“Something over three thousand degrees Centigrade,” replied Poissan, as he and his assistant busied themselves about the furnace.
We sat watching him in silence.
“Ah, gentlemen, now I am ready,” he exclaimed at length, when everything was arranged to his satisfaction. “You see, here is a lump of sugar carbon—pure amorphous carbon: Diamonds, as you know, are composed of pure carbon crystallised under enormous pressure. Now, my theory is that if we can combine an enormous pressure and an enormous heat we can make diamonds artificially. The problem of pressure is the thing, for here in the furnace we have the necessary heat. It occurred to me that when molten cast iron cools it exerts a tremendous pressure. That pressure is what I use.”
“You know, Spencer, solid iron floats on molten iron like solid water—ice—floats on liquid water,” explained Craig to me.
Poissan nodded. “I take this sugar carbon and place it in this soft iron cup. Then I screw on this cap over the cup, so. Now I place this mass of iron scraps in the crucible of the furnace and start the furnace.”
He turned a switch, and long yellowish-blue sheets of flame spurted out from the electrodes on either side. It was weird, gruesome. One could feel the heat of the tremendous electric discharge.
As I looked at the bluish-yellow flames they gradually changed to a beautiful purple, and a sickish sweet odour filled the room. The furnace roared at first, but as the vapors increased it became a better conductor of the electricity, and the roaring ceased.
In almost no time the mass of iron scraps became molten. Suddenly Poissan plunged the cast-iron cup into the seething mass. The cup floated and quickly began to melt. As it did so he waited attentively until the proper moment. Then with a deft motion he seized the whole thing with a long pair of tongs and plunged it into a vat of running water. A huge cloud of steam filled the room.
I felt a drowsy sensation stealing over me as the sickish sweet smell from the furnace increased. Gripping the chair, I roused myself and watched Poissan attentively. He was working rapidly. As the molten mass cooled and solidified he took it out of the water and laid it on an anvil.
Then his assistant began to hammer it with careful, sharp blows, chipping off the outside.
“You see, we have to get down to the core of carbon gently,” he said, as he picked up the little pieces of iron and threw them into a scrap-box. “First rather brittle cast iron, then hard iron, then iron and carbon, then some black diamonds, and in the very centre the diamonds.
“Ah! we are getting to them. Here is a small diamond. See, Mr. Spencer—gently François—we shall come to the large ones presently.”
“One moment, Professor Poissan,” interrupted Craig; “let your assistant break them out while I stand over him.”
“Impossible. You would not know when you saw them. They are just rough stones.”
“Oh, yes, I would.”
“No, stay where you are. Unless I attend to it the diamonds might be ruined.”
There was something peculiar about his insistence, but after he picked out the next diamond I was hardly prepared for Kennedy’s next remark.
“Let me see the palms of your hands.”
Poissan shot an angry glance at Kennedy, but he did not open his hands.
“I merely wish to convince you, ‘Mr. Spencer,’ ” said Kennedy to me, “that it is no sleight-of-hand trick and that the professor has not several uncut stones palmed in his hand like a prestidigitator.”
The Frenchman faced us, his face livid with rage. “You call me a prestidigitator, a fraud—you shall suffer for that! Sacrebleu! Ventre du Saint Gris! No man ever insults the honour of Poissan. François, water on the electrodes!”
The assistant dashed a few drops of water on the electrodes. The sickish odour increased tremendously. I felt myself almost going, but with an effort I again roused myself. I wondered how Craig stood the fumes, for I suffered an intense headache and nausea.
“Stop!” Craig thundered. “There’s enough cyanogen in this room already. I know your game—the water forms acetylene with the carbon, and that uniting with the nitrogen of the air under the terrific heat of the electric arc forms hydrocyanic acid. Would you poison us, too? Do you think you can put me unconscious out on the street and have a society doctor diagnose my case as pneumonia? Or do you think we shall die quietly in some hospital as a certain New York banker did last year after he had watched an alchemist make silver out of apparently nothing?”
The effect on Poissan was terrible. He advanced toward Kennedy, the veins in his face fairly standing out. Shaking his forefinger, he shouted: “You know that, do you? You are no professor, and this is no banker. You are spies, spies. You come from the friends of Morowitch, do you? You have gone too far with me.”
Kennedy said nothing, but retreated and took his coat and hat off the window ledge. The hideous penetrating light of the tongues of flame from the furnace played on the ground-glass window.
Poissan laughed a hollow laugh.
“Put down your hat and coat, Mistair Kennedy,” he hissed. “The door has been locked ever since you have been here. Those windows are barred, the telephone wire is cut, and it is three hundred feet to the street. We shall leave you here when the fumes have overcome you. François and I can stand them up to a point, and when we reach that point we are going.”
Instead of being cowed Kennedy grew bolder, though I, for my part, felt so weakened that I feared the outcome of a hand-to-hand encounter
