COPPER--Introductory 175 Dry assay 176 Valuation of copper ores 181 Wet methods 183 (1) Electrolytic assay 184 Volumetric methods 194 (1) Cyanide method 194 (2) Iodide method 199 (3) Colorimetric method 203 Examination of commercial copper 205 LEAD 211 Dry assay 211 Wet assay 213 (1) Gravimetric method 213 (2) Volumetric method 214 (3) Colorimetric method 218 THALLIUM 219 BISMUTH 220 Dry assay 221 Wet method 221 (1) Gravimetric determination 222 (2) Colorimetric assay 223 ANTIMONY 225 Dry assay 225 Wet method 227 (1) Gravimetric assay 228 (2) Volumetric method 229 CHAPTER XI. IRON, NICKEL, COBALT, ZINC, CADMIUM. IRON 231 Gravimetric determination 233 Permanganate and bichromate methods 234 Stannous chloride method 244 Colorimetric determination 247 NICKEL 251 Dry assay 251 Electrolytic assay 254 Titration by cyanide 255 COBALT 259 ZINC 261 Gravimetric method 262 Volumetric method 263 Gasometric method 266 CADMIUM 269 CHAPTER XII. TIN, TUNGSTEN, TITANIUM.