Dr. Schermerhorn broke in:  “Ach, it iss that I haf perfected.  Pardon me, my boy, it iss the first I haf worked from you apart.  It iss for a surprise.  I haf made in small quantities the missing ingredient.  It will form a perfect interruption to the current.  Now we go——­”

“Do you mean to say,” almost shouted Darrow, “that you have succeeded in freeing it in the metal?”

“Yes,” replied the doctor simply.

I could hear a chair overturned.

“Why, with that you can——­”

“I can do everything,” broke in the doctor.  “The possibilities are enormous.”

“And you can really produce it in quantity?”

“I think so; it iss for us to discover.”

A pause ensued.

“Why!” came the voice of Percy Darrow, awestricken.  “With fifty centigrammes only you could—­you could transmute any substance—­why, you could make anything you pleased almost!  You could make enough diamonds to fill that chest!  It is the philosopher’s stone!”

“Diamonds—­yes—­it is possible,” interrupted the doctor impatiently, “if it was worth while.  But you should see the real importance——­”

The ship careened to a chance swell; a door slammed; the voices were cut off.  I looked up.  The Nigger’s head was thrust forward fairly into the glow from the companionway.  The mask of his sullenness had fallen.  His eyes fairly rolled in excitement, his thick lips were drawn back to expose his teeth, his powerful figure was gathered with the tensity of a bow.  When the door slammed, he turned silently to glide away.  At that instant the watch was changed, and in a moment I found myself in my bunk.

Ten seconds later the Nigger, detained by Captain Selover for some trifling duty, burst into the forecastle.  He was possessed by the wildest excitement.  This in itself was enough to gain the attention of the men, but his first words were startling.

“I found de treasure!” he almost shouted.  “I know where he kept!”

They leaped at him—­Handy Solomon and Pulz—­and fairly shook out of him what he thought he knew.  He babbled in the forgotten terms of alchemy, dressing modern facts in the garments of mediaeval thought until they were scarcely to be recognised.

“And so he say dat he fine him, de Philosopher Stone, and he keep him in dat heavy box we see him carry aboard, and he don’ have to make gol’ with it—­he can make diamon’s—­diamon’s—­he say it too easy to fill dat box plum full of diamon’s.”

They gesticulated and exclaimed and breathed hard, full of the marvel of such a thought.  Then abruptly the clamour died to nothing.  I felt six eyes bent on me, six unwinking eyes moving restless in motionless figures, suspicious, deadly as cobras——­