
The bullet had passed within an inch of Nick's ribs, and he knew at once that he was now a mark for hidden foes.
Yet there had been no revolver report to suggest their location, and Nick instantly surmised that the ball must have been discharged with an air gun.
He knew that it must have come from some quarter behind him, however. And he knew, too, how to bring his murderous assailants from their secret cover.
As quick as a flash, the instant the ball smote the wall beside him, Nick let go his hold upon the stone coping and dropped into the darkness below the window, falling prostrate upon his back.
As he lay there his hand touched something hot, and he drew it nearer to examine it.
It was the battered chunk of lead which had come within an inch of ending his life.
"They meant business, for sure," he said to himself, while waiting for his quick-witted ruse to operate. "I'm blessed if this affair is not taking on a new and lively interest. I reckon there'll be more doing to-night than I gave Patsy to believe.