went deeper. She was like an otter in the water,
and having stuffed her ears with cotton she felt prepared to remain
below a long time.

Once she had opened her eyes while diving with Bess, and she thought she
saw a shadowy something on the bottom of the lake that was neither a
boulder nor a waterlogged snag.

She beat her way to the bottom as rapidly as possible; but the light did
not follow her. She could see nothing when she opened her eyes. It
seemed as though something overshadowed her.

The water was tugging at her; she could not remain below for long. But
as she turned to drift up again, her shoulder touched something. She
struck out and reached it. But the blow really pushed her away and she
floated upward toward the surface.

When she paddled to the raft she was panting, and Frank demanded:

"What's the matter, Wyn? You look as if you'd seen a ghost I believe you
stay down too long."

"No," gasped Wyn. "I--I hit something."

"What was it?"

"Why--why, it looked like a wagon. 'Twas something."

"I suppose so!" laughed Frank. "Wagon with a load of hay on it--eh?"

Wyn said nothing more. She sat upon the float, with her knees drawn up
and hugged in her brown arms, and thought. The other girls could get
nothing out of her.

She wasn't dreaming, however. She was thinking to a serious purpose.

It _had_ looked like a wagon--as much as it looked like anything
else. But, of course, she had seen it very dimly. She knew by the touch
that it was of wood; but it was no waterlogged tree, although there was
slime upon it It was not rough; but smooth.

Of course, it wasn't a wagon. Nor was it a huge box. Neither wagon nor
box could have got out here, fifteen or twenty rods off Gannet Island.

Wyn glanced over toward the island and saw that she could look right
into the cove where John Jarley had met with his accident. According to
the boatman's story, as he went overboard from the motor boat he gave
the wheel a twist that should have shot her directly out of the cove
toward the middle of the lake.

"But suppose the boat didn't respond, after all, to the twist of the
wheel?" Wyn was thinking. "Or, suppose the slant of the rudder was not
as great as he supposed?"

She fixed in her mind about the spot where the thing lay she had hit,
and then glanced back to the tree on the bank of the cove, that showed
the long scar where the branch was torn off.

The line between the two was clear. The motor boat might hav