“I fixed up Atley’s old short-wave radio, in the old house—and I’ve been getting dope from the yacht the last couple of nights. In about an hour we’ll take off, fly out beyond the lighthouse and patrol.”

“Will you have enough gas?” Larry inquired.

“Had some delivered in cans early this morning—down at the boathouse,” Jeff told him. “We can fill up the main tank and get a reserve in my small wing-tanks—enough for ten hours altogether.”

“Let’s get busy!” urged Sandy.

The three comrades were busy from then on.

Only when Jeff was warming up the engine, checking carefully on his instruments, taking every precaution against any predictable failure, was there time for a moment together and alone.

“Now what do you think of your suspicions?” Dick demanded. Sandy shook his head.

“Most of the time I think I was letting imaginitis get the best of me—but every once in awhile I wonder—for one thing, why doesn’t the yacht sail right on to the New York wharf and let the captain take those emeralds to safe deposit?”

“Golly-to-goodness, you’re right, at that!” Larry nodded his head.

“For another thing,” Sandy went on, “anybody could write that letter Jeff showed me—and who is Jeff, when all is said and done?”