Christy went into his state room, where he kept all his important papers in his desk.

He gave himself up to a consideration of the situation in which he was placed.
He had partly closed the door.

But he had not been in the room half an hour before he heard a knock.
"Come in," said he, supposing the caller was Dave.
The door was pushed open, and Mulgrum came in with his tablet in his hand.

The deaf mute had certainly heard his reply to the knock, for he had heeded it instantly, and he smiled at the manner in which the conspirator had "given himself away." The scullion presented his tablet to the captain with a very deferential bow.
"There is an error in the copy of the letter you gave me--in the extract.

If you will give me the original letter from Mr.Warnock, I will correct the mistake," Christy read on the tablet.