"I don't believe I can do it again," she said, puckering her forehead in an attempt to remember. "Let's see, I sat this way, and I held it that way."
"Did you have your fingers crossed?" asked Roy, laughing.
"What had that to do with it?" demanded Betty. But before Roy could answer she uttered a cry, for, as she was moving the ruler about on the bottom of the box, there was that sudden click and spring again, and the false bottom sprang out of the way, disclosing the place where the diamonds had been.
"How did you do it Betty?" asked Allen, and then it was seen that the ruler had pressed on a tiny plate in the corner of the box, a plate so well hidden that only the most careful scrutiny revealed it.
Once it was seen, however, the trick was easy to work. The cover was snapped into place again, and as soon as the ruler, or for that matter, the tip of one's finger, pressed on the little plate, the hiding place was disclosed.
The boys and girls "played" the trick over and over again, until it was an easy matter to do it.
"This is more fun than the cipher," said Allen, taking a copy of it from his pocket.
"Going to have another go at it?" asked Will.
"Yes. It might be a clue to the owner of the diamonds."
"That's so," agreed the other. "I would like to know to whom they belong."