CHAPTER III.

_The Assay of Silver Ores._ Silver and Mercury 15 Assaying of Silver Ores 16 Crucible Assay 16 Fluxes for Crucible Assay 16 Assay of Genuine Silver Ores 16 Carbonate of Soda 16 Dimensions of Crucible 16 Litharge 17 Preparation and Charge for Assay 17 Treatment in the Furnace 18 Casting-mould 18 Scorification Process 18 Fusing Cup or Scorifier 19 Special Form of Scorifier 19 Scorification Assay the Reverse of Crucible Assay 19 Charge for Scorification Assay 20 Advantages of the Process 20 Anthracite and its Object 21 Separation of the Silver from the Slag 21 Borax, use of, in Assaying 22 Continental Method of Assaying 22 Flux and Charge for Crucible 23 Details of the Process 23, 24 Skittle-pot 25 Cupellation 26 Cupel, its Mode of Manufacture 26 Cupel-mould 27 Assayer's Muffle 28 Cupel-tongs 28 Brightening 29 Sprouting 29 Weighing of Silver Assay 30 Chief Alloy of Silver 30