e. But the bottom did not fly up as
it had done for Betty.

"Say, what magical charm, or 'Open Sesame,' did you use on this?" asked
Allen, after vainly trying. "We can't make it work, Bet."

"I don't know," she answered. "I just simply jabbed it with the ruler,
that's all."

"Well, then, please 'jab' again," pleaded Will.

Obligingly Betty took the piece of wood, and began poking about in the
bottom of the tin box. For some time she was as unsuccessful as the boys
had been.

"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."

"I suppose diamonds are smuggled once in a while; aren't they?" asked
Allen.

"Indeed they are," Will answered. "That's what Uncle Sam has to guard
against more than anything else. They are so easy to hide, and it
doesn't take many of them to represent a whole lot of money. But then
the government has the system down pretty fine, and it isn't often that
anything gets away. You see as soon as any purchase of stones on the
other side is made, word is sent to the officials here--that is, any
purchase of any large amount, such as this."

"Then you don't think those diamonds were smuggled?" asked Allen.

"Not for a minute!" declared Will. "They'r