"It will make a nice jewel casket," put in Tom. "When you settle down with Dora, you can give if to her for her dia——"
"Oh, stow that, Tom! If Dora ever does take me for a husband, it won't be for some years to come, you must know that."
"Let me take a look at the box," put in Sam. "I never got the chance to look it over carefully."
"It's odd that they should engrave it inside," went on Dick. "Especially since the outside silver corners are plain."
"Perhaps there is a secret spring hidden by the engraving," suggested Tom. "Hunt around. It may fly apart and let out a hundred thousand in diamonds."
"Don't be foolish, Tom," said Dick. "It isn't likely there is a spring."
"But there just is a spring!" exclaimed Sam, who was handling the box. "Hark!"
He ran his finger nail over a spot on one side of the box, and there followed a tiny click. Then he ran his finger nail back, and there was another click.
"Hurrah! Sam has solved the mystery of the sphinx!" cried Tom. "Can you open it? I claim a third share of the diamonds!"
"Give me the box," said Dick, also a bit excited. When he got it in his hands he, too, ran his finger nail over the engraved brass. Several tiny clicks followed.