in gold, 145, 154, 170

Potash, commercial examination of, 338

Potassium, 336
gravimetric determination, 337

Potassium cyanide, 22, 65, 160
commercial assay of, 167
commercial, purity of, 161

Powdering, 4, 130, 448, 109

Precipitation, 30

Precipitates, drying, 32
igniting, 32, 34
washing, 31

Preliminary assays, 104, 147

Preparation of acids, 54
of other reagents, 59

Prill, 108, 129, 278, 287

Produce, 8

Pyrarsenate of magnesia, 383

Pyrites, iron in, 244
sulphur in, 370, 376

Pyrophosphate of magnesia, 397


Quantity to be taken for an assay, 11, 27, 127

Quartation, 146

Quartering, 2


Reagents, strength of, 54

Red lead for dry assays, 20, 22, 94

Reducing agents, 21, 94
effects of charcoal, &c., 94
effect of mineral sulphides, 95, 97, 98

Reduction by hydrogen, 280
of ferric solutions, 235, 242, 244

Regulus, 18

Report form, 12

Results, calculation of, 7, 13, 16, 38, 107, 131, 132
statement of, 7

Rhodium, 171

Roasting, 22, 345

Rolling, 149

Rubidium, 340

Ruthenium, 171


Sample book, 9

Sampling, 1
effect of powdering on, 449
errors, 447
gold ores, 127
metals, 157
theory of, 444

Scorification of silver ores, 88

Scorifier, 23, 89

Selenium, 379

Separation, as sulphides, 57
basic acetate, 233
molybdate, 395

Shales, bituminous, 420

Silicon and silicates, 405
in iron, 414

Silica in rocks, 409
in slags, 414

Silicates, alkalies in, 333, 412
beryllia in, 320
examination of, 409
titanium in, 411

Silver, 87
correction for cupellation loss, 103
detection of, 87
Gay-Lussac's assay, 119
Gay-Lussac's assay modified, 123
gravimetric determination of, 117
in bullion, 113
in burnt ore, 116, 118
in copper, 114, 205
in galena, 114
in lead, 113
in oxide of lead, 113
in silver precipitate, 115
loss in cupellation, 101
pure preparation of, 66
Volhard's assay, 121
volumetric methods, 119, 121, 123

Silver lead alloys, cupellation of, 98
sampling of, 157

Silver ore, crucible assay of, 90
metallic particles in, 108
scorification of, 88

Size of assay charges, 11, 27, 127

Slags, 19

Soda-lime, 425

Sodium, 334

Sodium cyanide, 160

Solution, 29

Solutions, normal, 323
standard, 36

Specific gravity, 75, 436

Speise, 19

Standard, 37
solutions, 36

Standardising, 37

Steel, carbon in, 423
chromium in, 310
manganese in, 300

Stoking, 25, 143

Strength of reagents, 54

Strontium, 324

Sulphates and sulphur, 367
gravimetric determination, 369
volumetric determination, 370

Sulphides, reducing action of, 9, 95

Sulphocyanate assay for silver, 121

Sulphur in blende, 375
in burnt ore, 377
in chalcocite, 376
in coal, 419
in copper, 207
in copper pyrites, 376
in mispickel, 376
in pyrites, 370, 376

Sulphuretted hydrogen, preparation, 57

Surcharge, 154

System in assaying, 28


Table, atomic weights, 433
comparing thermometers, 435
ounces to the long ton, 107
ounces to the short ton, 132
sp. g. ammonia, 438
sp. g. hydrochloric acid, 437
sp. g. minerals, 86
sp. g. nitric acid, 436
sp. g. sulphuric acid, 439
sp. g. water, 83

Tantalum, 297

Tartar, 20, 94

Tellurium, 379
improved test for, 150

Thallium, 219

Thorium, 317

Tin, 271 See also Black tin
assay for, by vanning, 273
copper in, 204
Cornish assay, 276
cyanide assay, 278
detection of, 279
gravimetric determination of, 281
iron in, 250
separation of, 280
volumetric assay for, 282

Tin arsenide, 284

Tin phosphide, 284

Tin slag, 290
an analysis of, 292
tin in, 290

Titanium, 292
detection of, 293
in black tin, 272, 287
in rocks, 411
separation, &c., 294

Titration, 35
indirect, 43, 72

Ton, assay, 13, 131,
long, 2240 lbs. = 32,666.6 oz., 107
short, 2000 lbs = 29,166.6 oz., 132

Tungsten, 295

Tungstic acid, 295
gravimetric determination, 296
in black tin, 285
in wolfram, 296


Uranium, 312

Valuation, of copper ores, 181

Vanadium, 310

Vanning, 273

Volhard's assay applied to arsenic, 124
silver assay, 121

Volume-corrector, 53

Volumetric assay, 35, 38


Water, 7, 350
direct determination of, 351
examination of, 352
expansion of, 83
solids in, 354

Weighing, 47
small gold buttons, 131

Weights, 47

Wolfram, an analysis of, 296
tungstic acid in, 296


Yttria, 319


Zinc, 261
commercial, examination of, 268
commercial, iron in, 249
commercial, lead in, 214
dry assay, 261
gasometric assay, 266
gravimetric determination, 262
in blende, 266
in cyanide liquors, 169
in silver precipitate, 266
separation of, 262
volumetric assay, 263

Zirconia, 317