ived at the certain conclusion that no living man was within those
walls.

"Would a corpse rise to the surface soon in waters such as these, Dr.
Trendon?" asked the captain.

"Might, sir. Might not. No telling that."

The captain ruminated. Then he beat his fist on his knee.

"The other cave!"

"What other cave?" asked the surgeon.

"The cave where they killed the seals."

"Surely!" exclaimed Trendon. "Wait, though. Didn't Slade say it was
between here and the point?"

"Yes. Beyond the small beach."

"No cave there," declared the surgeon positively.

"There must be. Congdon, did you see an opening anywhere in the cliff as
we came along?"

"No, sir. This is the only one, sir."

"We'll see about that," said the captain, grimly. "Head her about. Skirt
the shore as near the breakers as you safely can."

The gig retraced its journey.

"There's the beach, as Slade described it," said Captain Parkinson, as
they came abreast of the little reach of sand.

"And what are those two bird-roosts on it?" asked Trendon. "See 'em? Dead
against that patch of shore-weed."

"Bits of wreckage fixed in the sand."

"Don't think so, sir. Too well matched."

"We have no time to settle the matter now," said the captain impatiently.
"We must find that cave, if it is to be found."

Hovering just outside the final drag of the surf, under the skilful
guidance of Congdon, the boat moved slowly along the line of beach to the
line of cliff. All was open as the day. The blazing sun picked out each
detail of jut and hollow. Evidently the poisonous vapours from the volcano
had not spread their blight here, for the face of the precipice was bright
with many flowers. So close in moved the boat that its occupants could
even see butterflies fluttering above the bloom. But that which their
eager eyes sought was still denied them. No opening offered in that
smiling cliff-side. Not by so much as would admit a terrier did the mass
of rock and rubble gape.

"And Slade described the cave as big enough to ram the _Wolverine_ into,"
muttered Trendon.

Up to the point of the headland, and back, passed the boat. Blank
disappointment was the result.

"What is your opinion now, Dr. Trendon?" asked the captain of the older
man.

"Don't know, sir," answered the surgeon hopelessly. "Looks as if the cave
might have been a hallucination."

"I shall have something to say to Mr. Slade on our return," said the
captain crisply. "If the cave was an