Mr. Latham turned upon him quickly.

“But you’ve explained all this to us fully,” he exclaimed sharply, indicating the cube and the guns.  “We could duplicate that if we liked.”

“Yes, you could, Mr. Latham,” replied Mr. Wynne slowly, “but you can’t duplicate the brain that isolated absolutely pure carbon from the charred residue of brown sugar.  That brain was Mr. Kellner’s; the secret died with him!”

Again there was a long silence, broken at last by Mr. Schultze: 

“Dat means no more diamonds can be made undil some one else can make der pure carbon, ain’d id?  Yah!  Und dat brings us down to der question, How many diamonds are made alretty?”

“The diamonds I showed you gentlemen were all that have been cut thus far,” replied Mr. Wynne.  “Less than twenty of the disks were used in making them.  There are now some five hundred more of these disks in existence—­roughly a billion dollars’ worth—­so you see I am prepared to hold you to my proposition that you buy one hundred million dollars’ worth of them at one-half the carat price you now pay in the open market.”

Mr. Latham passed one hand across a brow bedewed with perspiration, and stared helplessly at the German.

“The work of cutting could go on steadily here, under the direction of Mr. Czenki,” Mr. Wynne resumed after a moment.  “The secrecy of this place has not been violated for forty years.  We are now one hundred and seventy feet below ground level, in a gallery of the abandoned coal mine which gave Coaldale its name, reached underground from the cellar in the cottage.  Roofs and walls of the entire place are shored up to insure safety, and heavy felts make this chamber sound-proof, smothering even the detonation of the guns.  Mr. Czenki is the man to do the work.  Mr. Kellner, for ten years, held him to be the first expert in the world, and it would be carrying out his wishes if Mr. Czenki would agree.  If he does not I shall undertake it, and flood the market!” His voice hardened a little.  “And, gentlemen, call off your detectives.  The secret is now more yours than mine.  It destroys you if it becomes known, not me! The New York police have turned this end of the investigation over to the local police, and they are fools; all the forms have been complied with, so this place is safe.  Now call off your men!  On the day the last diamond is delivered to you, and the payment of one hundred million dollars is completed, everything here will be destroyed.  That’s all!”

“One hundred million dollars!” repeated Mr. Latham.  “Even if we accept the proposition, Schultze, how can we raise that enormous sum within a year, and preserve the secret?”

“Id ain’d a question of can, Laadham—­id’s a question of musd,” was the reply.  He thoughtfully regarded Mr. Wynne.  “Id’s only Sunday nighd, yed; we haf undil Thursday to answer, you remember.”  He turned to Mr. Latham, with a recurrence of whimsical philosophy.  “Think of id, Laadham, der alchemisds tried for dhree thousand years to make a piece of gold so big as a needle-point und didn’d; und he made diamonds so big as your fist mit a liddle cordide und some elecdricity! Mein Gott, man!  Think of id!”