With the departure of the Petrel on her return to the waters near Snipe Point, and with a barely-perceptible rise of wind, the sloop Arrow laid a zigzag course toward the Ten Thousand Islands and came abreast of them about five o’clock.  Beyond a broad inlet that led into the bay, a white sand beach, sparsely overgrown with crabgrass and waving palmettos, indicated to Dave that they were near one of his old camping places.  He called Captain Vinton’s attention to it, hinting that it would be a good place to spend the night.

“Why not aboard the sloop?” queried Vinton, though he knew perfectly well that Dave would seek any excuse to stretch his unseaworthy limbs on terra firma in preference to tossing on the bosom of old ocean.

“Bad weather comin’,—–­windy to-night,” said the Seminole prophet, pointing to a bank of jagged slaty-gray clouds that was rising in the west over the gulf.

“Reckon you’re right, Dave.  If that brings half the wind its looks promise, I’d ruther have these keys between it and us—–­eh?  There’s anuther squall brewin’ out yonder.  Come on, let’s go ashore, lads.”

Making in shoreward, the Arrow presently cast anchor off a shallow cove “inside” the nearest bar.  All five boys got into the sloop’s dory, and after landing the others on the beach, Hugh rowed back to the sloop to bring the captain, Norton and the guide ashore.  When they landed, they discovered Billy and Alec, Chester and Mark engaged in examining a big battered tin box, locked, with its cover sealed up with black sealing wax, which they had found half buried in the sand.

“What is it?  What have you got there?” Hugh asked quickly, running forward.

“It looks like part of Captain Kidd’s buried treasure!” said Billy, whose eyes were sparkling with anticipation.

“Nothing of the sort!” declared matter-of-fact Chester.  “It’s probably a lot of old maps and charts.”

“Let’s open it and see,” was Alec’s advice.

But the captain interposed.

“Let it alone, boys,” he said.  “It’s marked with a small initial ‘B.’  That may stand for Bego or—–­bait.”

CHAPTER III

ON A LONE SCOUT

The captain’s oracular advice mystified the boys until, seated by their evening camp fire of driftwood, he explained to them that the mysterious box might be filled with articles such as Juan Bego and his men were both hiding and collecting.

“I dunno as he’s been as far up the coast as this,” Vinton added, “but ’twouldn’t be hard for a sly old sea-dog like him to creep along these keys at night time ’most any distance.”

“Are we far from the Everglades?” asked Billy, cautiously stirring the fire; for, in spite of the spring warmth, there was a decided chill in the air so close to the ocean.

“Well, the ’Glades are a good stiff hike from here,” replied the captain.  “Eh, Dave; how about it?”