"Here's the door.

This is the way the old thief brings in all his heavy plunder, which he stows in out-of-the-way holes in his infernal dwelling.

I've seen him often do it." While making these remarks, Blueskin contrived, by means of a chisel which he chanced to have about him, to lift up the board, and, introducing his fingers beneath it, with Jack's assistance speedily opened it altogether, disclosing a dark hole, into which he leapt.
"Follow me, Thames," cried Jack, dropping into the chasm.
They were now in a sort of cellar, at one end of which was a door.

It was fastened inside.

But, taking the chisel from Blueskin, Jack quickly forced back the bolt.
As they entered the room beyond, a fierce growl was heard.
"Let me go first," said Blueskin; "the dogs know me.