is in it. But I'm not so
sure those men in the boat left it, and if they demand it don't you give
it up to them."

"Oh, I should say not!" cried Mollie, bristling a bit. "_We_ found the
box. They'll have to prove ownership."

Betty tucked the box under her arm. No one disputed her right to carry
it, for the other girls deferred to the Little Captain in matters of
this sort.

"Won't the boys be surprised when they see it!" commented Amy.

"But listen!" cautioned Betty. "We mustn't pretend that we think there
is anything in it. If we do, and there isn't, they'd have the laugh on
us."

"Oh, of course," assented Grace. "We'll just say we found the box on the
beach, and couldn't open it. The boys will be anxious enough to do
that."

And, sure enough, when the girls reached the cottage, the boys being not
far behind them, the latter were even more eager than Betty and her
chums to have a look inside the mysterious iron case.

"Pry the cover off!" cried Will, when he and the others had briefly
related their experience in saving their motor boat and sailing back in
the other craft, while the girls gave their story bit by bit, from the
sighting of the men in the boat, to the finding of the box. Only Betty
said nothing about the faces at the window of the fisherman's hut.

"Pry the cover off!" cried Will. "An axe is the best thing to use!"

"Indeed not!" exclaimed Betty. "Let's see if we can't open it with a
key. You have some odd ones; haven't you, Daddy?"

"Yes," assented Mr. Nelson, who was down at the shore for the week-end.
"Betty, get them. You'll find them in that desk in the living room."

Betty's father had looked at the box on all sides, had shaken it, and
had examined the lock through a reading glass.

"It sure is a find, all right!" declared Roy Anderson. "I wish I had
been with you."

"Oh, if it's a treasure-trove, we'll all share, as they did in Treasure
Island," declared Betty, who was almost a boy in her liking for
adventure stories.

"Ahem!" exclaimed Allen Washburn, with an elaborate assumption of
dignity. "Treasure, you know, is subject to the claim of the
commonwealth, if the lawful heirs cannot be located. I must look up the
law on that subject."

"More likely it's the spoil of pirates, and fair booty for whoever finds
it!" declared Will. "I think I'm the proper one to take charge of this,
representing as I do the United States Government, which takes
precedence over any State commonwealt