Faience, 129 Farewell Rock, 54 Fat clays, 29 Felspar, 7, 8, 41, 74, 104, 110, 116, 141, 144, 159 Ferric and Ferrous compounds, 12, 121, see _Iron_ Fine clays, 112 Fineness, see _Texture_ Firebricks, 14, 54, 61, 116 Fireclay, 33, 35, 52, 54, 82, 104, 108, 116, 123, 156, 166 Fissile clays, 117 Flint, 110, 116 Flint clays, 117 Floods, 85, 87, 99 Flower-pot clays, 57, 110 Fluoric vapours, 75, 77, 165 Fluviatile clays, 88, 92 Fluxes, 8, 11, 38, 39, 115, 116, 131 Food-clays, 1 Formation of clays, 48, 70 Formula of clay, 156 Free alumina, 80, 154 Free silica, 7, 80, 154, 161 Frost, 43, 86 Fuller's earth, 59, 133 Fulling cloth, 1, 133 Fusibility, 32, 58, 113, 116 Fusible clays, 116 Fusing point, 32 Fusion, 47, 113, 120, 132, 155 Ganister, 52, 54, 118 Gault, 61, 132 Geological classification, 163 Geological nature of clay, 4, 50 Glacial clays, 65, 100, 162 Glaciers, 85, 89, 100 Glass, 116 Glassy structure, 47 Glazed bricks, 119 Glazed pottery, 129 Glazed terra-cotta, 56, 129 Grades of fireclay, 120 Gravel, 7, 62, 65, 89, 100, 101, 102, 138, 144 Green colour, 14 Greensand, 133 Grinding, 80, 121 Grit, 112, see also _Millstone Grit_ Grog, 28, 31, 41, 119, 121 Growan, 78 Gypsum, 10, 12, 62 Halloysite, 118, 158 Hardness, 45 Heat, effects of, 28, 37, 39, 45, 80, 122, 146, 153, 154, 158, 159 Hydrargillite, 80 Hydro-alumino-silicates, 6 Hydrocarbons in clay, 15 Hydrolysis, 78, 97 Hygroscopic clays, 153 Hypogenic clays, 165 Ice-action, 85, 100 Ideal clay, 146 Impermeability, 40, 113 Impervious articles, 113, 155 Impurities in clays, 7, 49, 82, 102, 104, 109, 121, 126, 142, 143, 155, 162, 163 Ions, 43 Indurated clays, 18 Infusibility, 106, 119, see _Refractoriness_ Iron compounds, 7, 10, 12, 13, 20, 62, 112, 119, 121, 128, 133, 141, 145, 164 Ironstone, 62 Irregularity in shape, 131 Jurassic clays and shales, 57, 124 Kao-ling, 148 Kaolinite, 19, 80, 105, 107, 146, 149, 158 Kaolinization, 76, 77, 79 Kaolins, 9, 21, 49, 64, 71, 73, 76, 79, 82, 84, 104, 116, 141, 146, 147, 148, 165 Keele series, 55 Kellaways clay, 59, 61 Keuper marls, 57 Kiln shrinkage, 30 Kimeridge clays, 59 Knotts, 124 Lacustrine clays, 90, 91 Lake-deposited clays, 85, 88, 91 Lakes, 85, 88 Laminated clays, 53, 117, 122 Laterite, 80, 149 Lateritic action, 80, 165 Lateritic clays, 82 Lean clays, 29 Liassic clays and shales, 57, 125, 132 Lime, 7, 10, 102, 159 Lime compounds, 10, 11, 38, 41, 47, 113, 115, 116, 121, 127, 139, 142, 143, 145, 155, 157, 162, 164 Limestone, 10, 11, 52, 59, 61, 62, 88, 102, 117, 127, 132, 139 Lime troubles, 11 Loam, 57, 67, 88 London clay, 62, 63, 125 Ludwig's chart, 35