THE LORE OF DIAMONDS.

Auckland Star, Issue XXXVI, 21 October 1905, Page 10

THE LORE OF DIAMONDS.

LECTTJRE BY SIR WTLLIAM l CROOKES. | During the visit of the British Asso- ( ciation to Kimberley. South Africa, Sir William Crookes delivered a lecture on I diamonds. , | After a description of the diamond I mines at Kimberley, the speaker dis- . i cussed the origin of the pipes in which . j the diamonds were found. These pipes, /he said, were caused by the action oi , I water vapourised by molten iron, hydro- ' J gen, and other gases being evolved, which I scored vents in the ground carrying the , i diamondiferous matter. Incidentally, he mentioned that the / Cuflinan diamond, weighing 3Q2s'i carats !U.37lb'(, iound in the PTemieT mine, near Pretoria, was a fragment, probably less than half, of a distorted octahedral crystal-, the other portions still await discovers by some fortunate miner.

Iv reference to the question of the artificial production of diamonds Sir "W. Crookes said he had long speculated as to the possibility of obtaining artificially such pressures and temperatures as would fulfil the conditions for liquefying carbon. In their researches on the gases from fired gunpowder and cordite, Sir Frederick Abel and Sir Andrew Noble obtained in closed, steel cylinders pressures as great as 95 tons to- the square inch, and temperatures as high as 4000 deg. C.

By the kindness of Sir Andrew Noble he was enabled to work upon some of the residues obtained in closed. vessels after explosions, and he submitted them to the same treatment that the granulated iron had gone through. Certain crystals were discovered which were declared by experts to be diamonds. Enlarging on the theory that diamonds came from the heavens in the form of meteorites, he said that in Arizona, on a broad, open plain, over an area about five miles in diameter, had been scattered one or two thousand masses of metallic iron, the fragments varying in weight from half a ton to a fraction of an ounce. There was little donbt these masses formed, .part of. *

I meteoric shower, although no record ex- J \ isted as to When tho fall took place. I 1 It was not uncommon for a diamond ito explode soon after it reached the \ surface; some had been known to hurst ' j ifi the: pockets of the 1 miners or when held in the warm hand, and the loss i , I was the greater because large stones i were more liable to explode or fly in pieces than small ones. By way of safe- ' I guard against explosion, some dealers f embedded large diamonds in raw potato \to ensure safe transit to England. j The diamond became radioactive after I prolonged contact with radium, and was I extremely transparent to the Rontgen ' i rays, whereas highly refracting glass, used in imitation diamonds, was almost perfectly opaque, to the rays. Sir William Crookes' lecture was repeated. The lectnre cost approximately ■\ £600, including the experiments, one of ■ which was the resolving of a diamond '■ into graphite.