“Oh, I’ll look it over, if that’s all you want,” said Nat, who, truth to tell, had rather a hankering to inspect the piece of machinery that could force a boat through the water at the pace that old Harley’s was driven. “I won’t guarantee to be able to remedy the trouble, though.”

“That’s all right, lad; jes look at it, an’ if you can’t fix it I’ll hev to ask you fellows for a tow into Santa Barbara, I reckon, fer we’re plumb busted down now.”

Nothing could have appeared more open and above board than this. Nat, without hesitation, stooped to crawl in under the whaleback hood that protected the motor from spray.

As he stooped he heard a sudden shout from above.

“Look out, Nat!”

But it was too late. The boy was felled by a terrific blow from behind. All the world went red about him and then faded into blackness amidst which a humming noise like that of a speeding motor rang vibrantly.

CHAPTER XIV.

NAT A PRISONER.

“Is he coming round, Seth?”

These words in old Israel’s voice were Nat’s next conscious impression. They were coupled with the dousing in his face of a bucket of sea water.