“You fool!” cried Trendon.  “Stand back, all of you.”

Opening his medicine case, he bent over the racked sufferer.  Presently the man sat up, pale and abashed.

“That’s how poisonous volcanic gas is,” said the surgeon to his commanding officer.  “Only inhaled remnants of the dust, too.”

“An ill outlook for the man we’re seeking,” the captain mused.

“Dead if he’s anywhere on this highland,” declared Trendon.  “Let’s look at his flag-pole.”

He examined the staff.  “Came from the beach,” he pronounced.  “Waterworn.  H’m!  Maybe he ain’t so dead, either.”

“I don’t quite follow you, Dr. Trendon.”

“Why, I guess our man has figured this thing all out.  Brought this pole up from the beach to plant it here.  Why?  Because this was the best observation point.  No good as a permanent residence, though.  Planted his flag and went back.”

“Why didn’t we see him on the beach, then?”

“Did you notice a cave around to the north?  Good refuge in case of fumes.”

“It’s worth trying,” said the captain, putting up his glass.

“Hold on, sir.  What’s this?  Here’s something.  Look here.”

Trendon pointed to a small bit of wood rather neatly carved to the shape of an indicatory finger, and lashed to the staff, at the height of a man’s face.  The others clustered around.

“Oh, the devil!” cried Trendon.  “It must have got twisted.  It’s pointing straight down.”

“Strange performance,” said the captain.  “However, since it points that way—­heave aside those rocks, men.”

The first slab lifted brought to light a corner of cardboard.  This, on closer examination, proved to be the cover of a book.  The rocks rolled right and left, and as the flag-staff, deprived of its support, tottered and fell, the trove was dragged forth and handed to the captain.  While the ground jarred with occasional tremors and the mountain puffed forth its vaporous threats, he and the surgeon, seated on a rock, gave themselves with complete absorption to the reading.

III

THE CACHE

Outwardly the book accorded ill with its surroundings.  In that place of desolation and death, it typified the petty neatness of office processes.  Properly placed, it should have been found on a desk, with pens, rulers, and other paraphernalia forming exact angles or parallels to it.  It was a quarto, bound in marbled paper, with black leather over the hinges.  No external label suggested its ownership or uses, but through one corner, blackened and formidable in its contrast to the peaceful purposes of the volume, a hole had been bored.  The agency of perforation was obvious.  A bullet had made it.

“Seen something of life, I reckon,” said Trendon, as the captain turned the volume about slowly in his hands.

“And of death,” returned Captain Parkinson solemnly.  “Do you know, Trendon, I almost dread to open this.”