It must be at one end or the other, or else under the floor." The following morning she measured the dining-room, and what was now known as the housekeeper's room, but which in years gone by had been called the still room; and the following day slipped out of doors as soon as she came downstairs and took the outside measurement of the side of the house, marking on the string the position and width of each window.

She had only now to make a plan and compare the figures.
She found that between the back of the bookcase--for she had taken out a few books to ascertain its depth--and the panel of the dining-room there was a thickness of two feet; but between the library and the housekeeper's room there were fully five feet unaccounted for.
In both were deep old-fashioned fireplaces back to back; and even allowing but six inches between these, the depth there would be accounted for, but on either side of the fireplaces there would be a wide space.

There were certainly no cupboards visible in the library, for the bookcases extended from the fireplace to the wall on each side.

In the housekeeper's room there were cupboards on each side of the chimney-piece, but these were shallow, not being above nine inches in depth; therefore behind these there was a considerable space unaccounted for.

It was evident to Mrs.Conway that her first search must lie in this direction.