“But my father does not care to go ashore,” interposed the son.  “It is vitally important to him that he find the schooner and join his friends aboard.  In fact, I may add that a very considerable sum in the way of a profitable business deal depends upon his going aboard the schooner.”

“But as that craft isn’t here, how can we put your father aboard?” Mr. Farnum asked.

“We are right in the path that is to be taken by our friends’ yacht,” replied the son.  “Since this is not a naval vessel, and you are not under Government orders, I take it you can as well wait here for two or three hours, if need be.  My father will pay suitably for your time, and the service, if you will consent to wait until the yacht appears.”

“I do not need any pay for extending the ordinary courtesies of the sea to those who have suffered wreck,” replied Mr. Farnum, a bit stiffly.

“Whether you take pay or not, sir, will you wait and put my father aboard the yacht?” demanded the son eagerly.  “A vast interest, believe me, sir, is at stake.”

“Oh, there is a very great stake in this,” cried the older man, tremulously.  “I appeal to you, Mr. Farnum, since that is your name, to help me out in this.  And, if you will accept handsome compensation, I shall be very glad to offer it.”

David Pollard, who had heard some of this talk through the open manhole as he lounged by the wheel, now called down to report:  “There’s some kind of a craft on the northern horizon throwing up searchlight signals.”

“That’s our friends’ yacht—­it must be!” proclaimed the young man, darting forward and resting one hand on the rail of the spiral stairway.  “Now, you see, if you will be good to us, we shall not very long trespass on your patience.”

“A schooner—­a sailing craft—­equipped with a searchlight?” asked Jack, wonderingly.

The son flashed upon the submarine boy a look in which there was something of a scowl, but he explained quickly: 

“The boat has auxiliary power, and a complete electric light plant.  Mr. Farnum, you’ll steam toward that searchlight, won’t you?  I tell you, I am positive it is the boat of our friends.”

“Well, I’ll put you where you want to be, of course,” agreed the boatbuilder, though he spoke with some reluctance, for he realized that some great mystery underlay this whole affair.

“Come up, Benson, and take the wheel,” called Mr. Pollard.  So Jack went up and out on the deck, Eph following him, while Hal went to the engine room to watch more of Grant Andrews’ work there.  Jack threw on the speed wheel, then steered north, while Eph threw the searchlight skyward in the path of the approaching vessel.

Within fifteen minutes the two craft were in sight of each other.  Five minutes later they were within hailing distance.  The other craft was a schooner of some eighty or ninety tons, and was using an auxiliary gasoline engine.