The diamond derives its name from the Greek ADAMAS, ADAMANTOS, adamant. It has been written at various times as dyamawnte, dyamamaunt, dyamant, diamant, diamownde, dyamonde, dyamount, diamonde, diamont, dimond, dymauntz, and adamant stone. It is but pure crystallized carbon, and Arnott (Physics, 1830), writes: “The diamond has nearly the greatest light-bending power of any known substances, and hence comes in part its brilliancy as a jewel.” It is remarkable also for its extreme hardness and for its variety of colours—steel, white, blue, yellow, orange, red, green, pink and black. This “prince of gems” in days of old was considered the royal stone which only a prince was privileged to wear. The highly electrical properties ascribed by the ancients to the diamond were proved in the 17th and 18th centuries by the chemists Boyle and Du Fay, and Dr. Kunz has demonstrated today that all diamonds “phosphoresce when exposed to the rays of radium, polonium, or actinum, even when glass is interposed.” In a paper read to the Royal Society, London, November 5th, 1914, the late Sir William Crooks said: “Many substances become coloured by direct exposure to radium, the colour depending on the substance. Diamond takes a full sage-green, the depth of tint depending on the time of exposure to the radium. In addition to the change of colour the diamond also becomes radio-active, continuously giving off α, β, γ rays. The acquired colour and activity withstand the action of powerful chemical agents and continue for years with apparently undiminished activity. Removing the surface by mechanical means removes both colour and radio-activity. The appearance of an auto-radiograph made by placing an active diamond crystal on a sensitive photographic plate and the visual examination of its scintillating luminosity suggest that there is a special discharge of energy from the corners and points of the crystal.” The several experiments for the production of diamonds by artificial means have since 1880 been conducted by some eminent scientists, notably Professor Marden, Professor Henri Moissan and Sir William Crooks. For many years Sir Charles Parsons has been working closely at the problem, and the main conclusions arrived at by this scholar were communicated to the Royal Society, London, in 1918. They were as follows: That graphite cannot be converted into diamond by heat and pressure alone within the limits reached in the experiments; That there is no distinct evidence that any of the chemical reactions under pressure have yielded diamond; That the only undoubted source of diamond is from iron previously heated to high temperature and then cooled. That diamond is not produced by bulk pressure as previously supposed, but by the action of gases occluded in the metal and condensed into the centre on quick cooling.