"They're not on the island," asserted Cassidy. "We've combed it from end to end, an' we're ready to swear there ain't a livin' soul on the island but us three."
"It couldn't be that a boat has put in and taken them off, Cassidy," went on Matt. "No boat would have had time to do that. You'll certainly find them on the island if you look sharp."
Cassidy and his mates took another turn about the island, but with no better success. Jurgens and Whistler had mysteriously disappeared.
Giving up trying to locate the missing scoundrels, Matt had Cassidy, Burke and Harris tote the various parts of the air ship out to the Grampus. Some of the parts were loaded inside the boat, and the rest—too large to come down the hatch in the conning tower—were roped to the rounded deck.
This method of loading made it necessary for the Grampus to keep on the surface of the water all the way to Palm Beach. Matt, however, had another plan in mind before going to Palm Beach, and as soon as the Hawk had been safely loaded he had a talk with Cassidy in the periscope room and led up to his plan. The result was another surprise for the three chums—one that was well-nigh overwhelming.
"I suppose you know, Cassidy," observed Matt, "why Jurgens stole the Grampus?"
Cassidy cocked up his eyes shrewdly at Matt.
"I know," said he, "but I don't reckon any one else does, exceptin' Cap'n Nemo, Jr., hisself."
"That's where you're mistaken, Cassidy," returned Matt. "Captain Nemo, Jr., or Mr. Townsend, as we have come to call him, told me and my pards all about it."
"Then I reckon that's the fust time he ever let the thing out."