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 Francois—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.”