"A fine guard for the diamonds," mocked Will from around the corner of the hall.
"Go to bed—you boys!" commanded Betty.
"I thought I would take the box, too," Mr. Nelson resumed. "It forms one of the clues, and I didn't want anything to happen to that. So I decided to take that, put the diamonds in the secret bottom, and hide all down cellar. Only Grace rather upset my plans."
"I—I'm so sorry," said the thirsty one, contritely.
"Don't you be!" returned Betty. "You're as good as a watch dog. To think of me never waking when papa came in my room."
"I was glad you didn't," he said. "I hoped to have it all go off quietly, and tell you in the morning. But as long as you know it now I might as well proceed. I'll go on down cellar and hide them."
"And don't forget to tell us where you put them," Betty urged. "If you go away in the morning, we'll want to know where to run to get them in case the house does catch fire."
"Oh, don't suggest such a thing!" begged her mother.
Mr. Nelson laughed and went on down cellar, coming back soon to tell the waiting ones that he had found a little niche in the wall, near the chimney, and had put the diamonds in the box there. Then the house quieted down again.
Will and Mr. Nelson left on an early train for Boston, both promising to do all they could to learn the secret of the mysterious package of diamonds.