They readily promised not to do any harm to the box, and as soon as dinner was over they hurried off to the old part of the house, Alan feeling rather flattered by Marjory's suggestion that he might be able to find some way of opening the chest.
There was no sign of any lock except the one in front, which they had tried before, and in which none of the keys would turn. The lid fitted firmly and smoothly, and so tightly that its joining with the box was hardly visible. It was a magnificent specimen of cabinet work.
"Of course it may have a spring," said Marjory, "if only we knew where to find it."
At this suggestion they all set to work to push and thump and press, but as before their efforts were of no avail.
Marjory wondered to herself whether the same ingenious person who had contrived the secret door upstairs might have made this box.
"Suppose we turn it round, and see what the hinges look like," said Alan.
They managed to drag it out from the wall, bringing with it masses of black cobwebs and the dust of many years.
Alan's idea was a good one; but there were no hinges to be seen.
"I believe the lock and the hasps are nothing but false ones to put people off the scent," said Alan. "What a beastly mess," rubbing the cobwebs off his hands on to his knickerbockers. "I believe this is a puzzle chest, and it opens in some secret way like Mrs. Shaw's box. We're having quite a run of secrets."
How Blanche longed to tell Alan of the room upstairs! It was all she could do to prevent herself from speaking of it.
Hot and breathless from their efforts in moving the box, the three sat down to rest and to consult as to their next attempt.
"I don't believe there is a lock at all," Alan repeated, and he began once more to examine the lid of the chest. After some little time he suddenly exclaimed, "I believe I've got it; look here!" He showed the girls that the construction of the lid at two of the corners was slightly different from the other two. "It's something to do with these corners, I'll be bound," he cried excitedly. "Here it comes!"
The girls looked on with intense interest. The big brass nails at the two corners came out, it seemed, and one side of the lid came right off. The row of nails all round the rest of it were long enough to go through the depth of it, and they fitted into corresponding holes in the box itself, so that once the one side was undone the whole thing simply lifted off. It was a most ingenious contrivance, and calculated to baffle even the most clever and curious person.