in gold,145,154,170Potash, commercial examination of,338Potassium,336gravimetric determination,337Potassium cyanide,22,65,160commercial assay of,167commercial, purity of,161Powdering,4,130,448,109Precipitation,30Precipitates, drying,32igniting,32,34washing,31Preliminary assays,104,147Preparation of acids,54of other reagents,59Prill,108,129,278,287Produce,8Pyrarsenate of magnesia,383Pyrites, iron in,244sulphur in,370,376Pyrophosphate of magnesia,397Quantity to be taken for an assay,11,27,127Quartation,146Quartering,2Reagents, strength of,54Red lead for dry assays,20,22,94Reducing agents,21,94effects of charcoal, &c.,94effect of mineral sulphides,95,97,98Reduction by hydrogen,280of ferric solutions,235,242,244Regulus,18Report form,12Results, calculation of,7,13,16,38,107,131,132statement of,7Rhodium,171Roasting,22,345Rolling,149Rubidium,340Ruthenium,171Sample book,9Sampling,1effect of powdering on,449errors,447gold ores,127metals,157theory of,444Scorification of silver ores,88Scorifier,23,89Selenium,379Separation, as sulphides,57basic acetate,233molybdate,395Shales, bituminous,420Silicon and silicates,405in iron,414Silica in rocks,409in slags,414Silicates, alkalies in,333,412beryllia in,320examination of,409titanium in,411Silver,87correction for cupellation loss,103detection of,87Gay-Lussac's assay,119Gay-Lussac's assay modified,123gravimetric determination of,117in bullion,113in burnt ore,116,118in copper,114,205in galena,114in lead,113in oxide of lead,113in silver precipitate,115loss in cupellation,101pure preparation of,66Volhard's assay,121volumetric methods,119,121,123Silver lead alloys, cupellation of,98sampling of,157Silver ore, crucible assay of,90metallic particles in,108scorification of,88Size of assay charges,11,27,127Slags,19Soda-lime,425Sodium,334Sodium cyanide,160Solution,29Solutions, normal,323standard,36Specific gravity,75,436Speise,19Standard,37solutions,36Standardising,37Steel, carbon in,423chromium in,310manganese in,300Stoking,25,143Strength of reagents,54Strontium,324Sulphates and sulphur,367gravimetric determination,369volumetric determination,370Sulphides, reducing action of,9,95Sulphocyanate assay for silver,121Sulphur in blende,375in burnt ore,377in chalcocite,376in coal,419in copper,207in copper pyrites,376in mispickel,376in pyrites,370,376Sulphuretted hydrogen, preparation,57Surcharge,154System in assaying,28Table, atomic weights,433comparing thermometers,435ounces to the long ton,107ounces to the short ton,132sp. g. ammonia,438sp. g. hydrochloric acid,437sp. g. minerals,86sp. g. nitric acid,436sp. g. sulphuric acid,439sp. g. water,83Tantalum,297Tartar,20,94Tellurium,379improved test for,150Thallium,219Thorium,317Tin,271See also Black tinassay for, by vanning,273copper in,204Cornish assay,276cyanide assay,278detection of,279gravimetric determination of,281iron in,250separation of,280volumetric assay for,282Tin arsenide,284Tin phosphide,284Tin slag,290an analysis of,292tin in,290Titanium,292detection of,293in black tin,272,287in rocks,411separation, &c.,294Titration,35indirect,43,72Ton, assay,13,131,long, 2240 lbs. = 32,666.6 oz.,107short, 2000 lbs = 29,166.6 oz.,132Tungsten,295Tungstic acid,295gravimetric determination,296in black tin,285in wolfram,296Uranium,312Valuation, of copper ores,181Vanadium,310Vanning,273Volhard's assay applied to arsenic,124silver assay,121Volume-corrector,53Volumetric assay,35,38Water,7,350direct determination of,351examination of,352expansion of,83solids in,354Weighing,47small gold buttons,131Weights,47Wolfram, an analysis of,296tungstic acid in,296Yttria,319Zinc,261commercial, examination of,268commercial, iron in,249commercial, lead in,214dry assay,261gasometric assay,266gravimetric determination,262in blende,266in cyanide liquors,169in silver precipitate,266separation of,262volumetric assay,263Zirconia,317