TRANSCRIBER’S NOTE Italic text is denoted by _underscores_. Footnote anchors are denoted by [number], and the footnotes have been placed at the end of the book. A subscript is denoted by _{x}, for example C_{2}. Basic fractions are displayed as ½ ⅓ ¼ etc; other fractions are shown in the form a/b, for example 1/144 or 5/12. Some minor changes to the text are noted at the end of the book. HARPER’S LIBRARY _of_ LIVING THOUGHT [Illustration: (publisher colophon)] [Illustration: DIAMONDS BY SIR WILLIAM CROOKES HARPER & BROTHERS LONDON & NEW YORK] [Illustration: THE CULLINAN DIAMOND. From a photograph by the Author. (See pages 76-79.) Frontispiece.] ·DIAMONDS· BY SIR WILLIAM CROOKES LL.D., D.Sc., F.R.S. Foreign Sec. R.S., Hon. LL.D. (Birmingham), Hon. Sc.D. (Camb. and Dubl.), Hon. D.Sc. (Oxon. and Cape of Good Hope); Past Pres. Chem. Soc., Brit. Assoc., Inst. Elect. Eng., Soc. Psych. Res.; Hon. Mem. Roy. Phil. Soc. Glasgow, Roy. Soc. N.S.W., Pharm. Soc., Chem. Metall. and Mining Soc. of South Africa, Amer. Chem. Soc., Amer. Philos. Soc., Roy. Soc. Sci. Upsala, Deutsch. Chem. Gesell. Berlin, Psychol. Soc. Paris, “Antonio Alzate” Sci. Soc. Mexico. Sci. Soc. Bucharest, Reg. Accad. Zelanti, Aci Reale; Corresp. Inst. de France (Acad. Sci.), Corresp. Mem. Bataafsch Genoots. Rotterdam, Soc. d’Encouragement pour l’Indust. Paris, For. Mem. Accad. Lincei Rome. WITH 24 ILLUSTRATIONS LONDON AND NEW YORK HARPER & BROTHERS 45 ALBEMARLE STREET, W. 1909 TO MY WIFE MY COMPANION AND FRIEND OF FIFTY-FOUR YEARS. TO HER JUDGMENT AND ADVICE I OWE MORE THAN I CAN EVER REPAY AND TO HER I DEDICATE THIS BOOK. PREFACE The following pages are based on personal observations during two visits to Kimberley, in 1896 and 1905, and on personal researches on the formation and artificial production of diamonds. In 1896 I spent nearly a month at Kimberley, when Mr. Gardner F. Williams, the General Manager of the De Beers Consolidated Mines, and the managers of neighbouring mines, did their utmost to aid in my zealous quest for reliable information. They gave me free access to all workings above and below ground, allowed me to examine at leisure their stock and to take extracts from their books. I had exceptional opportunities of studying the geology of the Diamond and of noting the strange cataclysmal facts connected with the birth, growth, and physics of the lustrous stones. In 1905 with my wife I returned to Kimberley. We were members of the British Association which held its meeting that year in South Africa. I was asked to give one of the Association lectures at Kimberley and it was natural for me to discourse “On Diamonds.” During our stay we were the guests of Mr. Gardner Williams.