Includes recovering gold from color waste, the copperas process, the zinc process, the old iron binding wire process, the complex process, recovering gold from electro gilding waste, the zinc acid process, gold from rinsing waters and wash waters, the hydrogen sulphide process, recovering gold from dip gilding waste, recovering gold from old stripping solutions, recovering gold from photography old toning solutions, useful hints and tables, gold precipitating reagents, recovering silver from silver plating solutions, the zinc acid process, the sulphide of sodium process, reducing silver sulphide to metal, recovering silver from electro silvering rinsing waters, reducing chloride of silver to metallic silver with metallic iron, recovering silver from dip silvering solutions and their rinsing waters, recovering silver from old stripping solutions, recovering silver from nitric acid solutions, washing precipitates, recovering silver from glass mirror makers" solutions, recovering silver from photography old hypo solutions, recovering silver from sundry salts of silver, silver precipitating reagents, recovering silver from mixed solutions, recovering platinum from platinum solutions, recovering platinum from electro platinating solutions, separating platinum from gold united by soldering in a manner that both metals can always be distinguished, separating platinum from gold, separating platinum from silver in dental alloy, separating platinum from copper, separating platinum from lemel without any gold in it, separating platinum from lemel containing both gold and silver, separating platinum from gold, silver, copper, nickel, and other metals, the assaying of platinum wares, platinum precipitating reagents, recovering gold, silver, and platinum from waste liquid residues of every description by one operation, the electrolytic method and melting sedimentary residues.