er chum's ear.

"It's a crazy idea; isn't it?" laughed Ruth. Yet she was serious
again in a moment. "I thought, when Mother Purling spoke of his going
there so much, that maybe he had a reason--a particular reason."

"Phineas told me that Jack Crab was the best pilot on this coast,"
remarked Tom. "He knows every channel, and shoal, and reef from
Westhampton to Cape o' Winds. If there was a landing at Thimble
Island, and any secret place upon it, Jack Crab would be likely to
know of it."

"Can you sail us around the Thimble?" asked Ruth. "That's all we
want."

"I asked Phin before we started. The sea is clear for half a mile and
more all around the Thimble. We can circle it, all right, if the wind
holds this way."

"That's all I expect you to do, Tommy," responded Ruth, quickly.

But they all three eyed the conical-shaped rock very sharply as the
_Jennie S._ drew nearer. They ran between the lighthouse and the Thimble.
The tide, in falling, left the green and slime-covered ledges bare.

"A boat could get into bad quarters there, and easily enough," said
Tom, as they ran past.

But when he tacked and the catboat swung her head seaward, they began
to observe the far side of the Thimble. It was almost circular, and
probably all of a thousand yards in circumference. The waves now ran
up the exposed ledges, hissing and gurgling among the cavities, and
sometimes throwing up spume-like geysers between the boulders.

"A bad rock for any vessel to stub her toe against trying to make
Sokennet Harbor," quoth Tom Cameron. "They say that the wreckers used
to have a false beacon here in the old times. They used to bring a sheep
out here and tie a lantern to its neck. Then, at low tide, they'd
drive the poor sheep over the rocks and the bobbing up and down of the
lantern would look like a riding light on some boat at anchor. Then the
lost vessel would dare run in for an anchorage, too, and she'd be
wrecked. Jack Crab's grandfather was hanged for it. So Phineas told me."

"How awful!" gasped Helen.

But Ruth suddenly seized her hand, exclaiming: "See there! what is it
fluttering on the rock? Look, Tom!"

At the moment the boy could not do so, as he had his hands full with the
tiller and sheet, and his eyes were engaged as well. When he turned to
look again at the Thimble, what had startled Ruth had disappeared.

"There was something white fluttering against the rock. It was down
there, either below high-water mark, or ju