Star of the South diamond, 80 Stones other than diamonds, 70, 71, 93, 95 Strain, internal, in diamonds, 104 Sulphur, refractive index of, 103 Swazis, 39 Ultra-violet lamp to show phosphorescence, 97 Underground workings, 43 United States, diamonds in, 2 Vaalite, 20 Vaal River, 8, 16 Valuators, 73 Value of diamonds per carat, 12, 69 Value of diamonds, progressive increase in, 69 Vermiculite, 20 Volatilisation of carbon, 115 Volcanic necks, 18 Volcano, mud, 24 Wages, scale of, 35 Washing and concentrating machinery, 49 Wesselton Mine, 14, 15, 23, 35 -- -- characteristics of diamonds from, 65 Willemite, 97 Wollastonite, 20 Workings, underground, 43 Yellow ground, diamantiferous, 19 Yield of diamonds, annual, 60 -- -- -- total, 35 -- falls off with depth, 68 -- per load of blue ground, 62 Zimbabwe ruins, 40 Zircon, 20, 59, 71 -- density of, 93 Zulus, 12, 39, 40 W. BRENDON AND SON, LTD., PRINTERS, PLYMOUTH FOOTNOTES: [1] _Chemical News_, Vol. I, p. 208. [2] Mr. Paterson called “limey stuff” what is now termed “blue ground.” It was also formerly called “marl stuff,” “blue stuff,” and “blue clay.” [3] The original name for the Kimberley Mine. It was also sometimes known as “Colesberg Kopje.” [4] _Diamonds and Gold in South Africa._ By T. Reunert. Johannesburg, 1893. [5] According to Gardner Williams the South African carat is equivalent to 3·174 grains. In Latimer Clark’s _Dictionary of Metric and other Useful Measures_ the diamond carat is given as equal to 3·1683 grains = 0·2053 gramme = 4 diamond grains; 1 diamond grain = 0·792 troy grain; 151·5 diamond carats = 1 ounce troy. Webster’s _International Dictionary_ gives the diamond carat as equal to 3⅕ troy grains. _The Oxford English Dictionary_ says the carat was originally 1/144 of an ounce, or 3⅓ grains, but now equal to about 3⅕ grains, though varying slightly with time and place. The _Century Dictionary_ says the diamond carat is equal to about 3⅙ troy grains, and adds that in 1877 the weight of the carat was fixed by a syndicate of London, Paris, and Amsterdam jewellers at 205 milligrammes. This would make the carat equal to 3·163 troy grains. A law has been passed in France ordaining that in the purchase or sale of diamonds and other precious stones the term “metric carat” shall be employed to designate a weight of 200 milligrammes (3·086 grains troy), and prohibiting the use of the word carat to designate any other weight. [6] Artificial tribo-luminescent sphalerite:-- Zinc carbonate 100 parts Flower of sulphur 30 ” Manganese sulphate ½ per cent. Mix with distilled water and dry at a gentle heat. Put in luted crucible and keep at a bright red heat for from two to three hours.