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PAINTING on glass, 104 Pair of apochromatic glasses, 208 Parison, 110 Partial dispersion, 207 Partitions in sheet tanks, 154 Path of dispersion, 207 Paving blocks, 237 Pearl-ash, 30 Phosphate, calcium, in opal, 184 Phosphoric acid, 10 Phosphorus, 184 Photographic plates, 14 Physical properties, 1, 16 and chemical composition, 6 Pipe, glass-makers', 03 Pipe-warmer, 150 Plasticity of fire-clay, 60 Plate (analysis of), 243 figured rolled, 00 glass, 120 blown, 160 grinding and polish- ing, 142 polished, 138 pouring, 138 wired, 23, 150 rolled, 00, 130 Plates, photographic, 14 Pockets, furnace, 81 Polarised light, 101 Polished plate, 120, 138 annealing kiln for, 141 bending, 147 bevelling, 148 dimensions of, 146 for mirrors, 148 opaque, 140 raw materials, 138 rolling table for, 130 silvering, 140 sorting, 146 striae in, 147 Polishing lenses, 213 lighthouse glass, 230 plate glass, 142 rubbers, 145 Pontil, 108, 110, 174, 230 Porosity test on refractories, 57 Ports, furnace, 72 in sheet tanks, 156 Pot arch, 217 arches, 63 attack by optical glass, 218 Potash, 117, 180, 242, 243 from blast furnaces, 40 carbonate of, 30 glasses, 10 nitrate of, 83 silicate of, 238 Potassium bichromate, 186 Potato, 86 Pot furnace, 73, 78, 117 charging, 80 Pot-setting for optical glass, 218 Pots, 50 burning of, 62 casting, for plate, 138 covered, 117 firing of, 217 moulding of, 60 SUBJECT INDEX 255 Pots, open and covered, 60 slip-casting of, 63 for optical glass, 217 sheet, 169 Pouring, 88, 91 plate glass, 138 Press and blow machines, 1 10 Pressed glass, 116 Presses, 126 Pressing, 96, 125 Prevention of dust, 46 Principles of annealing, 97 Prism, Nicol's, 101 Producer, gas, 67, 69 Proofs in optical glass, 221 Proof-taking, 86, 87 Properties, electrical, 25 of glass, 245 optical, 197 physical, 16 thermal, 20 Protection of eyes, 132 ladlers, 131 lenses, 211 Q. QUARTZ, 36 Quartz fibres, 235 Quartz-tridymite change, 57 IR- RADIATION, infra-red, 132 ultra-violet, 132 Radium, action of, 14 Range of optical glasses, 209 Rate of cooling, effect on colour, 180 Raw materials, 32 for optical glass, 214 polished plate, 138 rolled plate, 130 sheet, 153 grain size, 35 mixing, 79 storage of, 33 Reactions in melting, 81 Recuperative furnaces, 70 tankf urn aces (sheet), 157 Red lead, 45 Refraction, double, 213 of light, 200 Refractive index, 200, 209 Refractories, 50, 246 after-shrinkage of, 57 analyses of typical, 56 attack on, 51 fluxes in, 56 " melting-point " of, 52 porosity test, 57 spalling of, 57 tests of, 54 Refractoriness and composition, 55 . under load, 54 Regenerative furnace, 70 tank furnaces (sheet), 156 Relative partial dispersion, 207 Respirators for lead-mixing, 46 Residual spectrum, 208 Reversing valves, 71 Rings, 106 Rods, glass, 234 Rolled plate, 90, 129, 130 (analysis), 243 annealing, 134 cutting, 135 figured, 130, 137 furnaces, 77 sorting, 135 Rolling, 90 table, 133 for polished plate, 139 Rouge for polishing plate glass, 145 Ruby, copper, 181, 192 flashed, 181 gold, 182 Rubies, 235 Rupert's drops, 237 S. SAFE rate of cooling, determina- tion of, 103 St. Loupe fire-clay, 56 Salt-cake, 33, 38, 84 " setting " of, 39 Saltpetre, 40 Sampling, 86 Sand, 34 Belgian, 36 Fontainebleau, 35 for grinding plate, 144 origin of, 34 HI SUBJECT INDEX Sands, British, 35 SamiHoi, Screen, cold air, 132 Screens, chain, 131 Seed in sheet, 166 Bone MMS, •"'* SefeotJTe AMorption of light, 178 Selenium, 47, 180 colouring effect of, 185 Setting of salt-cake, 39 pots for optical glass, 218 Shears, 119 Sheet, 152 advantages of, 152 (analysis), 243 annealing, 165 blisters in, 161, 167 blowing, 159 colour of, 167 cylinders, cracking off, 163 splitting, 164 defects in, 166 drawing cylinders, 171 flat, 172 flattening, 165 flow-devices, 173 fluted, 170 Fourcault's system, 172 Frinck system, 171 made in pots, 169 mechanical production of, 171 muffled, 170 opening cylinders, 163 raw materials for, 153 seed in, 166 sizes of cylinders, 169 sorting, 166 stones in, 166 string in, 167 tank furnaces for, 153, 154, 155 white deposit on, 166 Siege, 215 Silica-alumina diagram, 55 Silica, 242, 243 brick, 51, 56, 57, 65 bubbles in vitreous, 233 fibres, 235 glass, 4 optical use of, 233 sources of, 34 thermal endurance of, 231 expansion of, 22 Silica, transparence to ultra-violet light, 233 vitreous, 231 Silica-ware, action of bases on, 232 cost of, 232 Silicate of potash, 238 soda, 238 Silicon, 183 Silicon-carbide, 71 Sillimanite, 55 Silvering, 149 Silver, colouring effect of, 191 Size of telescope objectives, 227 polished plate, 146 Skimming, 87 optical glass, 221 'Skulls in ladling, 89 Slaked lime, 41, 42 Slip- casting, pots, 63 Society, Ceramic, 246 Faraday, 246 Optical, 245 of Glass Technology, 244, 246 Soda, 242, 243 ash, 37 in sheet, 169 carbonate of, 37 nitrate of, 83 silicate of, 238 sulphate of, 38 sulphite, 84 Sodium sulphides, 183 Soft crown, 202, 204 Solidification, 2 Solution of clay by glass, 59 Sorting polished plate, 146 rolled plate, 135 sheet, 166 Sources of alkali, 37 potash, 40 Spalling of refractories, 57 Spectacle lenses, 30 Spectrum lines, 201 residual, 208 Splitting cylinders (sheet), .164 " Squatting " of fire-clay, 53 Stability, chemical, 211 Stained glass, 194 Steam, blowing by, 114 use of, in blowing, 95 Stirring, mechanical, 223 optical glass, 222 SUBJECT INDEX 257 Stones in rolled plate, 135 . sheet, 166. sulphate, 85 Storage of raw materials, 33 Stourbridge fire-clay, 56 Strained glass, 102 Strain, internal, 213 Strength, 16 crushing, 17 tensile, 17 Stress, internal, 97 Stresses, temporary, 103 Striae, 198, 218 in coloured glass, 195 in polished plate, 147 testing for, 199 String in sheet, 167 Strontium, 182 Structure, amorphous, 1 Suction devices, 92, 111 Sulphate in glass, 84 of barium, 43 lime, 43 soda, 38 stones, 85 Sulphide of antimony, colouring effect of, 184 cadmium, colouring effect of, 182 Sulphides of sodium, 183 Sulphite of soda, 84 Sulphur, 185 compounds in glass, 38 Sulphuric anhydride, 242, 243 Surfaces, chemical behaviour of, 7 T. TABLE, rolling, 132 Table of optical glasses, 202, 203, 204, 205 Table-ware, 7 "Tables," crown, 174 Tank-blocks, 58 Tank furnace, 52, 74 filling, 80 furnaces for bottles, 106 aheet, 153, 154, 155 economy of, 78 Tanks, day, 77, 117 melting process in, 86 Technology, Society of Glass, 244, 246 Telescope crown, 208 Telescope, flint, 208 objectives, limit to size of, 227 Telescopes, optical glass for large, 227 Temperature, annealing, 101 of distortion, 101 Temperatures in melting, 52 limiting, 4 Tempered glass, 237 Tempering glass, 18 Temporary stresses, 103 Tensile strength, 17 Tensions due to cooling, 98 Test for striae, 199 Tests, autoclave, 13 of durability, 1 1 laboratory glassware, 12 refractories, 54 Thallium, 180, 184 Thermal conductivity, 25 endurance, 9, 20 of silica, 231 properties, 20 Thermometer, 24 glass, 6, 242 Thermometers, zero changes in, 24 Thick glass, colour of, 177 Thread, glass, 234 Tin, colouring effect of, 183 in ruby, 184 on pressed glass, 126 Tongs, glass-makers', 109 Trade names (optical glass), 206 Transactions of the Faraday Society, 246 Translucence, 28 Transparency, 1, 27, 199 Triplets, apochoromatic, 208 Tube, combustion, 231 Tubes, devitrification in, 230 duplex, 22 hard glass, 231 Tubing, 18 combustion, 6 glass, 228 Tumbler, evolution of, 119 Tumblers, 118 Typical glasses, composition of, 241, 242, 243 U. ULTRA-MICROSCOPE, 179 Ultra-violet light, absorption of, 30 SUBJECT INDEX Ultra-violet light and silica, 233 microscope, 233 Uranium, r<. Inuring effect of, 187 Uranyl acetate, 187 nitrate, 187 UM« of coloured tflasa, 176 V. VANADIUM, colouring effect of, 185 in fire-clay, 185 Valves, reversing, 71 Variations in raw materials, 33 V.-ins. 198, 218 re dur, 6, 242 Verre, le, et le crystal, 245 Verrerie, la, au XXieme Si6cle, 245 Vrrrca et Kinnux, 245 Vessels, large, 113 Vitreous silica, 231 (nibbles in, 233 "j.tioal use of, 233 state, limit of, 3 Vitrification of fire-clay, 63 Volatilisation, losses by, 241 W. WALL thickness in furnaces, 76 Water, attack on glass by, 8 refractive index of, 209 Water-glass, 238 jugs, 121 Wetting off, 108 Wide-mouthed bottles, 115 Wine-glass, 120 Wired plate glass, 23, 150 Witherite, 43 Wool, glass-, 235 Working processes, 88 Y. YELLOW, carbon, 183 colour, silver, 181 Yield of optical glass, 227 Young's modulus, 18, 21 pR««g, LTD., LOSDOS ASD TOSBRIDOE. O m fl M I bi O 0> •f> 8 CO University of Toronto Library DO NOT REMOVE THE CARD FROM THIS POCKET Acme Library Card Pocket Under Pat. "Ref. Index File" Made by LIBRARY BUREAU. 