The turn of a wheel brought the muzzle to the desired elevation, and in a moment Frank touched a small lever.
That put the piece in operation.
The reports that followed were blended so closely together that they sounded like the ripping of a piece of silk.
And the flying shots fairly whistled.
As that appalling hail of bullets began to fly up at the gunners upon the roof, several fell.
The rest ran for their lives, and the weapon they had been preparing was almost destroyed.
One round was enough.
Frank smiled, and remarked:
“We are rid of them now.”
“Then we are safe?” ventured Zamora.