me.

Kennedy carelessly laid his coat and hat on the inside ledge of the
ground-glass window, just opposite the spot where he had placed the
little coil on the other side of the glass. I noted that the window was
simply a large pane of wire-glass set in the wall for the purpose of
admitting light in the daytime from the hall outside.

The whole thing seemed eerie to me--especially as Poissan's assistant
was a huge fellow and had an evil look such as I had seen in pictures of
the inhabitants of quarters of Paris which one does not frequent except
in the company of a safe guide. I was glad Kennedy had brought his
revolver, and rather vexed that he had not told me to do likewise.
However, I trusted that Craig knew what he was about.

We seated ourselves some distance from a table on which was a huge,
plain, oblong contrivance that reminded me of the diagram of a
parallelopiped which had caused so much trouble in my solid geometry at
college.

"That's the electric furnace, sir," said Craig to me with an assumed
deference, becoming a college professor explaining things to the son
of a great financier. "You see the electrodes at either end? When the
current is turned on and led through them into the furnace you can get
the most amazing temperatures in the crucible. The most refractory of
chemical compounds can be broken up by that heat. What is the highest
temperature you have attained, Professor?"

"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