href="@public@vhost@g@gutenberg@html@files@47816@[email protected]#Page_11" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">11

Spain 11 America 11 Native Silver 11 European Supplies of Silver 12 American Supply of Silver 12 The Richest Mine 12 State of the Jewellery Trade 12 Yield of Silver 13 Foreign Silver Currency 13 Chief Sources of British Silver 13 State in which it is found 14

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

CHAPTER IV.

The Cupellation of Silver Ores.

Test-ring	31
Preparation of Bone-ash	32
Defects in Bone-ash Cupel	33
Currents of Air to the Furnace	33
Withdrawal of the Silver from the Cupel	34
Removal of the Litharge, Manner of	35
Quantity of Alloy per Cupel	35
Purity of Silver after Cupellation	37
Ancient Method of Assaying	37
Dr. Lamborn on Assaying	38
Scriptural Testimony	37, 38
English System of Assay	39

CHAPTER V.

The Alloys of Silver.

Silversmith’s Alloys	40
Filigree Work	40
Alloy	41
Amalgam	41
Metals employed in the Industrial Arts	41
Metals, their various Characteristics	41
Principal Alloys of Silver	42
Copper	42
Characteristics of Copper	43
Protoxide of Copper	44
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