In the third story, and only accessible by two flights of stairs leading from Arthur’s suite of rooms, was a large square apartment, the door of which Mrs. Johnson unlocked with a mysterious shake of the head, saying to the ladies, “The Lord only knows what this place is for.  Mr. St. Claire must have fixed it himself for I found it locked tighter than a drum, but I accidentally found on the but’ry shelf a rusty old key, that fits it to a T. I’ve been in here once and bein’ you’re his kin,” nodding to Grace, “and t’other one is with you, it can’t do an atom of harm for you to go.  He’s took more pains with this chamber than with all the rest, and when I asked what ’twas for, he said it was his “den,” where he could hide if he wanted to.”

“Don’t go,” whispered Edith, pulling at Grace’s dress, “Mr. St. Claire might not like it.”

But Grace felt no such scruples, and was already across the threshold, leaving Edith by the door.

“It’s as bad to look in as to go in,” thought Edith, and conquering her curiosity with a mighty effort, she walked resolutely down stairs, having seen nothing save that the carpet was of the richest velvet and that the windows had across them slender iron bars, rather ornamental than otherwise, and so arranged as to exclude neither light nor air.

Grace, on the contrary, examined the apartment thoroughly, thinking Mrs. Johnson right when she said that more pains had been taken with this room than with all the others.  The furniture was of the most expensive and elegant kind.  Handsome rosewood easy-chairs and sofas covered with rich satin damask, the color and pattern corresponding with the carpet and curtains.  Ottomans, divans and footstools were scattered about—­pictures and mirrors adorned the walls, while in one corner, covered with a misty veil of lace, hung the portrait of a female in the full, rich bloom of womanhood, her light chestnut curls falling about her uncovered neck, and her dreamy eyes of blue having in them an expression much like that which Edith had once observed in Nina’s peculiar eyes.  The dress was quite old-fashioned, indicating that the picture must have been taken long ago, and while Grace gazed upon it her wonder grew as to whose it was and whence it came.

“Look at the bed,” said Mrs. Johnson, and touching Grace’s elbow, she directed her attention to a side recess, hidden from view by drapery of exquisite lace, and containing a single bed, which might have been intended for an angel, so pure and white it looked with its snowy covering.

“What does it mean?” asked Grace, growing more and more bewildered, while Mrs. Johnson replied in her favorite mode of speech.

“The Lord only knows—­looks as if he was going to make it a prison for some princess; but here’s the queerest thing of all,” and she thumped upon a massive door, which was locked and barred, and beyond which her prying eyes had never looked.

Over the door was a ventilator, and Grace, quite as curious as Mrs. Johnson, suggested that a chair or table be brought, upon which she, being taller than her companion, might stand and possibly obtain a view.