"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 commonwealth."
"Go on!" laughed Henry Blackford. "You'll be saying next that it's smugglers' booty, and you'll be asking us to pay a duty on it. Let's open the box and see what it is—maybe nothing but seaweed. I've heard of jokes being played before," and he looked at the girls meaningly.
"Oh, we didn't hide it and then find it again," Amy assured him, so earnestly that the others laughed.
"Well, here goes for a try, anyhow," said Mr. Nelson.
With a bunch of assorted keys he tried one after another in the strange lock. Some keys would not even enter the aperture, while others turned uselessly around in it.
Betty's father used all he had without success, and then the boys were called on. They were not able to produce the Sesame to the japanned box, and Will's plan of using an axe was finding more favor when Allen produced a small key of peculiar make.
"Try this," he said. "It locks the switch on the motor boat, but it may fit. It looks as though it would."