'Well, I can assure you that the Lord of Rantremly who lives in London knows nothing about it. I have been up and about since daylight, taking some rough measurements by stepping off distances. I surmise that the secret room is to the left of this stairway. Probably a whole suite of rooms exists, for there is certainly a stair coinciding with this one, and up that stair at midnight I heard a club-footed man ascend. Either that, or the ghost that has frightened you all, and, as I have said, I believe in the man.'
Here the official made the first sensible remark I had yet heard him utter:—
'If the walls are so thick that a prisoner's cry has not been heard, how could you hear his footsteps, which make much less noise?'
'That is very well put, constable, and when the same thing occurred to me earlier this morning, I began to study the architecture of this castle. In the first place, the entrance hall is double as wide at the big doors as it is near the stairway. If you stand with your back to the front door you will at once wonder why the builders made this curious and unnecessary right angle, narrowing the farther part of the hall to half its width. Then, as you gaze at the stair, and see that marvellous carved oak newel post standing like a monumental column, you guess, if you have any imagination, that the stairway, like the hall, was once double as wide as it is now. We are seeing only half of it, and doubtless we shall find a similar newel post within the hidden room. You must remember, constable, that these secret apartments are no small added chambers. Twice they have sheltered a king.'
The constable's head bent low at the mention of royalty. I saw that his insular prejudice against me and my methods was vanishing, and that he had come to look upon me with greater respect than was shown at first.
'The walls need not be thick to be impenetrable to sound. Two courses of brick, and a space between filled with deafening would do it. The secret apartment has been cut off from the rest of the house since the castle was built, and was not designed by the original architect. The partition was probably built in a hurry to fulfil a pressing need, and it was constructed straight up the middle of the stair, leaving the stout planks intact, each step passing thus, as it were, through the wall. Now, when a man walks up the secret stairway, his footsteps reverberate until one would swear that some unseen person was treading the visible boards on the outside.'
'By Jove!' said the constable, in an awed tone of voice.
'Now, officer, I have here a pickaxe and a crowbar. I propose that we settle the question at once.'
But to this proposal the constable demurred.
'You surely would not break the wall without permission from his lordship in London?'