"Open that door at once, you young varmints!"
"I'll break every bone in your bodies when I get hold of you," roared Walstein.
"Let 'em rave," grinned Sandy; "that door will withstand a siege."
"If it's anything like that one upstairs, it will," laughed Jack.
The lad felt a strange exhilaration. The feeling was born of the sense of his wits and his chum's being pitted against those of the ruffians outside. So far, the lads had won out unmistakably.
Walstein began to shout and bellow and pound on the door, using all sorts of bad language.
"Don't swear," shouted Sandy. "It won't do you any good. We're in here, and here we'll stay."
"Oh, you will, will you?" struck in another voice. It was that of Barkentin. "We'll see about that."
He gave a peculiar whistle. It rang shrill and clear through the night. The two dogs, on watch in the upper part of the tower, heard it. One of them gave an answering bark.
"After 'em, Rex! Sic 'em, Cæsar!" came Barkentin's voice.