In a few moments the hydroplane was alongside.  The yellow hood over her powerful engines glistened with the wet of the great bow-wave her speed had occasioned, and her powerful motor was exhausting with a roar like a battery of machine guns.

Crouched aft of the engine hood was Sam Redding, who held the wheel.  Jack Curtiss and Bill Bender were in the stern.  They sat tandem-wise in the narrow racing shell.

“Want a tow rope for that old stone dray of yours?” jeered Jack Curtiss, as the speedy little racer ranged alongside.

He did not know that the Flying Fish was slowed down, and that although the hydroplane appeared to be capable of tremendous speed, she was not actually so very much faster than Rob’s boat.

“Say, you fellows,” warned Rob, making a trumpet of his hands, “the captain says it’s coming on to blow before long.  You’d better get back into the inlet with that craft of yours.”

“Save your breath to cool your coffee,” shouted Sam Redding back at him, across the fifty feet or so of water that lay between the two boats.  “We know what we are about.”

“But you’re risking your lives,” shouted Merritt.  “That thing wouldn’t live ten minutes in any kind of a sea.”

“Well, we’re not such a bunch of old women as to be scared of a little wetting,” jeered Jack Curtiss.  “So long!  We’ve got no time to wait for that old tub of yours.”

Before the boys could voice any more warnings, the hydroplane, which had been slowed down, dashed off once more.

“I don’t know what we are to do,” spoke up Merritt.  “We can’t compel them to go in, and, after all, the captain may be mistaken.”

“No, I’m not, my son,” rejoined the veteran.  “I can smell wind—­and see them ‘mare’s tails’ in the sky over yonder.  They’re as fall uv wind as a preacher is uv texts.”

“Well, we’ve done our best to warn them,” concluded Rob.  “If they are so foolhardy as to keep on, we can’t help it.”

In half an hour more the boys had landed the captain at the little pier he had built on his island, and to which his rowboat was attached, and were ready to start back, good-bys having been said.

“Hark!” exclaimed the captain, as Rob prepared to give the order to “Go ahead.”

The boys listened, and heard a low, distant moaning sound, something like the deepest rumbling notes of a church organ.

“That’s the wind comin’,” warned the captain.  “Yer’d better be hurryin’ back.”

With more hasty good-bys, the lads got under way at once.  As they emerged from the lee of the island they could see that seaward the ocean was being rapidly lashed into choppy, white—­ crested waves by the advancing storm, and that the wind was freshening into a really stiff breeze.

“Those fellows must be wishing they took our advice now if they are fools enough to have kept out,” said Merritt, as he slowed down the engine so as to permit the Flying Fish to ride the rising seas more easily.