Smalt assay, 199

object of, 200, 201

Smaltine, 198

Smithsonite, 202

Soapstone crucibles, 67

Société genevoise, furnace of, 54
Sodium-ammonium-hydrogen phos-
phate. 79

carbonate, 80

chloride, 82

for silver assay, 151

sulphide, assay of zinc ores with,
207-212

in zinc assay, 210

ores, 256

process for determining small quan-
tities of, in iron ores and manu-
factured iron, at Creuzot, 260
volumetric assays of, 260-262
wet assays of, 259–262
Sulphuretted copper ores, 100

volumetric assay of nickel ore Sulphuric acid, accuracy of assay of

with, 197

decinormal, 45

normal, 45

verification of, 45

Solvent agents, 79, 80

Spain, charge of silver, crucible assay,
139

Spatula, 31, 34, 35

Spirit lamp, 42, 43

Stephanite, 131

Stibnite, 232

Stohmann's siphon pipette, 46

lead with, 94, 95

assay of lead with, 94, 95

Sulphurized bismuth ores, 225, 226
substances, 86

Sulphurizing agents, 81

Swansea, assay of copper slag at, 130
Swedish assay for copper, 110

modified, 110

Sweepings, gold and silver, crucible as-
say of, 139, 140

goldsmiths' samples of, 22

Sylvanite, 159

Tabular synopses, 275-277

Tamm's process for bismuth ores, 226
for preparing manganese car-
bide, 246

Tarnowitz, treatment of lead matt in, 89
Tellurium, white, 159

Storer's process of assay of lead by Tetrahedrite, 100, 224

Sublimation, 38

and distillation, furnaces for, 61, 62
Substances in a state of fusion, sam-

pling, 22

in fragments, sampling, 19, 20

Sulphide of iron, 132

of zinc, 132

Sulphides, metallic, treatment of, 261,
262

Sulphocyanide, assay of copper with,

122-124

of silver with, 156-158

for nickel assay, 196

Sulphur, 81, 256-262
assays by distillation, 257

for the determination of the
quantity of, in a substance,
258-262

dry assay (raw matt assay) of,

258

earths, 256

assays of, 257
gold with, 162-164

Tin-

losses of, by German and Cornish
methods, 215

ore containing earthy admixtures,
treatment of, 217
foreign metallic sulphides,
arsenides, and antimo-
nides, treatment of, 217
slags, treatment of, 218, 219
ores, 214

oxide combined with silicate, treat-

ment of, 218, 219

reducing, 215

slagging off of, 217, 218

Saxon assay of, 215

volumetric assays of, 222

wet assays of, 221-224

Wagner, on the decomposition of ores
with bromine, 165

with copper gives refractory oxides Wales, treatment of lead matt in, 89
and slags, 104

Tinstone, 214

and metals in combination with,
specific gravities of, 217
determination of, by washing, 214,

215

Washing samples, 28, 29
Water in various fuels, 263
Water-baths for drying samples, 26
Weighing and measuring samples, 29-

31

a pulverulent sample, 30
the button, 31

Weights and balances, 70, 71
Weil's volumetric assay of copper, 124
Welch's furnace, 60

digesting, in aqua regia, 221
Titrating, burettes for, 47, 48
Tookey, use of platinum tube by, 173
Tools and implements, 72-75
Touchstone, examination of alloy in, Welter's law, 266

167

Wet assays, 110

of copper, 110-130

of gold, 165

of lead. 98-100

of platiniferous ores, 180

of silver, 144, 145

reagents for, 83

method, 17

operation by, 38-49

White flux, 77

tellurium, 159

Wiessnegg's gas furnace, 60

Willemite, 202

Wind furnaces for free burning coal, 58
for illuminating gas, 58

or draught furnaces, 55-60

Woody fibre, composition of, 262
Working assays, Lower Harz, 279-282
Woulff bottle, 237

Wrought-iron vessels, 67
Wulfenite, 96

Yellow lead ore, 96

orpiment, 238

Zinc, 202-213

and iron in lead, 87

assay, indicators for final reaction,

209

quantity of hydrated ferric

oxide in, 210