Mr. E. G. Acheson, One of the Pioneers in the Investigation of High Temperatures.
"I think the possibility of manufacturing genuine diamonds," he said to me, "has dazzled more than one young experimenter. My first efforts in this direction were made in 1880. It was before we had command of the tremendous electric energy now furnished by the modern dynamo, and when the highest heat attainable for practical purposes was obtained by the oxy-hydrogen flame. Even this was at the service of only a few experimenters, and certainly not at mine. My first experiments were made in what I might term the 'wet way'; that is, by the process of chemical decomposition by means of an electric current. Very interesting results were obtained, which even now give promise of value; but the diamond did not materialise.
"I did not take up the subject again until the dynamo had attained high perfection and I was able to procure currents of great power. Calling in the aid of the 6,500 degrees Fahrenheit or more of temperature produced by these electric currents, I once more set myself to the solution of the problem. I now had, however, two distinct objects in view: first, the making of a diamond; and, second, the production of a hard substance for abrasive purposes. My experiments in 1880 had resulted in producing a substance of extreme hardness, hard enough, indeed, to scratch the sapphire—the next hardest thing to the diamond—and I saw that such a material, cheaply made, would have great value.
"My first experiment in this new series was of a kind that would have been denounced as absurd by any of the old-school book-chemists, and had I had a similar training, the probability is that I should not have made such an investigation. But 'fools rush in where angels fear to tread,' and the experiment was made."
This experiment by Mr. Acheson, extremely simple in execution, was the first act in rolling the stone from the entrance to a veritable Aladdin's cave, into which a multitude of experimenters have passed in their search for nature's secrets; for, while the use of the electrical furnace in the reduction of metals—in the breaking down of nature's compounds—was not new, its use for synthetic chemistry—for the putting together, the building up, the formation of compounds—was entirely new. It has enabled the chemist not only to reproduce the compounds of nature, but to go further and produce valuable compounds that are wholly new and were heretofore unknown to man. Mr. Acheson conjectured that carbon, if made to combine with clay, would produce an extremely hard substance; and that, having been combined with the clay, if it should in the cooling separate again from the clay, it would issue out of the operation as diamond. He therefore mixed a little clay and coke dust together, placed them in a crucible, inserted the ends of two electric-light carbons into the mixture, and connected the carbons with a dynamo. The fierce heat generated at the points of the carbons fused the clay, and caused portions of the carbon to dissolve. After cooling, a careful examination was made of the mass, and a few small purple crystals were found. They sparkled with something of the brightness of diamonds, and were so hard that they scratched glass. Mr. Acheson decided at once that they could not be diamonds; but he thought they might be rubies or sapphires. A little later, though, when he had made similar crystals of a larger size, he found that they were harder than rubies, even scratching the diamond itself. He showed them to a number of expert jewellers, chemists, and geologists. They had so much the appearance of natural gems that many experts to whom they were submitted without explanation decided that they must certainly be of natural production. Even so eminent an authority as Geikie, the Scotch geologist, on being told, after he had examined them, that the crystals were manufactured in America, responded testily: "These Americans! What won't they claim next? Why, man, those crystals have been in the earth a million years."
Mr. Acheson decided at first that his crystals were a combination of carbon and aluminium, and gave them the name carborundum. He at once set to work to manufacture them in large quantities for use in making abrasive wheels, whetstones, and sandpaper, and for other purposes for which emery and corundum were formerly used. He soon found by chemical analysis, however, that carborundum was not composed of carbon and aluminium, but of carbon and silica, or sand, and that he had, in fact, created a new substance; so far as human knowledge now extends, no such combination occurs anywhere in nature. And it was made possible only by the electrical furnace, with its power of producing heat of untold intensity.
The Furnace-Room, where Carborundum is Made.