MANUFACTURE OF DIAMONDS.

Otago Daily Times, Issue 19197, 13 June 1924, Page 10

MANUFACTURE OF DIAMONDS.

SIR CHARLES PARSONS’S EFFORTS. ABANDONMENT OF EXPERIMENTS. (From Our Own Correspondent.) LONDON, May 1. Em' over 30 years Sir Charles Parsons, famous aa the inventor of the turbine en£ine, has bet n Reeking to solve tne mastery o* the origin of the diamond, and last week lie confessed, at a meeting of the Rojal Microscopical Society, that after spending thousands of pounds in his searcli for a solution, he had been forced to the conclusion that Ihe manufacture of artificial diamonds was impossible. . In the last 50 years (writes the scientific correspondent of the Observer), many emii.tnt scientists have tried to make diamonds in the laboratory, and some have claimed to have sucre (fled. The late Sir M lUiam Crookes, in language anyone could understand, gave the apparently simple formula for manufacturing diamonds v hen ha said that the process consisted simply of dissolving charcoal (for a diamond is just charcoal, or graphite) in a liquid, and waiting for the dissolved substance to separate into crystals by slow evaporation. The intimate crystals would, he said, be true diamonds. Nature thus transforms carbon into diamonds by subjecting it to enormous pressii'-'' and temperature in the earth. The French chemist, Henri Moissan, subjected carbon to temperatures around 3600 deg C., and pressures exceeding 13 tons to the square inch, the carbon being enclosed in pure iron. The crucible containing the iion and carbon w;is th-*n plunged into cold water, which had the effect of solidifying the iron, which enclosed Die carbon in a giant grip. In this condition the dissolved carbon separated out as hard, transparent crystalline fragment indistinguishable from a true diamond But the largest “ diamond Moissan was able to produce was scarcely v'siblc to th? naked eye; 50 side by side could be comfortably accommodated in the space of one inch TWENTY YEARS' LABOUR. Sir William Crookes himself was convinced that Meissen's crystals were true diamonds, and later repeated the French chemist’s experiment with similar results. That was 18 years ago, but since then none of the many that have worked at the problem have succeeded in manufacturing a diamond big er ough to compete with the smallest natural diamond. Sir Charles Parsons, after 20 years’ labour, has admitted Irs failure, and ho has expressed the. opinion the* the microscopic crystals obtained by Moissan and Crookes were not diamonds, but carborundum or silicon compounds. Probably Sir Charles Parsons will now abondon his experiments. But others will continue to seek Ihe solution of one of .the m"st fascinating problems of chemical science. The quest, however, is enormously costly, and attended by serious risks of explosions that may forever end the career of some adventurous experimenter. The topaz, amethyst, ruby, emerald, and sapphire have all been made artificially, but the chemist has yet to imitate the methods by which Nature, in her laboratory beneath our feet, transforms a piece of black carbon into the most beautiful of all precious stones.