The Assayer's Manual

Lead Oxides with Earths; Salts of Lead Oxide, viz., Lead Car-
bonate (Cerussite), Lead Chromate (Crocoisite), Lead Phos-
phate (Pyromorphite), Mimetene (Lead Arsenate), and Yel-
low Lead Ore (Wulfenite); Charges

Lead Sulphate (Anglesite, Lead Fume, Dross, Sweepings, Tail-
ings, Skimmings, etc.), Lead Silicate (Slags), Alloys of Lead
Wet Assays; Assay by Gravimetric Analysis; Assays in Blei-
berg in Carinthia, and other places

Mohr's Process; Practice of various Assayers
Volumetric Processes; Colorimetric Processes

German Copper Assay; Ores with Sulphur, Antimony, or Ar-
senic; Roasting; Pyrites; Reducing and Solvent Fusion

Examples of Charges; American Charge

Refining; Lead; Refining on the Dish with Borax.

By itself without Borax and Lead (Hungarian Speiss Assay);

With Lead and Borax (Müsen Assay)

Alloys of Copper; Cornish Copper Assay

Wet Assays; Gravimetric Assay; Modified Swedish Assay

Precipitation with Iron.

Correction for Iron that may be contained in the Precipitated

Copper; Color of pure precipitated Copper.

Precipitation with Zine free from Lead and Arsenic

Determination of the Copper in the form of Cuprous Sulphide

Apparatus for Igniting in a Current of Hydrogen

Gas Generating Flask with Funnel Tube; Assay with Sulpho-

Volumetric Assays; Parkes' Assay with Potassium Cyanide

Fleitmann's Method with Ferric Chloride

Colorimetric Methods; Heine's Assay for Poor Ores and Pro-
ducts (Slags, etc.)

Jaquelin-Hubert's Method for considerable Percentages of
Copper

Principal Ores; Assays for Non-alloys

131

Fire Assays; Collecting the Silver with Lead; Scorification

Assay; The Quantity of Lead to be Used

132

The Quantity of Borax; The Number of Samples to be Taken;

Table of Charges

133

Practice in Hungary and the Lower Harz; Crucible Assay

Charges of Various Countries

137

138

Combined Lead and Silver Assay

140

Litharge; Cupellation of the Argentiferous Lead (Assaying by

the Cupel or Cupellation)

141

Wet Assays; Balling's Volumetric Assay

144

Assays of Alloys; Dry Assays; Lead Bullion; Silver Amalgam 146

Copper Poor in Silver; Cupriferous Silver or Fine Silver
(Coins, Refined Silver, etc.)

Correction Table for the Absorption by the Cupel; Determined

by the French Commission on Coinage and Medals; Results

obtained at Freiburg; Wet Assays

Volumetric Assays; Gay-Lussac's Method with Sodium Chloride;

Preparation of the Assay Solution

Calculation; Preparation of the Normal Solutions

Volhard's Assay with Sulpho-cyanide

155

. 156

Cobalt and Nickel; Mercury; Gravimetric Analysis

Hydrostatic Assay.

Gold Ores; Non-alloys.

Mechanical Assay by Washing, for Determining the Approxi-

mate Percentage of Gold in Earthy and Gravelly Minerals,

Poor in Gold; Practice in Montana and Australia; Fire or

Fusion Assays

159

160

Smelting the Gold with Lead; Scorification Assay for Ores of
every Kind; Crucible Assay; Substances with Earths and
Oxides (Gold Quartz, Slag, Gold Sweepings)

American Gold Ores; Rhine Sand; Ores, etc., with Combina-

tions of Sulphur, Antimony, or Arsenic

Pyrites Poor in Gold; Hungarian Smelting Works

Cupellation of the Auriferous Lead; When the Laminated But-

ton breaks up; When the Flattened Button does not break up

Wet Assay (Plattner's Chlorination Process)

Alloys of Gold; Alloys of Gold and Silver, with or without

Copper

Preliminary Test for Alloys free from Copper-the Color of the
Alloy-Examination on the Touchstone; Preliminary Assay
of Cupriferous Alloys by Cupellation-with Lead Alone

The Quantity of Lead required

With an addition of Lead and Silver

Coins, the Standard of which is Known; Roll Assay for Argen-

tiferous Gold; Preliminary Assay; Weighing the Assay

Sample

Charging; Cupelling; Flattening (Laminating) the Button

Boiling in Nitric Acid