The Czarina of Russia _Frontispiece_ FACING PAGE Ancient Chinese crown with pearls. Ancient Chinese pearl rosary. Chinese priests keeping guard over the tombs of the kings, in Mukden, where the crowns are preserved 4 Grecian pearl and gold necklace 8 Front cover of Ashburnham manuscript of the Four Gospels 16 Francis I, King of France, 1494–1547. Isabelle de Valois 19 (From photographs by A. Giraudon) Maria Theresa (1717–1780), Queen of Hungary 24 Facsimile of title-page of decrees of Venetian Senate regulating the wearing of pearls 27 Lady Abinger. Mrs. Adair. Baroness de Forest. Hon. Mrs. Renard Gréville. Marchioness of Lansdowne. Lady Londonderry. Lady Wimborne 30 (From photographs, copyright by Lafayette, Ltd., London) Venezuela shell. Panama shell 36 Shells from Venezuela with attached pearls. Exterior view of same. X-ray photograph of shell, printed through exterior of shell and showing encysted pearls 39 Mexican pearl-oyster with adherent pearl. Group of encysted pearls in shell of Australian pearl-oyster. Mexican pearl-oyster with encysted fish. Group of encysted pearls (oriental). Reverse of same group, showing outline of the individual pearls 42 Cross section of an irregular pearl, magnified 80 diameters. Cross sections of pearls, magnified 30 diameters. Thin section of mother-of-pearl, magnified, showing sponge borings which traversed the pearl shell. Structure of conch pearl produced by fracturing, magnified 80 diameters 53 Pearls from common clam of eastern coast of America. Pearl “nuggets” from the Mississippi Valley. Wing pearls from the Mississippi Valley. Dog-tooth pearls from the Mississippi Valley 55 Actual sizes of pearls from ⅛ grain to 160 grains 57 Brooches made of petal, dog-tooth, and wing pearls 58 Gray pearls in the possession of an American lady and brooch from Tiffany & Co.’s exhibit, Paris Exposition, 1900 60 Shell of pearl-oyster with attached pearl 68 Pinna or wing shell. Pearl-oyster of Ceylon 72 Shell and pearls of the common conch 76 Cargo boat in pearl fishery of the Persian Gulf. Huts of mats and palm leaves, the homes of the pearl fishermen at Menamah, Bahrein Islands, Persian Gulf 87