"This is the fastest cooler that's ever been made," he said. "I won't try to tell you how it works, because you probably wouldn't understand, but it's very scientific. When I throw this nugget that's forming in the crucible into it it'll be cooled off quicker than anything's ever been cooled off before. From four thousand degrees Fahrenheit down to a hundred below zero, in less than half a second! Have you any idea what that means?"
Simon realised that it was time for him to show some rudimentary intelligence.
"I know," he said slowly. "It means—"
"It means," said Mr. Fallon, taking the words out of his mouth, "that you get a pressure of thousands of millions of tons inside that nugget of molten iron; and when you break it open the diamond's inside."
He lifted the lid of his oil-can contraption, picked up the crucible with a pair of long iron tongs, and poured out a blob of luminous liquid metal the size of a small pear. There was a loud fizzing noise accompanied by a great burst of steam; and Louie replaced the lid of his cooler and looked at the Saint triumphantly through the fog.
"Now," he said, "in half a minute you'll see it with your own eyes."
The Saint opened his cigarette-case and tapped a cigarette thoughtfully on his thumbnail.
"How on earth did you hit on that?" he asked, with wide-eyed admiration.
"I used to be an assistant in a chemist's shop when I was a boy," said Louie casually. As a matter of fact, this was perfectly true, but he did not mention that his employment had terminated abruptly when the chemist discovered that his assistant had been systematically whittling down the contents of the till whenever he was left alone in the shop.
"I always liked playin' around with things and tryin' experiments, and I always believed it'd be possible to make perfectly good synthetic diamonds whatever the other experts said. And now I've proved it."