“Willingly!” assented Miss Belcher, holding out her glass to be replenished; “and the more so because I never drank better Rhone wine in my life.”

Dr. Beauregard stood up and bowed, his fine features overspread with a flush of pleased astonishment.

“Madam—­” began Dr. Beauregard, and I have no doubt he had a compliment on his lips.  But at that moment the hills and the amphitheatre of cliff behind us, rang out—­rang out and echoed—­with two terrible screams.

CHAPTER XXXI.

AARON GLASS.

The second scream followed the first almost before we could lift our faces to the cliff.  Dr. Beauregard had risen to his feet quickly, without fuss, and was unstrapping his gun.  But Miss Belcher was quicker.  A couple of muskets lay on the sand close beside the luncheon-cloth, and in a trice she had snatched up one of them, and held our host covered.

“You have deceived us, sir,” she said quietly.

Dr. Beauregard looked along the barrel and into her eyes with an admiring, half-quizzical smile.

“Good,” said he.  “Good, but unnecessary.  That the island is inhabited I supposed you to know, since Captain Branscome tells me he reported catching sight of smoke yesterday when off the western coast; but the fellows—­there are, or were, three of them, by the way—­are no friends of mine.”

“We have only your word for it,” said Miss Belcher, without lowering her musket.

“True, ma’am,” the Doctor assented, with a bow.  “I am about to give you proof.  But first of all oblige me by listening for another moment.”

He held up his hand, and while we all listened I looked around from face to face.  Captain Branscome had unslipped his gun, and stood eyeing the Doctor with a puzzled frown.  Plinny stared up at the cliffs.  She was white to the lips, but the lips were firmly set; whereas Mr. Goodfellow’s jaw hung as though loosed from its tacklings.

So we waited for twenty seconds, maybe; but no third scream came down from the heights.

“That makes one accounted for,” said Dr. Beauregard.  “I have known, first and last, eleven parties who hunted treasure on this island.  They all quarrelled.  They quarrelled, moreover, every one of them, before getting their stuff—­such as it was—­to the boats.  Now, if you will permit me to say so, your own success—­when you obtain it—­ will be a fluke and an absurd fluke.  It will stultify every rule of precaution and violate every law of chance.  I have studied this game for close upon twenty years, and reduced it almost to mathematics; and I foresee that you will play—­nay, you have already played—­ ninepins with my most certain conclusions.  But you have as gentlefolks, with all the disabilities of gentlefolks, the one thing that all these experts have fatally lacked.  You have self-command.”

“It appears to me that we need it, at any rate,” said Miss Belcher, tartly, “if we are to be favoured just now with a lecture.”