—— crucibles, 64 ——, Grinding of, 39 ——, Melting point of, 64 ——, Mild, 39, 65 —— pots, 62 ——, Properties of, 36-38, 41 —— rings, 65 ——, Selection of 38 —— stoppers, 66 —— Strong, 39, 64 ——, Tempering, 39, 61 ——, Weathering, 39, 61 Flint glass, 4 —— stones, 4 Fluorspar, 8 Foot maker, 82 Formulas, 12, 21 Frisbie’s Feeder, 47 Furnaces, 21, 41, 51, 57 Fusibility of glass, 9 Gadget, 28 Garnet, 31 Gas-fired furnaces, 47, 51, 55 Gathering, 76, 77 Glass, Afterworkings of, 86 ——, Alkalies in, 23 ——, Alumina in, 9, 11, 20 ——, Ancient, 2 ——, Annealing, 71 ——, Cane, 97 ——, Coloured, 28 —— cloth, 101 ——, Cut, 109 ——, Enamelled, 115 ——, Founding of, 69, 74 —— furnaces, 21, 41, 51, 56 ——, Gauge, 18 ——, Grinding of, 94 ——, Hardened, 95 ——, Homogeneity of, 23 —— house pots, 62 ——, Moulds for, 77 ——, Melting of, 69 ——, Plasticity of hot, 4-16 ——, Polishing of, 92-94 ——, Properties of, 15 ——, Process of making, 15, 76 ——, Sand-blasted, 114 ——, Scum on, 69 ——, Seeds in, 105 ——, Silvered, 116 —— snow, 101 ——, Stress in, 74 ——, Strengthened, 95 ——, Temperature of melting, 20 ——, Tube, 96 ——, Types of, 15, 25 ——, Wired, 95 —— wool, 101 ——, Yellow, 28 Grinding tumblers, 110 —— plate glass, 92, 94 Hardened, 18, 23 Hermansen’s Furnace, 52, 53 History, 1 Homogeneity, 23 Honey pot making, 85 Hydrofluoric acid, 19 Introduction of glassmaking in England, 2 Iridescence, 21-101 Iron in glass, 32 Italian Aventurine, 102 Laboratory glass, 25 Ladling glass, 45 Lamp glass chimneys, 16 Lead glass, 21 —— poisoning, 14 Lehr, 71 Light and glass, 33 Lime glass, 25, 26 Machines in glassmaking, 79, 111 Mechanical boy, 86 Millefiore, 100 Moulds, 85 Opalescent glass, 95-109 Opal glass, 29, 31 Optical glass, 5, 9, 33, 104 Oxidising agents, 7 Pearl ash, 6 Pearls, 31, 116 Phosphates in glass, 8 Polariscope, 74 Potash, 6 —— glass, 24 Pots, 8-13, 27-58 ——, Annealing, 66 —— cracking, 45, 69 —— clays, 37, 64 ——, Glazing, 69 ——, Making, 62 ——, Open, 21, 27, 64 ——, Plumbago, 65 ——, rings, stoppers, 63-65, 66 —— sherds, 65 ——, Setting, 67 ——, Trolley, 46 Plaining glass, 4, 51, 69 Plasticity, 11, 16 Plate glass, 26, 93 Plumbago, 65 Pressed glass, 26, 77 Pucellas, 82 Quartz glass, 19 Réaumur’s Porcelain, 17 Recipes for glass making, 25, 26 Recuperative furnaces, 52-54 Reduction in glass, 28, 31 Regenerative furnaces, 49 Rocaille flux, 25 Roman glass, 2 Ruby glass, 28, 31 Rupert drops, 18 Saltpetre, 7 Sands, 4 Sand-blast, 114 Scratching glass, 16 Screens for pot setting, 68 Seeds in glass, 4, 13, 105 Servitor, 83 Shearing glass, 81, 83 Sheet glass, 91 Siemens Furnace, 48 Siege of furnace, 43, 44 Silica, 4, 5 Silicates in glass, 24 Silvering glass, 116 Simple glasses, 24 Soda-lime glass, 21-26 Soft glass, 5