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Jt Practical Manual of Miner- 
als, Mines and Mining. By 

Prof. H. S. Osborn, LL.D. Illus- 
trated by 171 Engravings. Second 
Edition. Revised and Enlarged. 
393pp., 8vo $4.50 

Underground Treasures: How 
and Where to Find Them. A 

Key for the Ready Determination of 
all the Useful Minerals within the 
United States. By James Orton, 
A. M. A new Edition, with Addi- 
tions. Illustrated. 211pp., 16mo. $1.50 

Mineralogy Simplified. By 

Henry Erni, A. M., M. D. Third 
Edition, revised, re-arranged and 
with the addition of entirely new 
matter, including Tables for the 
Determination of Minerals by Chem- 
ical and Pyrognostic Characters. By 
Amos P. Brown, E. M., Ph. D., As- 
sistant Professor in charge of the 
Department of Geology and Miner- 
alogy in the University of Pennsyl- 
vania. 350 pages. Illustrated by 96 
engravings, pocket-book form, full 
flexible morocco, gilt edges. . $2.50 






Prof. H. S. OSBORN, LL.D, 








tfO 5 

THE" 1 


' COPY B. 

Copyright by 




Printed by the 


53 and 55 North Queen Street, 

Lancaster, Pa., U. S. A. 


The gratifying success of the fifth edition of 
The Prospector's Field-Book and Guide, unmis- 
takably indicating the firm hold which it has on 
the confidence of Prospectors, has rendered necessary 
the preparation of this, the sixth edition. In doing 
this, the book has been carefully revised through- 
out, and where considered desirable, it has been 
enlarged. These revisions and amplifications add 
greatly, as it is believed, to the value and usefulness 
of the volume, and bring it fully up to date. 

The work of revision has been undertaken by the 
same competent hand that so satisfactorily edited 
the second, third, fourth and fifth editions. As 
now presented to the public, it is felt to be a com- 
plete and thoroughly reliable guide and companion 
to the intelligent and enterprising searcher after 
ores and other useful minerals, including gems and 
gem-stones ; the very best that has ever been pub- 
lished in any language. It has been provided w T ith 
a thorough Table of Contents and an Index, ren- 



dering reference to any subject in it prompt and 

In conclusion the publishers would add, that they 
confidently look for a sale of this edition, the largest 
in number that they have thus far issued, equal in 
its rapidity and extent to that of those which have 
preceded it. 

H. C. B. 

Philadelphia, Nov. 2, 1903. 


The death of Dr. Osborn, two years ago, renders 
it necessary that the Publisher should prepare the 
preface to this revised edition of The Prospector's 


The fact of a second edition of this book having 
been called for so soon after the publication of the 
large first edition, justifies the belief that it has 
supplied a public requirement. The task of revis- 
ing the work has devolved upon thoroughly com- 
petent hands ; and whilst it has been aimed, by the 
insertion of further information regarding the sub- 
jects treated in the original edition, to make it still 
more acceptable to those for whom it was prepared, 
a new chapter has also been added on Petroleum, 
Ozocerite, Asphalt and Peat, together with a Glos- 
sary of Terms used in prospecting, mining, miner- 
alogy, geology, etc. 

While the work of revision has been done with 
conscientious care, under the supervision of the 
Publisher, it can hardly be hoped that it has been 
so well done as if Dr. Osborn, with his profound 
knowledge of the subject treated, had been alive to 
direct it for himself, and in his own manner. 



Henry Stafford Osborn was born in Philadelphia, 
August 17, 1823, and died in New York City, Feb- 
ruary 2, 1894. He was graduated at the Univer- 
sity of Pennsylvania in 1841 ; went abroad in 1843 
or 1844 ; studied at Bonn, Germany, and at the 
Polytechnic Institution of London. Before the 
civil war he held the chair of Natural Science at 
Roanoke College, Va., and in 1866 accepted a pro- 
fessorship at Lafayette College, Easton, Pa. Leav- 
ing Lafayette in 1870, he became, in 1871, Professor 
in Miami University at Oxford, Ohio. In 1865 he 
received from Lafayette College the degree of LL.D. 

In 1869 he published "The Metallurgy of Iron 
and Steel ; " in 1888, " A Practical Manual of Min- 
erals, Mines and Mining ;" in 1892, the first edition 
of The Prospector's Field-Book and Guide, the 
success of all of which books has been pronounced. 

Personally, Dr. Osborn was charming, full of in- 
formation on a wide range of subjects, which he 
had studied thoroughly ; enthusiastic, amiable and 
just ; and the relations of his publisher with him 
during a quarter of a century, will ever be among 
the brightest and best recollections of that pub- 
lisher's long career in business. 

Philadelphia, January 15, 1896. 


In the following pages we have attempted to 
present such a view of the whole subject of pro- 
specting for the useful minerals that any liberally 
educated reader may fully comprehend our mean- 
ing. We have therefore explained special terms 
where we have thought it convenient to use them, 
and where the technically educated student would 
not need an explanation. 

It must be understood that the subjects of chem- 
istry, mineralogy, and metallurgy are introduced 
only for their practical bearing upon the ores in 
hand, or those sought for, and not for theory, or the 
philosophy of the operation, much as such theory 
or philosophy would please and instruct. The 
prospector must, therefore, refer to larger works if 
he desire to be instructed in the principles govern- 
ing the sciences, the teachings of which we have 
frequently made use of. 

We would suggest to any one intending to use 
this volume for practical work, to become ac- 
quainted with the whole book before attempting to 
use any special part alone. The object and con- 
struction have made it necessary to treat some 



special topics without repeating principles and 
methods already given in some part of the work, 
but which bear some relation to the topic under 
immediate consideration. 

The Table of Contents and Index have both been 
carefully prepared, and being very fall, will make 
reference to any subject in the volume easy and 

Oxford, Ohio, Jan. 5, 1892. 





Disappointment and loss caused by lack of knowledge by pros- 
pectors 1 

Technical mineralogy, the first study of the prospector; Defini- 
tion of a mineral; Definition of rocks; Principal constituents 

of rocks 2 

Quartz and its varieties; Feldspar 3 

Most important kinds of feldspar 4 

Micas; Most important species of mica 5 

Amphibole, often called hornblende 7 

Pyroxene, including augite 9 

Chlorite 10 

Talc; Serpentine; Elementary composition of minerals . ■ . 11 
Calculation of the amounts of the elements going to make up 
any given mass; Definition of acids, bases and salts; Ex- 
amples of minerals which are salts 12 

Examples of silicates; Colors of minerals 13 

Effect of the intermixture of coloring matter 14 

Polychroism; Phosphorescence ... 15 

Colors and forms under which native metals may appear . . 16 

Cleavage; Fracture; Streak . . 17 

Hardness; Scale of hardness 18 

Manner of trying the hardness of a mineral; What may be 
learned from the test of hardness; Flexibility and elasticity; 

Smell ... 19 

Taste; Malleability; Ductility 20 

Lustre; Definition of the various kinds of lustre 21 

Specific gravity; Definition of the specific gravity of a mineral; 

Weight and form of minerals 22; 




Importance of a knowledge of the characteristics of the rock 
associated with minerals; Desirability of a general knowledge 
of the manner in which the geologic rocks are laid down 23 

Signs by which the name of the sedimentary rock may be 
determined; Horizons of the rocks 24 

Movements of the earth's crust illustrated by a section showing 
contorted strata due to lateral pressure; Practical geology; 
Horizons sterile in ores ... 25 

Horizons in the United States which abound in the useful 
metals; Classification of rocks; Definition of rocks .... 26 

General sameness in the geological horizons throughout the 
world; Table showing the relations of certain rocks one to 
another; Igneous rocks 27 

Metamorphic rock 28 

The aqueous rocks; Sandstone, illustrated and described; Shale, 
illustrated and described; Granite 29 

Varieties of granite 30 

Granite with black mica and feldspar crystals, with quartz as 
chief base, illustrated and described; First indications of a 
deposit possessing economic value; Where metalliferous de- 
posits should be looked for 31 

Mode of occurrence of the valuable minerals and metal-bearing 
deposits of the earth; Lodes 32 

Cross section of a formation or horse 33 

Transverse section of solid quartz lode with casing; Beds and 
layers ... 34 

Irregular deposits; Surface deposits 35 

Selection of a spot for starting actual prospecting operations; 
Most likely localities of auriferous lodes; Source of gold in 
the right-hand branch of a forked river . . 36 

The right-hand theory fully established by practical experience; 
Spots upon which the sun shines before noon richest in metal; 
Explanation of this theory; The color of the rocks as a guide 
to the prospector 37 

Necessity of paying attention to the wash of rivers and creeks . 38 

Pilot stones; Placers and placer gold £9 

Character of placer diggings; Forms of alluvial deposits, illus- 
trated and described 40 

Estimating the value of alluvial claims 41 



Indicative plants; Vegetation indicative of lead and iron - . 42 

Vegetation indicative of limestone, phosphate, silver, and zinc; 
Hints in looking for deposits where superficial deposits are 
known to occur . . 43 

Mode of occurrence of gold in Australia and California; Mode 
of occurrence of other minerals; Points to be observed in ex- 
amining a lode 44 

Table showing the association of ore in metalliferous veins . . 45 



On what chemical tests for minerals depend; Illustrations of the 

character of changes brought about by chemical tests • 46 

Requirements for blow-pipe practice; Manner of preparing dry 

carbonate of soda 47 

Borax and other supplies; Mode of using the blow-pipe ... 48 
Practice with the blow-pipe by blowing upon a piece of charcoal; 
Colors of a candle flame ; Oxidizing and reducing flames 

illustrated and described 49 

Roasting; Illustration and practice in showing the characteristic 
power of the oxidizing and reducing flames; Mode of making 

a platinum wire loop, illustrated 51 

How to make a blow-pipe ... 52 

Principal means of chemically testing minerals before the blow- 
pipe; Blow-pipe experiments; Recognition of the presence of 

metals by the color imparted to fused borax 53 

Table of color indications 54 

Mode of testing with carbonate of soda on charcoal 55 

Observations and inferences from the above test 56 

Test for sulphur and arsenic and other substances ; Tests in 
glass tubes 57 



The composition of minerals indicated by their forms ; Classes 

or systems of crystalline forms; Isometric system 59 

The cube, illustrated and described; Variations of the cube . . 60 
The octahedron and dodecahedron, illustrated and described; 
Tetragonal system 61 


..... -x- . PAGE 

The prism, illustrated and described; The zircon, illustrated and 

described; Hexagonal system r . . 62 

Forms of the hexagonal system, illustrated and described ... 63 

Orthorhombic system .... 64 

Monoclinic system; Triclinic or thrice inclined system; Illustra- 
tions of the different systems of crystallization 65 

Distinction between the turquois, lazulite and lapis lazuli ... 66 

The topaz and its crystallization 67 

Meteoric iron ; Ruby and sapphire 68 

Serious mistake of a Paris firm of jewelers; Localities of gems . 69 



To measure heights which are inaccessible 70 

To measure areas, illustrated by examples 72 

To measure an inaccessible line, illustrated 75 

The prism compass and its use 77 



Wet Method; Preliminary examination; Detection of sulphur, 
arsenic and selenium ; Determination of native gold or silver. 79 

Indication of copper; Detection of antimony and tin; Determi- 
nation of manganese, alumina, magnesia, lime, zinc, cobalt 
and nickel 80 

Determination of uranium, titanium and mercury; Detection of 
carbonates; Examination of sandstone 81 

Qualitative analysis of ores; Directions for the wet method of 
analysis . . . . 82 

Indications of silver, lead or mercury in the assay 84 

Apparatus for making hydrogen sulphide, described and illus- 
trated; Manner of cutting off the bottom of a bottle .... 85 

The filtrate; What the precipitate may contain 87 

Treatment of the precipitate; Precipitation of chromium oxide; 
Blow-pipe test for chromium; Precipitation of alumina; Defi- 
nition of an excess 88 

Precipitation of manganese, cobalt and nickel 90 

^Establishment of the presence of mercury oxide and lead sul- 
phate 91 



Indications of bismuth and cadmium, and of copper, sulphur 

and gold 92 

Detection of platinum and arsenic; Indication of antimony and 

tin 93 

Dry assay of ores; Crucibles; Scorifiers; The cupel; The muffle; 

An assay furnace, illustrated and described 94 

Brasquing; Portable assay furnace for field testing 95 

Scales, weighing, etc . 96 

Pulverization 97 

Testing gold and silver ores; Cupellation 98 

Flax for melting the ore in a crucible 99 

Process of assaying gold quartz 100 

Testing of lead ore, galena; Testing of copper, tin, mercury 

and antimony ores 101 

Directions for making an excellent fire lute 102 

Special Mineralogy, 
Importance of studying minerals from actual specimens ; Dis- 
tribution of gold . 103 

Occurrence of gold in sea water; Chief sources of the supply of 
gold ; Principal mode of occurrence of gold ; Composition of 

native gold 104 

Mexican rhodium gold ; Gold amalgam ; Black gold; Bismuth 
gold ; To detect a content of native gold in pyrites ; Crystal- 
lization of gold ; Gold crystals, illustrated ; Large lump of 
gold found at Forest Creek, Victoria, Australia, illustrated . 105 
Physical properties of gold; Variations in the color of gold . . 106 
Action of gold under the blow-pipe and towards acids .... 107 

The bat ea, described and illustrated; Panning out 108 

The cradle or rocker, described and illustrated Ill 

The long torn, described and illustrated 112 

Sluices and their construction 114 

Hydraulic mining, described and illustrated . ... 115 

Burning and drifting in the Forty-Mile District, Alaska . . . 118 

Lode prospecting ... 119 

Directions for making an amalgamating assay 120 



Construction of a retort » 121 

Calculating the amount of gold per ton an ordinary battery 

might expect to save; Darton's gold test 122 

Variation of the above test; Other forms and conditions of gold. 123 

Placer gold; Gold amalgam 124 

Geology of gold; Occurrence of gold in quartz; Original posi- 
tion of gold ... . . 125 

Gold in granitic regions, illustrated by section showing the two 
conditions under which gold is usually found in rock and 

drift 126 

Significance of an ironstone ''blow-out;" Peculiar and seem- 
ingly irregular deposits of gold . . . 127 

Origin of metamorphic rocks; Igneous rocks and their compo- 
sition; Composition of metamorphic granite . . . . 129 
Where the most paying gold is found; Gold in combination . . 130 
To separate gold in metallic sulphides, for instance, iron pyrites; 

Mode of making fuming nitric acid 131 

Another method of detecting and separating the gold .... 133 

What constitutes profitable gold mining ... 134 

Method of separating gold which gives very accurate results . 135 
Description of the Yukon gold district, Alaska; Dissemination 
of gold in Alaska; Where the profitable deposits have been 

found 136 

Derivation of the gold of the Yukon district 137 

Extent of the gold-bearing rocks 138 

Rule for ascertaining the amount of gold in a lump of aurifer- 
ous quartz 139 



Tellurium minerals; Tellurium; Nagyagite, foliated or black 

tellurium 141 

Hessite; Petzite; Sylvanite or graphic tellurium 142 

Value of tellurides; Platinum, its occurrence and properties; 

Platinum in California and Oregon . . 143 

Chief source of supply of platinum; Consumption of platinum 

in the United States 144 

Sperrylite and its occurrence; How to distinguish platinum; 

Chemical test for platinum > 145 



Separation of platinum from gold and other metals ; Prepara- 
tion of stannous chloride 146 

Iridium; Osmium; Palladium; Silver, its occurrence and prop- 
erties ; Mispickel ; How to distinguish native silver before 

the blow-pipe 147 

Chemical test for silver 148 

Derivation of most of the silver of commerce ; Other forms in 

which silver is found; Silver glance or argentite 149 

Ceragyrite or horn silver .... . . 150 

Stephanite or brittle silver ore ; Red silver ore or ruby silver ; 

Pyrargyrite 151 

Bromic silver or bromyrite ; Valuing silver ores ; Geology of 
silver ores, illustrated by sections across the Comstock Lode 
and surrounding strata, east and west, and north and south, 

and showing the mines and the surface 152 

Non-metallic substances of the Comstock Lode 153 

Extent and value of the Comstock Lode 155 

Occurrence of silver at the Eureka Mines, Nevada; Peculiarity 

of the limestone overlying the Eureka Mines 157 

Geology of the Ruby Hill Mines ; The Emma Mine ; General 
geologic conditions in which silver ores are found 158 



Copper, its occurrence and properties ; Manner of testing min- 
erals containing copper 160 

Natural combinations of copper; Cuprite, red copper ore or red 
copper 161 

Chalcocite, copper glance or vitreous copper; Tetrahedrite or 
gray copper ore 162 

Chalcopyrite or copper pyrites 163 

Peacock ore ; Chrysocolla or silicate of copper ; Black oxide of 
copper 164 

Malachite or green carbonate of copper ; Azurite or blue car- 
bonate of copper; Variegated copper pyrites 165 

Ores which furnish the bulk of the world's consumption of cop- 
per ; Geology of copper, illustrated by section of the copper 
bed at the Dolly Hide Mine, section of strata in Lake Supe- 
rior copper region, and section of the Eagle Vein, Lake 
Superior 166 



Facts to be remembered to become ready in the detection of 
copper; Kocks with which copper is associated 1G8 

Examination of specimens for copper ; Examination of the 
region in which copper is supposed to occur . .... 169 

To obtain the per cent, of copper in an ore 170 

Precautions to be observed in the assay of copper 171 



Lead, its occurrence and properties ; Galena ; Test for silver in 

galena 174 

Order of strata in the lead district of Wisconsin, Illinois and 
Iowa ; Geology and form of lodes of the galena ores illus- 
trated by lead lode in micaceous slate in mine near Middle- 
town, Conn 175 

Carbonate of lead or cerussite, illustrated by section of strata in 

California Gulch, Colorado . • 176 

Sulphate of lead or anglesite ; Phosphate of lead or pyromor- 

phite; Chromate of lead or crocoite 177 

Lead ochre or massicot ; Lead-antimony ores ; Jamesonite ; 
Zinkenite ; The geology of lead illustrated by a section of 

galena limestone 178 

Circulation of water in lead veins 179 

Deposit of lead in a fissure of the limestone; Chief sources of 

lead in the United States 180 

Tin; Assay of tin ore 181 

Cassiterite or tin stone; Wood tin; Toad's eye tin; Stream tin. 182 

Discovery of tin in Banca and Belliton .... 183 

Tin pyrites (sulphide of tin); Occurrence of cassiterite in the 

United States 184 

Cassiterite as a type of a strongly marked class of deposits . . 185 

Minerals most commonly associated with tin . 186 

Wolframite, its properties and uses 187 



Zinc; Chief ores of zinc; Smithsonite or zinc carbonate; Cala- 
mine 188 



Willemite; Zincite or red oxide of zinc; Sulphide of zinc, 

sphalerite, or blende, or black jack . ." 189 

Geology of zinc, illustrated by section of strata near Sparta, 

New Jersey, zinc mines 190 

Deposits of sulphide of zinc in Colorado and Montana; Blow- 
pipe tests for zinc; Iron; Native iron; Chief ores of iron; 

Magnetite, u polaric " or loadstone 191 

Franklinite 192 

Specular ore or red hematite; Brown iron ore or brown hema- 
tite, or limonite 193 

Spathic iron ore or siderite; Black band ore 194 

Chromic iron or chromite; Iron pyrites .... .... 195 

Arsenical pyrites or mispickel; Geology of iron 196 

Geological horizon around the iron ores of Lake Superior; Geo- 
logic regions in which iron ores are found 197 

Section of Pilot Knob, Missouri; Use of the magnetic needle in 

prospecting for iron 198 

W. H. Scranton's report on the subject 199 

Method of using the compass in searching for ore 200 



Mercury or quicksilver; Formation of amalgams 202 

Cinnabar or sulphide of mercury; Metacinnabarite; Guadalcaza- 

rite; Native amalgams 203 

Quicksilver deposits of Almaden, Spain; Cinnabar at Idria, 

Austria; Quicksilver-bearing belt of California 204 

Bismuth 205 

Nickel; Examination of nickel under the blow-pipe; Chief ores 

of nickel; Smaltite; Nickel arsenide, "copper nickel" or 

niccolite 206 

Emerald nickel; Millerite 207 

Sources of nickel at Sudbury, Canada; Foleyrite; Whartonite . 208 
Jack's tin or blueite; Analysis of ores for nickel and cobalt; 

Separation of lead 209 

Separation of copper 210 

Precipitation of the iron 211 

Construction of a hydrogen apparatus 213 

Separation of nickel and cobalt 215 



Garnierite and its localities; Cobalt 217 

Smaltite; Cobaltite; Erythrite 218 

Linnseite; Earthy cobalt, or cobalt wad, or asbolite; Geological 

position of cobalt 219 

Cadmium; Greenockite 220 



Aluminium and its distribution; Minerals which serve as the 

sources of the metal 221 

Bauxite and its purification for the purpose of aluminium manu- 
facture 222 

Cryolite 223 

Corundum and emery 224 

Varieties of corundum; Localities for corundum in the United 

States 225 

Chief European sources of emery; Test for the quality of a 
sample of emery or corundum; Antimony and the forms in 

which it occurs 226 

Stibnite and its occurrence in the United States 227 

Manganese; Classes of manganese ores; Wad; Pyrolusite . . . 228 

Psilomelane; Manganese carbonate or rhodochrosite 229 

Geological position or manganese 230 



Alum; Apatite or phosphate of lime 231 

Coprolites 232 

Arsenic; Native arsenic; Realgar 233 

Orpiment; Asbestus; Barytes 234 

Witherite; Borax . . 235 

Clays; Classes of soft clays; Kaolin, porcelain clay, or China 

clay 236 

Pottery or plastic clay; Bole; Fuller's earth; Coal (mineral) . . 237 
Anthracite (glance coal, stone coal); Bituminous coal; Brown 

coal or lignite; Jet; Dolomite 238 

Feldspar, orthoclase; Adularia; Moonstone; Sunstone; Aven- 

turine; Amazon stone 239 



Flint; Hornstone or chert; Fluorspar, fluorite; Graphite, plum- 
bago, or black lead 240 

United States localities for graphite 241 

Mode of testing the purity of graphite; Gypsum 242 

Alabaster; Satin spar; Plaster of Paris; Infusorial earth; Litho- 
graphic limestone 243 

Meerschaum or sepiolite; Micas 244 

Biotite or black mica; Muscovite or potash mica; Molybdenum. 245 

Nitre or saltpetre; Rock salt 246 

Occurrence of salt deposits; Deposit of rock salt in Petite Anse 

Island, Louisiana 247 

Slate; Sulphur 249 

Method of estimating the sulphur available to tha acid maker 

in a sample of pyrites; Talc, soapstone, or steatite 250 



Occurrence of crude petroleum; Outfit and best time of the year 
for prospecting 252 

Examination of the iridescent film on the surface of water; In- 
dication of an outcrop of oil . . . 253 

Tracing the source of the oil; The water test; Fresh fracture of 
oil-bearing sandstone 254 

Color of traces of oil upon the surface of water in cooler weather ; 
Iridescent films in swampy puddles 255 

Salses (mud volcanoes) and exhalation of natural gas as an in- 
dication of petroleum; Occurrence of oil in definite geological 
horizons 256 

Occurrence of oil in beds or in veins; Tracing a thick seam or 
stratum of oil-bearing sandstone; Outcrops in a large mass of 
sandstone. 257 

Data to be made in the sketch-map when promising out-crops 
of oil have been found, illustrated .... 258 

Vein-like occurrence of oil, described and illustrated .... 259 

Occurrence of oil in a maze of smaller and larger fissures . . . 260 

Quality of the oil; Ozocerite and its occurrence; Ozocerite de- 
posit in East Galicia, described and illustrated 261 

Mineral resins closely allied to ozocerite 262 

Retinite; Elaterite; Pyropissite; Properties of ozocerite . . . 263 



Native asphalt or bitumen; Most remarkable deposits of as- 
phalt; Asphalt in California and other portions of the United 
States 264 

Peat 265 



Occurrence of gems and precious stones in the United States; 

Comparatively little value of many gems 266 

Occurrence of diamonds and gold in the same alluvial deposit. 267 
Use of the dichroiscope in distinguishing gems . . . . 268 

Diamond; Occurrence of diamonds in India, and in Borneo . • 270 
Diamonds in Brazil; Carbonado or black diamond; Minerals 

associated with the diamond in South Africa 271 

The diamond-bearing ground at the Kimberley Mine, South 
Africa; Occurrence of the diamond in the Ural, Australia, 

New Zealand, and in the United States 272 

Natural surface of the diamond ; Color of the diamond .... 273 

Properties of the diamond 274 

On what the value of the diamond depends 275 

Some of the largest diamonds, illustrated ; The Koh-i-noor ; 
The Orloff; The Grand Duke of Tuscany or Florentine; The 

Pitt or Regent; Sapphire . . 276 

Ruby and its varieties ... 277 

Topaz and localities for it in the United States 278 

Beryl or emerald; Phenacite 279 

Zircon; Garnet and localities for it in the United States . . . 280 

Tourmaline 281 

Epidote; Opal and its varieties 282 

Turquois, and localities for it in the United States 283 

Agate and its varieties 284 

Chalcedony; Chrysoprase; Carnelian and sard; Jasper; Blood- 
stone or heliotrope . 285 

Rock crystal ; Amethyst ; Rose quartz; Smoky quartz; Yellow 

or citron quartz, or false topaz . 286 

Onyx and sardonyx; Cat's eye; List of gem-stones compiled by 

Mr. George F. Kunz 287 

List of gem-stones known to occur in the United States .... 288 



List of species and varieties found in the United States, but not 
met with in gem form ; List of species and varieties not yet 
identified in any form in the United States ; List of gem- 
stones occurring only in the United States 289 

Table of characteristics of gems 290 


Prospecting by means of electricity 293 

Weights and measures ; Basis of British weights and measures. 295 
Weights and measures of various nations; English length ; Par- 
ticular measures of length; Surface measure 296 

Surface measure in feet; Solid measure; Troy weight; Avoirdu- 
pois weight; Weight by specific gravity; Method of finding 

the weight of masses without the use of scales 297 

How to find the specific gravity 299 

Special weights, etc > . . 300 

French measure; Length; Surface; Solid measure; Weight . . 301 
Specific gravity of metals, ores, rocks, etc. ; Ores associated with 

gold and silver; Other ores 302 

Specific gravity of minerals of common occurrence; Average in 

cubic feet of a ton weight of various materials 303 

Assay of gold by the touchstone . 304 

Estimation of gold in alloys 305 

Standard value of gold in different countries; Power for mills . 307 

Boring; Diamond drill 308 

The chemical elements, their symbols, equivalents and specific 

gravities £09 

To find the proportional parts by weight of the elements of any 
substance whose chemical formula is known; Common names 

of chemical substances 311 

Prospectors' pointers 313 

Glossary of terms used in connection with prospecting, mining, 

mineralogy, geology, etc . 315 

Index 3£5 





It is well-known that much disappointment and 
loss accrue through lack of knowledge by prospec- 
tors, who, with all their enterprise and energy, are 
often ignorant, not only of the probable locality, 
mode of occurrence and widely differing appearance 
of the various valuable minerals, but also of the 
best means of locating and testing the ores when 
found. It is a well-established fact that the major- 
ity of the best mineral finds have been made by the 
purest accident, often by men who had no mining 
knowledge whatever, and that many valuable dis- 
coveries have been delayed, or, when made, aband- 
oned as not payable from the same cause — ignor- 
ance of the rudiments of mineralogy and mining. 
Hence in preparation for skilled work, the prospec- 
tor should have become thoroughly acquainted with 
the forms under whicli\useful minerals and metals 

This should be his very first study. . It may be 
called the study of 


By a mineral is meant any chemically homogene- 
ous substance which neither forms, nor retains any 
traces of having formed, part of an organized being, 
and which has not been produced by the applica- 
tion of physical forces by man. The properties of 
minerals are numerous. Some, such as the form, 
bulk, hardness, color, etc., are readily perceived ; 
while others such as the chemical nature, crystalline 
structure, behavior towards light and heat, are not 
so apparent, and can only be determined by means 
of a systematic investigation. The value of these 
properties in affording distinguishing characters 
differs greatly, but the most important are chemical 
composition, crystalline form, and density. 

When two or more minerals occur together and 
form large masses, they constitute rocks. 

The minerals which are the principal constituents 
of rocks are the following : 

1. Those containing silica: as quartz; the feld- 
spars ; the micas ; hornblende ; pyroxene ; talc ; 
serpentine ; chlorite. 

2. Carbonates : as carbonate of lime or calcite ; 
carbonate of lime and magnesia or dolomite. 

3. Sulphates: as sulphate of lime or gypsum. 
The special characteristics of these, and of other 

less frequent mineral constituents may be learned 
from a text book on mineralogy. The following are 


the prominent characters of the most common kinds 
concerning the prospector : 

Quartz. Occurs in crystals ; also massive with 
a glassy lustre. It is too hard to be scratched with 
a knife. It varies in color from white or colorless 
to black, and in transparency, from transparent 
quartz to opaque. It has no cleavage, that is, it 
breaks as easily in one direction as another like 

There are many varieties of quartz, of which may 
be mentioned : Limpid quartz, clear and colorless ; 
amethyst, violet crystals ; agate, presenting various 
colors arranged in parallel bands, straight, curved, 
or zigzag ; chalcedony, transparent or translucent, 
and varying in color from white to gray, blue, 
brown and other shades ; flint, massive, dark and 
dull color, edges translucent ; hornstone, resembles 
flint, but differs from it in being more brittle, in 
breaking with a splintery, uneven fracture, and in 
not being so hard as quartz ; basanite, Lydian stone, 
or touchstone, velvety black, more opaque than horn- 
stone. It is used for trying the purity of gold. 

Opal is also a form of silica. 

Feldspar. This name is given to a group of 
minerals which are inferior to quartz only as a con- 
stituent of rocks. They have a lustre nearly like 
quartz, but often somewhat pearly on smooth faces, 
are very nearly as hard as quartz, with about the 
same specific gravity (2.4 to 2.6); and in general 
have light colors, mostly white or flesh-colored, 
though occasionally dark grey, brownish or green. 

They differ from quartz in having a perfect cleav- 
age in one direction, yielding under the hammer a 
smooth lustrous surface and another nearly as per- 
fect in a second direction inclined 84° to 90° to the 
first ; also in being fusible before the blowpipe, 
though not easily so ; also in composition, the feld- 
spars consisting of silica combined with alumina 
and an alkali — this alkali being either potash, soda, 
or lime, or two or all of them combined. Included 
in this group are a number of distinct kinds or 
species. These species differ in the proportion of 
silica (the acid) to the other ingredients (bases), and 
in the particular alkali (potash, soda, or lime) pre- 

The most important kinds are : 

Orthoclase, or common feldspar, a potash feldspar. 
The cleavages make a right angle with one another, 
whence the name, signifying cleaving at a right 

In the following kinds the cleavages make a right 
angle with one another of 84° to 87° and hence 
they are sometimes called anorthic feldspars or 
plagioclastic feldspars. 

Albite, a soda feldspar, colorless and transparent, 
or translucent, and various shades of red, yellow, 
green and gray. 

Oligoclase, a soda-lime, the soda predominating. 
Color, generally whitish or grayish with shades of 
green and yellow. 

Labradorite, a lime soda, often iridescent. Color, 
usually ash or greenish gray, but frequently various 


shades of green, yellow, and red, and sometimes the 
smaller crystals are colorless. 

Anorthite, a lime feldspar, transparent and color- 
less, or translucent and greyish or reddish. 

Feldspars are essentially constituents of volcanic 
and crystalline igneous rocks, orthoclase being 
typical of granite, syenite, gneiss and trachyte, 
usually in association with quartz. 

Labradorite is the feldspar of basalts and doler- 
ites in microscopic crystals, and it also forms 
enormous rock masses in Labrador. Oligoclase may 
be associated with orthoclase in granite, and is the 
feldspathic constituent of diorite and diabase. An- 
desite is the feldspar of the trachytes of the Andes. 
Albite is chiefly found in crystalline schists and also 
in granite veins. Anorthite is best developed in 
the crystalline limestone blocks of Vesuvius, and 
also occurs in some basalts. 

Micas. This embraces a group of minerals 
whose most marked common feature is a highly 
laminated structure, and they admit of being split 
into leaves even thinner than paper. They are 
colorless to brown, green, reddish and black, and 
occur either in small scales disseminated throughout 
rocks — as in granite — or in large plates. The 
micas are silicates of alumina with either potash, 
magnesia or iron and some other ingredients. 

The most important species of mica are : 

Muscovite. This is the common mica which in 
the form of clear or slightly smoky colored plates is 
used in the doors of stoves and lanterns. In Russia 

6 prospector's field-book and guide. 

it was used for the windows of houses and this gave 
the name to the mineral of Muscovy glass, whence 
the mineralogical name of muscovite. 

Muscovite is a potash mica usually occurring in 
rhombic or six-sided tabular crystals. In many 
rocks the crystals are but poorly developed or only 
represented by irregularly shaped scales ; cleavage 
basal and very perfect ; color, mostly silvery white, 
seldom, but occasionally, dark brown or black. Be- 
fore the blowpipe it whitens and fuses on thin edges 
to a grey or yellow glass. Muscovite is not decom- 
posed by sulphuric or hydrochloric acid. 

Lepidolite. Some of the potash micas contain 
lithia, and these are generally distinguished as 
lithia mica. Lepidolite is a lithia mica, the potash 
of muscovite being partially replaced by lithia. It 
is frequently a substitute for muscovite in granites. 
It usually occurs in fine scaly or granular aggre- 
gates rather than definite crystals. The color is 
generally violet, rose-red, or violet grey, and occa- 
sionally white. Lepidolite colors the flame of the 
blowpipe purple red. After fusion before the blow- 
pipe it is completely decomposed by acids, but 
otherwise it is only imperfectly soluble. 

Phlogopite, a magnesia mica of light brown or 
copper-red and sometimes white color. It is com- 
mon in limestone or in serpentine rocks and in 

Biotite. This includes most of the magnesia-iron 
mica. Color, black or dark green. Very thin 
laminae appear brown, greenish or red by trans- 


mitted light. Lustre pearly, hardness 2.5 to 3, 
specific gravity 2.7 to 3.1. The basal cleavage is 
highly perfect and the laminae are flexible and 
elastic as in other members of the mica group. It 
is only slightly acted upon by hydrochloric acid, 
but is decomposed by sulphuric acid, leaving a 
residue of glistening scales of silica. Biotite is the 
second most important mica. 

Lepidomelane is an iron-potash mica. It occurs 
in small six-sided tabular crystals, or in aggregations 
of minute scales. Color, black ; lustre adamantine 
or somewhat vitreous. Easily decomposed by 
hydrochloric acid, leaving a fine scaly residue of 

Lepidolite or lithia mica resembles muscovite in 
crystalline form and many of its physical properties* 
Its color is white, yellowish or rose red, the last be- 
ing very prevalent. It fuses before the blowpipe 
more readily than muscovite, and is decomposed by 
hydrochloric and sulphuric acids but not so readily 
as the magnesian micas. Lepidolite is most com- 
monly met with in metalliferous veins, especially 
those containing tin, and is nearly always associated 
with other minerals which contain fluorine, such as 
fluorspar, topaz, tourmaline, and the emerald ; it is 
also frequent in many kinds of granite. 

Amphibole, often called Hornblende. The 
most common kind is an iron-bearing variety, in 
black cleavable grains or oblong black prisms cleav- 
ing longitudinally in two directions inclined to one 
another 124° 3 0'. It occurs also in distinct prisms 


of this angle, and of all colors from black to green 
and white. 

Actinolite is the name applied to the green variety, 
and besides lime and magnesia, contains also iron. 
It occurs often in fibrous or columnar masses, some- 
times with a radiated structure. 

Tremolite is a lime-magnesia hornblende. The 
pure crystals are white, but the impure ones are 
yellowish or greenish gray owing to the presence of 
protoxide of iron. There are several varieties of 
tremolite. Thus the substance known as 

Asbestus * is in most cases tremolite containing a 
little water. It generally occurs in fine fibres which 
may be isolated or packed closely together with 
their principal axes parallel. 

Mountain leather is a similar mineral, but the 
fibres are finer, closer and intermixed. 

Mountain cork is a spongy, elastic asbestus, with 
the fibres interlaced together. 

Mountain wood is like the last, but denser, far less 
elastic and capable of taking a high polish. 

Nephrite or oriental jade is a compact variety 
much used by the Chinese as a figure stone. The 
color is sometimes light green as in the white jade ; 
and olive green, as in the green jade. It has an un- 
even, fine-grained fracture, and a greasy lustre. 

Tremolite is found in many places, but nearly 

*Most of the asbestus mined for use in the arts is a fibrous 
variety of serpentine, and is easily distinguished because it con- 
tains about 14 per cent, of water. 


always in the older dolomites and saccharoidal 

Pyroxene, including augite. Like hornblende 
in most of its characters, its varieties of colors and 
its chemical composition. But the crystals instead 
of being prisms of 124° 30', are prisms of 87° 5'. 
Black and dark green pyroxene in short crystals is 
called augite. It is an iron-bearing kind and is 
common in igneous rocks. 

The minerals of the amphibole group closely re- 
semble pyroxene in chemical composition, while 
they also crystallize in the same system. They 
differ, however, in the angular measurements of the 
oblique rhombic prism, which, as already shown, 
in hornblende is 124° 30', and in augite 87° 5' to 
92° 55'. 

They are all bisilicates of protoxides and sesqui- 
oxides, the former being lime, magnesia, soda, 
potash, and the protoxides of iron and manganese, 
while the latter are represented by alumina and the 
protoxides of iron and manganese. 

Crystals of amphibole differ from those of pyrox- 
ene, not merely in the angular measurements of 
their oblique rhombic prisms, but also in the 
angles at which their cleavage planes intersect. 
This circumstance is of considerable value to the 
mineralogist, since it is often difficult or impossible 
to measure the angles of the actual crystallographic 
faces, but is generally possible to measure the angles 
of cleavage. The crystals of minerals belonging to 
the amphibole group usually exhibit a fine longi- 
tudinal striation. 

10 prospector's field-book and guide. 

Color affords no safe means of discriminating 
between pyroxene and amphibole, since the mem- 
bers of both groups exhibit greenish and brownish 
tints. The augites and hornblendes which occur 
in basalt are mostly brownish in color. 

The hornblende in syenite is also generally 
brown, but that which occurs in phonolite is mostly 
of a greenish tint, while the augite in leucite lavas 
is, as a rule, also green. 

The minerals of the amphibole group frequently 
show a tendency to develop long blade-like crystals. 
This tendency is in a very marked degree shown by 
actinolite, one of the principal varieties of amphi- 
bole, the crystals arranging themselves in radiate 

Both hornblende and augite occur together in the 
same rock, but as a rule the former mineral is found 
in those rocks which contain a large percentage of 
silica, the associated minerals being usually quartz 
and orthoclase, while augite is generally found in 
rocks of a basic character containing tri clinic feld- 
spars, and with little or no free silica. 

Chlorite, occurs sometimes in thin, foliated 
plates like mica, but inelastic, oftener granular, 
massive ; sometimes in green crystals and scales. 
These kinds of chlorite are found in rocks and form 
the mass of chlorite rock and chlorite slate. 

The chlorites are silicates of alumina, iron and 
magnesia with water, the average percentage of 
magnesia being about 34 and that of water over 12. 

Chlorite is a very soft mineral and is essentially 
a product of the decomposition of other minerals. 


When heated in a glass tube it gives off water. 
Before the blowpipe it exfoliates, whitens and melts 
with difficulty into a greyish enamel. It is soluble 
in hydrochloric acid when powdered, and after long 

Talc. A hydrated silicate of magnesia from 
which the water is only driven off at a high tem- 
perature. It generally occurs in broad pale green 
or silvery whitish plates or leaves, looking like 
mica, but the cleaved plates, though flexible, are 
much softer and not elastic. It is easily scratched 
by the nail, has a pearly lustre and is soapy and 
unctuous to the touch. Before the blowpipe it 
turns white and exfoliates. It is neither before or 
after ignition soluble in either hydrochloric or sul- 
phuric acid, thus differing from chlorite. 

Serpentine. This is also a hydrated silicate of 
magnesia. It is usually compact, massive, not 
granular at all, of a dark green color, but varying 
from pale green to greenish black. The most 
peculiar variety is a fibrous kind occurring in 
seams in massive serpentine, which is called 
crysotile, popularly called asbestus. 

Minerals are composed of chemical elements, 
which are substances which cannot be further sepa- 
rated. A table of the chemical elements, their synr 
bols, equivalents and specific gravities, is given in 
the Appendix. When these elements unite together 
and form a compound, they always do so in fixed 
proportion and in definite weight. Therefore, in 
any pure mineral, whose composition is known, the 

12 prospector's field-book and guide. 

amounts of the elements going to make up any 
given mass of it can be calculated by a rule of 
three sum. 

For example, in galena (PbS) we have lead (Pb) 
= 207 and sulphur (S)=32, total 239. Therefore, 
in 239 lbs. of pure galena we will find 207 lbs. of 
lead (86J per cent.), and so on in proportion. 

Thus any mineral that is pure enough to be 
weighed directly, or which can be concentrated pure 
and then weighed, can be estimated in this way, and 
the percentage content of the ore calculated. 

The combination of two or more of these elements 
together gives rise to three classes of substances, 
namely, acids, bases, and salts. 

Oxides of non-metallic elements are acid. 

Oxides of metallic elements are bases. 

Where an acid and a base unite, one exactly 
neutralizing the other, a substance is produced hav- 
ing neither acid nor basic tendency. It is known 
as a salt. 

Most minerals are salts. There is only one com- 
mon acid mineral, namely, quartz (S 2 2 ), or the 
oxide of the non-metallic element silicon. 

There are many minerals which are basic, such as 
hematite (Fe 2 3 ) and magnetite (Fe 3 4 ), the oxides 
of iron, and cuprite (CuO), the oxide of copper. 

Among the many minerals which are salts are 
common salt or sodium chloride (NaCl) ; limestone 
or calcite (CaC0 3 ), formed from the union of the 
oxide of calcium (metal) and carbonic acid gas ; 
gypsum (CaS0 4 2H 0), formed by the union of the 


oxide of calcium (metal) and sulphuric acid ; apatite, 
phosphate of lime [Ca 3 (P 2 4 ) 2 ] , formed by the same 
base as above uniting with phosphoric acid. 

There are a great many minerals the acid member 
of which is silica, with one or more metallic oxides 
forming the basic member. These are known as 
silicates, and feldspar, mica, hornblende, pyroxene, 
talc, serpentine, etc., are examples. 

These facts are important to remember, because 
whole families of minerals and rocks are classified 
acid or basic according to the greater or lesser 
quantity of silica present in them. 

The colors of minerals are either essential to 
them, as in the sulphides, oxides and acidiferous 
compounds of most metals, and in those species of 
which they are essential constituents ; or they are 
the effect of casual intermixture of these substances 
in species which, when pure, are naturally colorless. 
Of the latter sort are the colors of feldspar, calcspar, 
rock salt, marble, and jasper, in which the various 
tints of red and yellow are generally due to the 
oxide and hydrous oxide of iron. Other minerals 
derive a brilliant green color, some from carbonate 
of copper, others from the oxide of nickel or of 
chrome. In species of which the color is a perma- 
nent character, its intensity is often so far varied by 
a difference of texture or confused crystallization, 
that red, brown, and green substances appear, in a 
mass, to be black ; but on being pulverized, their 
true color will be seen. It is therefore advisable, 
in describing a mineral, to state what its color is 
when reduced to powder. 

14 prospector's field-book and guide. 

The intermixtures of coloring matter, which are 
merely mechanical, render a mineral more or less 
opaque ; thus the red and yellow jasper are chalce- 
dony — which when pure is highly translucent, or 
even semi-transparent — colored by minute particles 
of oxide of iron, which are themselves opaque. But 
colors, which, though they may not be essential to a 
species, are the result of chemical combination, do 
not impair its transparency ; such is the violet tint 
of amethyst, which is derived from a minute por- 
tion of the oxide of manganese combined with the 
quartz ; and the green of the emerald, which may 
in some cases be due to oxide of chrome. 

In consequence of the variable quantity of color- 
ing matter, whether chemically combined or other- 
wise, many substances present various tints and 
shades of color, so that they are particularized as 
blood red, flesh red, chestnut brown, lemon-yellow, 
sky-blue, etc. 

Accidental colors being unequally distributed, 
often produce parallel bands, either straight or 
curved, and clouded forms, as in agates. Some- 
times the color takes the form of leaves and moss, 
or runs through the mass in veins, as in marble. 

There are still other colors, which are neither 
essential to minerals, nor yet produced by intermix- 
ture. Some, as the sulphide of antimony, exhibit 
a brilliant superficial tarnish, in which the pris- 
matic colors are regularly arranged. In transparent 
substances, prismatic colors are perceived in the in- 
terior, and arise from minute cracks or fissures 


containing films or particles of air ; these are often 
movable by slight pressure. 

A very curious peculiarity of color called poly- 
chroism is connected with the phenomenon of 
double refraction. Some minerals, placed between 
the eye and the light, transmit different colors in 
different directions. Tourmalines, viewed parallel 
to their axis, are generally opaque ; perpendicularly 
to it, they appear to be green, red, brown, etc. 
This difference is not observable in all double 
refracting substances ; but in some which have two 
axes of double refraction three different tints have 
been observed. Minerals crystallizing in the cubic 
system never transmit more than one color, if their 
composition and texture be homogeneous through- 

In some minerals a peculiar light is produced 
either by friction or heating them, which is called 
phosphorescence. On rubbing together two frag- 
ments or pebbles of quartz, a faint greenish light 
will be perceived, and the same effect can be pro- 
duced with certain marbles. Other substances 
when placed on a heated shovel, emit a brilliant 
phosphorescence, which in some is green ; in others 
pale violet. The best mode of conducting this 
experiment, if the specimen is powdered, or in 
small fragments, is to strew it over a shovel heated 
nearly to redness ; but if it be an inch or two in 
length, it is better to heat it slowly, and not beyond 
the necessary degree, by which means the operation 
may be frequently repeated without injuring the 


Some metals are found native and in some degree 
of purity, as in the cases of gold, silver, copper, 
mercury, and platinum, and when so found are 
readily determined at once by any one who is at all 
acquainted with those metals as they occur in gen- 
eral use. But frequently native metals appear 
under such colors, and even forms, that the dis- 
coverer must possess more knowledge than any one 
usually possesses who has seen the metal in the arts 
only. Gold, as an illustration, is frequently found 
in various shades of yellow, in accordance with the 
amount of silver or copper it may contain, and yet 
to the practiced eye of a true mineralogist it never 
loses the true gold hue. 

Iron pyrites, which is composed of sulphur and 
iron, and called "pyrite," mineralogically, has a 
color somewhat similar to that of gold, and so also 
has a mineral called " chalcopyrite," or copper 
pyrites, which contains copper, iron and sulphur. 
These, with others, vary in the yellow shade, and 
degrees of color, but by the practiced eye are in- 
stantly detected. Of course the brittleness of these 
minerals is unlike the softness of native gold, and 
this would instantly reveal the fact that they were 
not gold ; but we are now speaking of the practiced 
eye alone, and therefore of the benefit of cultivating 
a knowledge by sight of minerals. The mode in 
which a mineral breaks when smartly struck with 
a hammer, or pressed with the point of a knife, is a 
character of importance. Many minerals can only 
be broken in certain directions, for instance, a 


crystal of calc spar can only be split parallel to the 
faces of a rhombohedron ; many crystals break more 
readily in one direction than in others. Whenever 
a mineral breaks with a smooth, flat, even surface, 
it is said to exhibit 

Cleavage which always depends upon the crys- 
talline form. But minerals often break in irregular 
directions, having no connection whatever with the 
crystalline form, and this kind of breaking is called 

Fracture. The nature of the surface given by 
fracture is often a character of importance, especially 
in distinguishing the varieties of a mineral species. 
Thus quartz and many mineral species show a 
shell-like fracture-surface which is called conchoidal, 
or if less distinct, small conchoidal or sub-conchoidal 
More commonly the fracture is simply said to be 
uneven, when the surface is rough and irregular. 
Occasionally it is hackly, like a piece of fractured 
iron. Earthy and splintery are other terms some- 
times used and readily understood. 

Streak. The color and appearance of the line of 
furrow on the surface of a mineral, when scratched 
or rubbed, is called the streak, which is best ob- 
tained by means of a hard-tempered knife or a file. 
The color of a mineral and its streak may corre- 
spond, or the mineral and its streak may possess 
different colors, or the mineral may be colored while 
its streak is colorless. For instance, cinnabar has 
both a red color and a red streak ; specular iron has 
a black color, but a red streak ; sapphire has a blue 
color, but a white colorless streak. The streak of 

18 prospector's field-book and guide. 

most minerals is dull and pulverulent, but a few 
exhibit a shining streak like that formed on scratch- 
ing a piece of lead or copper. This kind of streak 
is distinguished by the name of 'metallic. In judg- 
ing the streak of a mineral, much-weathered pieces 
should be rejected. 

Hardness is another character of great impor- 
tance in distinguishing minerals ; it is the quality of 
resisting abrasion. The diamond is the hardest sub- 
stance known, as it will scratch all others. Talc is 
one of the softest minerals. Other minerals possess 
intermediate degree of hardness. To express how 
hard any mineral is, it becomes necessary to com- 
pare it with some known standard. Ten standards 
of different degrees have been chosen, and are given 
in order in the following scale : 

1. Talc, easily scratched by the finger-nail. 

2. Gypsum, does not easily yield to the finger- 
nail, nor will it scratch a copper coin. 

3. Calcite, scratches a copper coin, but is also 
scratched by a copper coin. 

4. Fluorite, is not scratched by a copper coin, and 
does not scratch glass. 

5. Apatite, scratches glass with difficulty ; is 
readily scratched by a knife. 

6. Feldspar, scratches glass with ease ; is difficult 
to scratch by a knife. 

7. Quartz, cannot be scratched by a knife, and 
readily scratches glass. 

8. Topaz, 

9. Corundum, 

> harder than flint or quartz. 


10. Diamond, scratches any substance. 

If on drawing a knife across a mineral it is im- 
pressed as easily as calcite, its hardness is said to 
be 3. If a mineral scratches quartz, but is itseif 
scratched by topaz, its hardness is between 7 and 8. 

In trying the hardness of a mineral, a sound por- 
tion of the mineral should be chosen and a sharp 
angle used in trying to scratch. A streak of dust 
on scratching one mineral with another may come 
from the waste of either, and it cannot be deter- 
mined which is the softer until after wiping off the 
dust and examining with a lens. 

By the test of hardness, clear distinctions may be 
drawn between minerals which resemble each other. 
Iron pyrites and copper pyrites, for instance, are 
similar in appearance, but copper pyrites can easily 
be scratched with a knife, while iron pyrites is 
nearly as hard as quartz and the knife makes no 
impression upon it. 

Flexibility and elasticity. Some minerals 
can be readily bent without breaking, for instance; 
talc, mica, chlorite, molybdenite, native silver, etc. 
Minerals which after being bent can resume their 
former shape like a steel spring, are called elastic, 
for instance, mica and elaterite. A remarkable in- 
stance of flexibility, even combined with elasticity, 
amongst the rocks, is that of a micaceous sandstone 
cailed itacolumite, which in Brazil is the matrix 
of the diamond. 

Smell. A few minerals only, like bitumen, have 
a strong smell which is readily recognized, but 

20 prospector's field-book and guide. 

specimens generally require to be struck with a 
hammer, rubbed, or breathed upon before any smell 
can be observed. Some black limestones have a 
bituminous odor, while some have a sulphurous, 
and others a foetid, smell. Hydraulic limestone 
has a smell of clay which can be detected when the 
mineral is breathed on. Some minerals containing 
much arsenic, for instance mispickel, smell of garlic 
when struck with a hammer. 

Taste. Only soluble minerals have any taste, and 
this can only be described by comparison with well- 
known substances, for instance acid, vitriol ; pungent, 
sal ammoniac ; salt, rock salt ; cooling, nitrite ; astrin- 
gent, alum ; metallic astringent, sulphate of copper ; 
bitter, sulphate of magnesia ; sweet, borax. 

Malleability. Malleable substances can be 
hammered out without breaking, and it is on this 
quality that the value of certain metals in the arts 
depends, for instance, copper, silver, gold, iron, etc. 

A few minerals are malleable, and at the same 
time sectile, i. e., they can be cut with a knife, for 
instance, silver glance, horn silver and ozokerite. 

Mineral caoutchouc (elaterite) is sectile, but like 
india rubber, can only be shaped when hot. The 
elasticity of elaterite is so characteristic that the 
mineral will be readily recognized. 

Ductility, or the capability of being drawn into 
wire, is a property which is confined exclusively to 
certain metals. It is possessed in the highest degree 
by gold, which can be drawn into the finest wire, 
or rolled into leaves of such fineness that 30,000 of 
them are not thicker than an eighth of an inch. 


Lustre. The term lustre is employed to describe 
with certain adjectives, the brilliancy or gloss of 
any substance. In describing the lustre well-known 
substances are taken as the types, and such terms as 
adamantine lustre — diamond-like — and vitreous lustre 
— glassy — are used. The lustre of a mineral is 
quite independent of its color. When minerals do 
not possess any lustre at all they are described as 
" dull." The kinds of lustre distinguished are as 
follows : 

Metallic : The lustre of a metallic surface as of 
steel, lead, tin, copper, gold, etc. 

Vitreous, or glassy lustre : That of a piece of broken 
glass. This is the lustre of most quartz and of a 
large part of non-metallic minerals. 

Adamantine: This is the lustre of the diamond. 
It is the brilliant, almost oily, lustre shown by 
some very hard materials, as diamond, corundum, 
etc. When sub-metallic it is termed metallic ada- 
mantine, as seen in some varieties of white lead ore 
or cerussite. 

Resinous or waxy : The lustre of a piece of rosin, 
as that of zinc blende, some varieties of opal, etc. 
Near this, but quite distinct, is the greasy lustre, 
shown by some specimens of milky quartz. 

Pearly or the lustre of mother-of-pearl. This is 
common where a mineral has very perfect cleavage. 
Examples : Talc, native magnesia, stilbite, etc. 

Silky, like silk. This is the result of fibrous 
structure, as the variety of calcite (or of gypsum) 
called satin spar, also of most asbestus. 

22 prospector's field-book and guide. 

Specific gravity. Prospectors soon acquire 
some proficiency in testing the weight of minerals 
by handling them. A lump of pyrite, for instance, 
can readily be distinguished from gold by its weight, 
since a mass of gold of the same size would weigh 
at least three times as much, and a little practice 
with well-known substances will enable the pros- 
pector to class most minerals within certain broad 
limits by weighing them in the hand. 

The specific gravity of a mineral is its weight 
compared with water at a standard temperature and 
pressure, which is taken as the standard, and de- 
scribed as having a specific gravity of 1 ; conse- 
quently, to determine that of a mineral, it is neces- 
sary to find the weight of a piece of the mineral and 
that of a corresponding bulk of water, and to divide 
the first by the last. This can be done with great 
accuracy in the laboratory, where delicate balances 
are available, but is not applicable in the field, when 
the most that can be undertaken is to class minerals 
roughly within certain broad limits, and indeed, 
this is generally sufficient for the prospector. Some 
rules for finding weights by specific gravity are 
given in the Appendix. 

What has previously been said of color may also 
be said of weight and form. A lump of pyrite in 
the hands of a skilled mineralogist would be dis- 
tinguished from gold by its weight, since as above 
mentioned, a mass of gold of the same size would 
weigh at least three times as much. Three crystal- 
line pieces, the one of barite, the other two of lime 


carbonate and of quartz, may to the unskillful eye 
appear equally transparent ; but the form of the 
first is tabular, that of the latter two is in six-sided 
crystals, but the lime carbonate crystals terminate 
in three sides, while the quartz always (like the 
sides) in six. 

Besides a knowledge of the forms under which the 
minerals we seek present themselves, it is also neces- 
sary to learn the characteristics of some of the rocks 
which are generally associated with those minerals. 
The object of this knowledge is to serve in directing 
us to those regions where we may with greater prob- 
ability discover the minerals we seek. It also serves 
to w T arn us out of a region where we should not 
expect to find what we desire. 

To illustrate, we may not expect to find iron ores 
of a certain kind, brown hematites for instance, in a 
granitic country. On the other hand, we may find 
the magnetic ores in such a region, and it is useless 
to explore a granitic region for black band iron ore, 
although it may be the proper region to discover 
red hematite. 

It is, therefore, important that the prospector 
should be able to distinguish many of the geologic 
rocks to help in guiding or in checking him, in his 

A general knowledge, therefore, of the manner in 
which the geologic rocks are " laid down," their 
order, or succession, in the earth, is important, and 
the distinction between sedimentary and that which 
has been, and is usually called " igneous rock," but 



more properly " azoic rock," that is, rock which 
does not exhibit any remains of fossil or organic 
life. For often the only signs by which we can, 
with any degree of certainty, determine what is the 
name of the sedimentary rock is by finding the re- 
mains of former life, that is, the kind of fossil it 
contains. Prof. Dana says (The Amer. Journal of 
Science, Nov. and Dec, 1890) that it is settled that 

Fig. 1. 

Section showing contorted strata due to lateral pressure: aa," anti- 
clinal axis ; " c, the " synclinal axis." The direction of the arrows, ee, ee, is 
that of " the strike." That of the arrows, dd, is that of "the dip" of the 
strata, always measured from the horizon ; gg, are the out-crops. 

the kind of rock in itself considered is not a safe 
criterion of geological age. 

If all the rocks in the world had been laid down 
in regularly horizontal sequence and had always re- 
mained in their own separate " horizons," as every 
rock of the same age is called, not only should we 
find them all parallel, one over the other, but we 


might readily determine to some extent what were 
the exact order and distance of any one horizon, or 
geological age. But, although there is a general 
order, the same in all parts of the world, there have 
been upheavals and sinkings, dislocations and ero- 
sions, during the ages, so that it is necessary that 
the prospector should become acquainted with the 
various changes probable in the order and forms of 
the vast rocks which carry the minerals for which 
he is seeking. 

Some of these movements of the earth's crust are 
represented in Fig. 1. 


We repeat that it is of considerable importance 
that the prospector should have at least some general 
knowledge of those geological horizons with which 
his work is specially associated. As we have inti- 
mated, useful minerals do not always confine them- 
selves to one horizon ; but there are certain ranges 
of rock which indicate their vicinity. There are 
also limits which are never overpassed by some use- 
ful minerals, and experience has shown that some 
horizons are always sterile in ores, and it is there- 
fore useless ever to expect to find them in paying 
quantities, in certain rocks or beyond them in cer- 
tain directions. 

Gold often occurs where it will not pay to 'open 
and work the strata, so also with lead and copper. 
It is well to learn the relations of such barren 
regions, or horizons, as the strata are called. 

26 prospector's field-book and guide. 

In the following table we have given chief place 
to these horizons which have been found in our 
own country to abound in the useful minerals, and 
we advise the possession of small specimens of the 
principal rocks mentioned and the special examina- 
tion of the specimens under a good lens, so as to 
become thoroughly acquainted w T ith their appear- 
ance and their minute parts of composition. 

All rocks may be classified as — 

1. Igneous. 

2. Metamorphic. 

3. Aqueous. 

Speaking geologically, not only the hard consoli- 
dated, massive and stony substances are called 
" rocks," but any natural deposits of stony material 
such as sand, earth, or clay, when in natural beds, 
are geological rocks. Very few of the rocks of this 
earth, at any rate so far as examined, are in their 
original and primal condition. Even the granites 
and volcanic rocks are composed of other and more 
ancient material disintegrated, ground up, or worn 
down, settled, buried, and compressed by ages of 
enormous pressure, or consolidated by cementation. 
Some have been "laid down" under water, having 
been disintegrated into dust, carried by the winds of 
ages out over the oceans and seas, and settled down 
into the form of the present rocks, which afterward 
have been lifted up into mountains and plains above 
the seas. But by the transporting power of rivers 
or currents in ancient oceans, and because of un- 
equal upheaval of some regions where subterranean 


forces were greater than at distant places, very large 
differences in the nature of the deposit have occurred, 
even in limited regions. These special and limited 
forces will account for the fact that although, taking 
the geological horizons throughout the world, there 
is a general sameness, differences do occur, and 
important members of the order of succession are 
omitted in some regions, and exceptions to general 
rules occur. 

In the table following are therefore given those 
universally accepted relations of certain rocks, one 
to another, in the great geologic arrangement of the 
world, omitting some of the subsidiary, limited, 
and unimportant horizons. 

1. IGNEOUS ROCKS are such as have been sub- 
jected to sufficient heat to melt the ingredi- 
ents. Of these rocks — 

Volcanic rocks are those which have been cooled 
near or at the surface, as lava, etc. 

Trachyte : A grayish rock of rough fracture ; the 
same specific gravity as quartz, but mainly 
constituted of grains of glassy feldspar. It 
is essentially a unisilicate of alumina, with 
10 to 15 per cent, potash, a little soda and 
lime ; differs from quartz in that it fuses 
before the blow-pipe, while quartz remains 
unfused except when soda is used. 

Basalt : Blackish or dark brown. Traps, green- 
stone, dolerite, amydolite; these latter four are 
only modifications, being all unisilicates with 

28 prospector's field-book: and guide. 

smaller amounts of potash than in trachyte, 
a little more soda and lime, and some traces 
of iron and magnesia, varying in color and 
Obsidian is a glass, something like bottle glass, 
of a dark shade, and translucent. 
All these are compact in texture except where 
some holes have been worn in by steam or gases. 
They are frequently found penetrating several strata, 
having been forced up in columns almost vertically, 
and sometimes spreading out horizontally for many 
miles between the strata or on the surface, and are 
called volcanic dykes, or intrusive rocks or lava. 
These and such-like are igneous rocks. 

It is not certain that granite rocks are of igneous 
origin, but they seem to belong to the metamorphic 

2. METAMORPHIC ; these are of igneous, subse- 
quently to the time when they were of aque- 
ous origin, and have undergone a change 
through pressure and heat, and, perhaps, in 
connection with steam or water. Of this 
class are the following : 

Gneiss, having a composition of small pieces of 
feldspar, mica, and quartz, like some gran- 
ites, but laminated or foliated in form, and 
not equally solid, homogeneous, and contin- 
uous throughout its structure as granite is. 

Mica Schist. This term is given to those 
laminated rocks composed of mica and quartz 




■ — 





All its shells and bones 
are of existing species. 

About 50 per cent, of ex- 
isting species of shells. 

Contains 80 per cent, of 
extinct species. 

Contains fresh water and 
marine strata, animals all 








Cha^^h^tCs"" 118 ' bUt the L0W " } se^urc^nfetf mati °" D M * S ^^ """"«""• 
Contains Greensand in England and in New .Tmsev, used as a marl and fertilizer There is a 
supposed Cretaceous lignite in Alaska, Colorado, California. Utah, etc. 





Consists of sand, clay, or marl, the sand used in glass making. 

Portland Stone. 

Oxford Group. 

Stonesfield Slate. 

Some English coal is found in the Oolite. Kimmeridge clai is founi 1 In upper Oolite ; tho flno 

Bavarian lithographic stone in the middle Oolite. 


Limestone in horizontal 

Conspicuous for the number of ammonites and nautilus shells. Furnishes building and paving 





Called by the Germans TRIAS. 

Connecticut river sandstone with footprints. 

Red clays, marls, shales and sandstones. The New Red Sandstone of Knghind. 

In Europe great salt beds. 


Dark red sandstone. 
Magnesian limestone. 
Conglomerates, Breccias, 
Marls in all three. 

Mostly sandstones and marlytes, some impure magnesian limestone and gvpsuin. 'I'Ium > .on. 

of coal,' unworkable. With exception of BROWN HEMATITE iron ore and the tali a tiei 

above, all the other metals are found in the formations below. 





Seams of Anthracite and 
bituminous coals of vary- 
ing thickness. 

Millstone grit. 

The black band iron ore. Limestone from the same mineswltb the coal In Qreal Britain, bui 

not so frequently in America. Anthracite, cannel, and bituminous coal In 
sandstone, and shales, forming the " The Coal Measures." 

Affords PETROLEUM in Pennsylvania, Ohio, and elsewhere, and salines in Michigan, " 
MOUNTAIN" LIMESTONE of England. Largely of corals. 



Catskill Period. 
Chemung Period. 
Hamilton Period. 
Corniferous Period. 


Hamilton black shales produce oil; the Hamilton beds afford excellent Bo 

Corniferous called also Upper Helderberg group. 



Oriskany Sandstone. 

Lower Heldeiberg Period. 

Salina Period. 

Niagara Period. 

Salina Period supplies the salt waters of Salina and Syracuse, N. Y. 

Trenton Period. 
Canadian Period. 
Potsdam Sandstone. 

The LEAD MINES of Iowa and Wisconsin are in the Magnesian Limestone of the Canadian 


(Between pages 28 and 2<J. ) 



in small particles, easily broken up, but more 
easily broken into tabular or leaf-like pieces, 
because the mica has been deposited in 
planes allowing of cleavage. 

3. THE AQUEOUS KOCKS are simple water 
rocks — that is, rocks composed of sediments 
from the dust or ground-up remains of other 
rocks. The presence of such sediments is 
due to the transporting power of rivers, 
floods, or currents, and also of winds and 
storms and other agencies, carrying the dust 

Fig. 2. 


to the ocean waters where it was arrested 
and became a sediment. 
In sandstone (Fig. 2), the grains of sand are 
rounded, having no sharp edges as in granite. 

Where the sedimentary material was exceedingly 
dust-like, it sometimes is laid down as fine mud and 
frequently in lamina, as in shale (Fig. 3). 

Granite is a term descriptive of rocks generally 

30 prospector's field-book and guide. 

composed of quartz, feldspar and mica, in grains 
(hence the name) of a crystalline form. But the 
granites are not all alike in the amount of either of 
the above-mentioned minerals, nor are they alike in 
color. Some granites contain no mica, as in graphic 
granite, only quartz and feldspar, and the quartz in 
the feldspar resembling written characters. Others 
contain hornblende as well as mica, or in the 
place of mica ; the hornblende being in dark or 
black crystalline specks, pieces, or crystals, and 

Fig. 3. 


consisting essentially of silica, magnesia, lime, and 
iron. This granite is called syenite granite. Where 
the feldspar is in dictinct crystals in compact base, 
and sometimes lighter than the base, which is fre- 
quently reddish, purple, or dark green, it is a por- 
phyritic granite. The granites are sometimes whit- 
ish, grayish, or flesh-red. They are considered as 
metamorphic and not igneous (Dana), although 
some authors still consider them to be igneous- 
They always present a crystalline grain in varying 
degrees of fineness and prominence. One form is 


given in Fig. 4, from a specimen in the author's 

This specimen contains two kinds of mica, one 
black, biotite, the other white, of silvery appearance, 
muscovite. The biotite presents in spots the appear- 
ance of hornblende, and only the pen-knife point 
shows the scaly lamination of mica under the lens. 
It also contains crystalline forms of potash feldspar 
(orthoclase), distinguishable from the quartz by their 
side only, by the lamellar fracture of its edges, and 
its peculiar vitreous glimmer, for practically the 

Fig. 4. 

Granite with black mica and feldspar crystals, with quartz as chief base. 

hardness appears the same, although feldspar is (6.6 
and quartz 7) slightly softer. It would be well for 
the prospector to gather many forms of granite and 
examine them under the lens until he becomes 
throughly used to the variations. 

The first indications of a deposit possessing 
economic value are, as a rule, to be met with among 
the materials forming the beds of streams, and 
wherever water-courses have seamed and furrowed 
the rocks. Metalliferous deposits should be looked 
for in hilly districts as a general rule, though 

32 prospector's field-book and guide. 

alluvial accumulations may be found in compara- 
tively flat country. A close study of natural phe- 
nomena will often help in the discovery of mineral 
wealth. Thus the form and color of the surface; 
stained patches ; springs of water whether sweet or 
mineralized ; scum floating on water (petroleum, 
etc.); accumulations of earth brought to the surface 
by burrowing animals ; changes in vegetation ; be- 
havior of the magnetic needle. These, however, 
only serve to indicate existence without reference to 
quantity or quality. 

The valuable minerals and metal-bearing deposits 
of the earth occur as 

Lodes. By a lode or vein is generally meant a 
fissure in the rocky crust of the earth which is filled 
with mineral matter. In Australia a vein is called 
a reef and in California a ledge. The course of a 
lode in a horizontal direction is called its strike, 
while its descent is spoken of as its dip. Very often 
lodes are distinctly marked off from the rocks en- 
closing them by straight and sharp divisions on 
either side of the lode as if cut with a knife. 
These divisions are called the walls of the lode. 
When the lode inclines in its dip to either one side 
or the other, which is nearly always the case, the 
upper division is called the hanging-wall, and the 
lower the foot-wall. The incline of the lode in its 
dip is its underlie. The barren rock through which 
the lode passes is known amongst mining men as 
the " country." Lodes may be all widths from a 
thin thread-like film to 100 feet or more in width. 


Lodes often contain large blocks of the country 

Fig. 5. 



Formation, cross section. 
I, I, I, I, country rock enclosed in lode on horse, surrounded by auriferous 
quarts. A, A, hanging wall ; B, B, foot wall ; C, C, casing ; D, D, D, D, 
country rock. 

rock barren of ores or metals, which are therefore 
waste. Such occurrences are spoken of as forma- 



tions or horse, and are generally of great width 
between the two walls. See Fig. 5. 

Lodes nearly always carry casing, which is coun- 
try rock ground very fine, converted into clay by 
moisture and mixed with quartz and free native 
gold. The casing mostly occurs on the foot-wall, 
and is often very rich in metal. Fig. 6. 

Fig. 6. 

Showing solid quartz lode, with casing. Transverse section. 
1, 1, solid quartz lode without horse; 2, 2, casing of soft dig ; 3, hanging wall 
4, foot-wall ; 5, 5, country rock. 

Beds and layers. The most common of bedded 
deposits are those of coal. Many kinds of iron ore 
are found in beds, also some copper ores in shale, 
silver and lead ore in sandstone, etc. Beds and 
layers are also known as strata, measures, sills, mines, 
bassets, delfs, girdles. 


Irregular deposits, such as pockets, etc., which lie 
sometimes in various formations. Contact deposits, 
net-work of veins, and where mineral is diffused 
through rocks, or in small cracks. 

Surface deposits. By surface deposits are under- 
stood the beds of alluvium which more or less cover 
the face of every country. These beds have been 
chiefly created by various mechanical agents, which, 
after having degraded the higher rocks, carry the 
material which has thus been formed down to lower 
levels. By this process of degradation most mineral 
deposits are so comminuted that by their exposure 
to the atmosphere they are decomposed and de- 
stroyed. However, substances like cassiterite, plat- 
inum, gold, etc., not being so readily subject to de- 
composition, have, in consequence, been more or 
less preserved and buried among these superficial 
deposits. In observing deposits of this kind notice 
has to be taken of their general situation, area, 
thickness and richness. Often several beds may be 
ranged one above the other, in which case their 
relative values have to be determined. In tracing 
any particular deposit, as, for example, whilst 
ascending a valley, if the particles of ore increase 
in size and number, the prospector may expect 
that he is approaching their common origin. An- 
other indication that he is near this point of 
origin will be that he shall find the mineral less 

Comprehensively speaking, all metals are found 
in the oldest rocks only, and the latter form the 

backbone, so to speak, of the main ranges of metal- 
liferous countries. Therefore, the prospector in 
making his road towards the mountains will have 
to select a spot for starting actual operations. For 
this purpose a locality should be chosen where the 
rocks are neither too hard nor too soft, nor should 
they be of too uniform a character. The country 
most deeply indented with gullies, canons and 
gulches running parallel to one another offers the 
best chances of success. The region near the 
sources of the main rivers is generally the richest 
in metals and always the most easily prospected, re- 
quiring less labor and time in its examination, the 
loose debris and wash being of much lesser depth 
on account of the greater fall in the river and creek 
beds than at other portions of their courses. 

Auriferous lodes are most likely to be met with 
near the headwaters of river systems, and very fre- 
quently the alluvial gold begins at or near the 
locality where a number of auriferous lodes exist. 
This is a very common occurrence, and may be in 
the great majority of cases relied upon. 

When a river forks at its head into two or more 
branches, it is strange to say, the source of the gold 
will nearly always be found in the right-hand 
branch, geographically speaking. It may be men- 
tioned that in determining the right and left-hand 
branches or banks of a river or stream, you are sup- 
posed to stand at the head of the river or stream 
looking towards its mouth or outlet. Amongst 
miners this is very often reversed, and quite a num- 


ber of branches are named left-hand which, properly- 
speaking, ought to be right-hand branches. 

This right-hand theory is an old mining supersti- 
tion for which science has offered no explanation, 
but the almost unfailing applicability of the theory 
is fully established by practical experience. Speak- 
ing of mining superstitions, it may be added that 
the spots upon which the sun shines before noon 
are held by miners to be richest in metal. Every 
old gold miner will pin his faith to this theory. 
What makes these observed facts — for they really 
amount to that — all the more remarkable is, that 
they may be applied with an equal degree of liabil- 
ity to the Northern and to the Southern hemispheres, 
which makes these superstitions appear in a para- 
doxal light. However, they have survived the test 
of hundreds of years in Cornwall and on the Conti- 
nent of Europe, and have been confirmed by further 
observations in California and Australia. The latter 
instance, i. e., the spots upon which the sun shines 
before noon, may find an explanation in the fact 
that landslides and elevations of rock of all kinds 
are of more frequent occurrence upon the sunny, 
than upon the shady, side of valleys, the greater 
amount of disintegration of the rocks leading to a 
greater accumulation of the metals. However this 
may be, the theory forms one of the golden rules of 
the prospector. 

The color of the rocks also serves as a guide to the 
prospector. Rocks of a pinkish-reddish color alter- 
nating with rocks of a deep bluish tint streaked 

with drab are generally very favorable to metallic 
deposits. Another good indication is when the 
faces of the precipices are covered with a black 
ooze caused by manganese, the presence of which 
always indicates a mineralized district. These are 
simply general indications. 

Although color is always a good guide to the 
location of metallic deposits, it is of special service 
to the prospector in unexplored districts. Thus 
copper is indicated by greenish, bluish, or reddish 
stains upon the rocks in the neighborhood of the 
lode ; tin and manganese, by dull black tints, 
manganese shows itself also in pinkish streaks. 
Gold, being always accompanied with iron, mani- 
fests its presence in red, yellow, or brown shades; 
lead and silver reveal grey or bluish-grey tinges ; 
blende dyes the rocks yellowish-brown ; and iron 
disports itself in all the hues of red, yellow-brown, 
and even dun-black. 

The wash of rivers and creeks, and even more so 
that deposited upon terraces (if any) flanking the 
streams, must claim the close attention of the pro- 
spector. By wash is meant the diluvial drift in 
which gold or tin — the only metals mined in 
diluvial deposits — is found. The colors in connec- 
tion with the different metals mentioned above, 
apply also to stones and the wash generally, though 
in a modified degree. Stones streaked with pinkish 
lines, and lines indicating manganese, are always 
found in wash conveying gold. Green stones, which 
are universally found in the wash, are always a 


good indication of gold if they are of a bright sea- 
green or even pea-green, but they must be smooth, 
hard, well-polished and very heavy. In many dis- 
tricts such stones are considered the " pilot stones " 
to gold. Quartz stones must be always present in 
goodly numbers in every gold-bearing wash, and if 
they are in a decaying state, they are all the better 
as a favorable indication. 

The greater portion of the gold which has come 
into the possession of man has been obtained from 
superficial deposits, called placers. Deposits of 
placer gold are always found adjacent to and lying 
below districts traversed by auriferous veins, and 
nowhere else. The areas where the quartz veins 
occur have suffered great erosion, which has tended 
to break down and comminute the quartz, and to 
liberate and wash the contained gold. 

Placer gold is found mingled with rolled frag- 
ments of quartz and in the irregularities of the 
surface of the bed-rock where a washing process on 
a large scale has been active. 

The nuggets and coarsest gold are found nearest 
the outcrops of the quartz veins that have sup- 
plied them, while particles become gradually finer 
and finer as the line of drainage is followed from 
this point. 

Pebbles and fragments of gold bearing quartz 
which have been derived from the neighboring 
veins are commonly found in the placer deposits, 
and most of the nuggets have more or less quartz, 
like that of the veins still adhering to them. The 



gold is found in scales, grains, pebble-like nodules 
and round battered masses or nuggets. 

The domain of the prospector lies in hilly 
ground. Flat plains have little attraction for him 
except under special conditions ; because, though 

Fig. 7. 


h: ^^m^smm^ 

valuable minerals may be present, they are certain 
to be covered by an enormous deposit of soil. 

In character placer diggings manifest almost as 
great variety as vein deposits. The following illus- 
trations show in section some forms of these alluvial 
deposits : 

The stream (Fig. 7) flows across the strike of the 
rocks, and the gold is found below a hard bar ; a, 

Fig. 8. 

surface of stream ; b, mud and gravel forming bed 
of stream ; c, bed rock ; d, auriferous gravel re- 
tained by the projection of the bed rock. 



In Fig. 8, the stream flows as in Fig. 7 across 
the strike of the rocks, but the gold is found on one 
side of the creek, a, bank of stream ; b, mud and 
other worthless matter lying on the pay dirt: c, 
auriferous gravel accumulated in the deepest parts 
of the stream. 

In Figs. 9 and 10, a, represents the stream ; b, 
mud and gravel at bottom of stream ; c, bed rock ; 

Fig. 9. 

Flu. 10. 

d, pot holes in bed-rock where auriferous material 
has lodged. 

In Figs. 9 and 10, the stream generally runs 
with the strike of the rocks, or at a slight angle ; 
but the dip is nearly perpendicular in those in- 
stances where pot-holes have been known to occur. 

In estimating the value of alluvial claims it is of 
the utmost importance to consider the cheapness 
and abundance of the water supply and, which is of 


no less importance, the facilities afforded by the 
surrounding levels for the disposal of the debris of 
the mining operations or waste material, called 
tailings, from which the gold has been excavated or 
removed, so that the gold-bearing layer may be 

Indicative Plants. From very early times it 
has been noticed that the soil overlying mineral 
veins is favored by special vegetation, and though 
the occurrence of such vegetation cannot be taken 
as an infallible indication of the existence of such 
veins, it will be interesting to record the results of 
past observations, so that they may serve for a 
guidance to further observation in future. 

Indication of lead. The lead plant (Amorpha 
canescens) is said by prospectors in Michigan, Wis- 
consin and Illinois, to be most abundant in soils 
overlying the irregular deposits of galena in lime- 
stones. It is a shrub one to three feet high, cov- 
ered with a hoary down. The light blue flowers 
are borne on long spikes, and the leaves are ar- 
ranged in close pairs on stems, being almost devoid 
of foot-stalks. 

Gum trees, or trees with dead tops, as also sumac 
and sassafras, are observed in Missouri to be abund- 
ant where " float " galena is found in the clays. 

Indication of iron. A vein of iron ore near Siegen, 
Germany, can be traced for nearly two miles by 
birch trees growing on the outcrop, while the re- 
mainder of the country is covered with oak and 


Indication of limestone. The beech tree is almost 
invariably prevalent on limestone, and detached 
groups of beech trees have led to discoveries of un- 
suspected beds of limestone. 

Indication of phosphate. The phosphate miners 
in Estremadura, Spain, find that the Convolvulus 
althseoides, a creeping plant with bell-shaped flowers, 
is a most reliable guide to the scattered and hidden 
deposits of phosphorite occurring along the contact 
of the Silurian shales and Devonian dolomite. 

Indication of silver. In Montana experienced 
miners look for silver wherever the Eriogonum ovali- 
folium flourishes. This plant grows in low dense 
bushes, its small leaves coated with thick white 
down, and its rose-colored flowers being borne in 
clusters on long smooth stems. 

Indication of zinc. The " zinc violet," Galmeiveil- 
chen or Kelmesblume (Viola calaminaria) of Rhenish 
Prussia, and neighboring parts of Belgium, is there 
considered an almost infallible guide to calamine 
deposits, though in other districts it grows where no 
zinc ore has been found. In the zinc districts its 
flowers are colored yellow, and zinc has been ex- 
tracted from the plant. The same flower has been 
noticed at zinc mines in Utah. 

In looking for indications where superficial depos- 
its are known to occur, the prospector may be often 
guided, like the Tungusians in Northern Siberia, 
who search for gold by first looking at the general 
contour of the country, and observing those places 
where any obstacles, like a projecting range of hills, 

44 prospector's field-book and guide. 

would be likely to prevent material from being 
directly washed from higher to lower ground. 
Holes, sudden bends, or anything which would 
cause a diminution in the force of a current of 
water, are points at which it should be expected 
that heavy material like gold or platinum would be 
likely to collect. Although in Australia the most 
gold is generally found in pot holes and behind 
hard bars, it has often been found upon the shallow 
bends of ancient river courses. The lowest of a 
series of beds is generally the richest. In California 
the gold-bearing beds usually consist of gravels, 
which may be cemented to form a conglomerate, 
sands, bands of tuff, clay, fossil-wood, etc. 

Magnetite occurs in alluvial deposits. Bog iron 
and manganese ore which have accumulated by 
precipitation in marshy places or in lakes usually 
contain too much impurity to be of commercial 
value. Stream tin occurs in gravels in much the 
same way as gold. 

In examining a lode, the nature of the various 
minerals it contains and the proportions which 
these hold to each other should be observed. Some- 
times it will be noticed that certain groups of min- 
erals are often found together, the presence of one 
being favorable to the existence of the other. At 
other times the reverse will be remarked, the exist- 
ence of one mineral being the sign of the absence of 
another. The practical advantages to be derived 
from a series of observations indicating such results 
are too obvious to be overlooked. 



The following table, showing the association of 
ore in metalliferous veins, is given by Phillips and 
Von Cotta : 

Two Members. 

Galena, blende. 

Iron pyrites, chal 

Gold, quartz. 

Cobalt and nickel 

Tin ore, wolfram. 
Gold, tellurium. 

Cinnabar, tetrahe- 

Magnetite, cblorite. 

Three Members. 

Galena, blende, iron 
pyrites (silver ores). 

c Iron pyrites, chalcopy- 
■s rite, quartz (copper 
^ ores). 

Gold, quartz, iron py- 

Cobalt and nickel ores, 
and iron pyrites. 

Tin, ore, wolfram, 

Gold, tellurium, tetra- 
hedrite (various tel- 
lurium ores). 

Cinnabar, tetrahedrite, 
pyrites (various ores 
of quicksilver). 

Magnetite, cblorite, 

Four or More Members. 

Galena, blende, iron pyri- 
tes, quartz and spatbic 
iron, diallogite, brown 
spar, calc spar or beavy 

Iron pyrites, cbalcopyrite, 
galena, blende ; and 
spatbic iron, diallogite 
brown spar, calc spar; 
or beavy spar. 

Gold quartz, iron pyrites, 
galena blende ; and 
spatbic iron, diallogite ; 
brown spar, calc spar, 
or heavy spar. 

Cobalt and nickel ores, 
iron pyrites; and galena, 
blende, quartz, spathic 
iron ore, diallogite . 
brown spar; calc spar; 
or heavy spar. 

Tin ore, wolfram, quartz, 
mica, tourmaline, topaz, 

Gold, tellurium, tetrahe- 
drite, quartz, and brown 
spar ; or calc spar. 

Cinnabar, tellurium, tetra- 
hedrite, pyrites, quartz 
and spathic iron, diallo- 
gite, brown spar, calc 
spar ; or heavy spar. 

Magnetite, chlorite, gar- 
net, pyroxene, horn- 
blende, pyrites, etc. 



All chemical tests for minerals, whether with 
the blow-pipe or in the wet way, depend upon some 
chemical change which is brought about, thus 
allowing the element, base or acid, to be recognized. 
These changes consist either of the decomposition of 
the mineral, or the formation of fresh compounds. 
The following instances will sufficiently illustrate 
the character of these changes. 

If the oxide of a metal, copper for instance, is 
mixed with carbonate of soda and fused on char- 
coal, the copper is reduced to a metallic state, the 
oxygen combining with the charcoal to form car- 
bonic acid, which escapes as a gas, and any silica 
which is present decomposes the carbonate of soda 
to form a silicate of soda, which may be looked 
upon as a slag. 

If a hydrous mineral is heated in a glass tube 
closed at one end, the water is given off, and con- 
denses as drops in the cool part of the tube. 

If an arsenical mineral is heated in a closed tube 
a crystalline deposit of arsenic is formed in the 
tube ; but if it is heated in the air, white fumes of 
arsenious acid are evolved which smell like garlic. 



If a drop of hydrochloric acid be placed on a car- 
bonate, such as limestone, the presence of carbonic 
acid is recognized by the effervescence which takes 
place ; the stronger acid having combined with the 
lime has liberated the carbonic acid in a gaseous 
form. In the case of very many mineral car- 
bonates, the acid requires to be heated for this re- 

A great deal can be learned respecting a mineral 
by a few simple trials with the blow-pipe, and every 
prospector should learn to use it. The chief re- 
quirements are a plain brass blow-pipe about 7 to 10 
inches long, a candle, a forceps or pliers, some 
platinum wire, a small pestle and mortar made of 
agate, a small sieve, a magnet, some small glass 
tubes, and some good firm charcoal free from cracks 
and openings. 

The only reagents which will be absolutely neces- 
sary are borax, carbonate of soda and rarely micro- 
cosmic salt, nitrate of cobalt, and a little hydro- 
chloric and sulphuric acid. A few others are 
occasionally necessary, but their use is limited. 
The carbonate of soda should be perfectly dry, not 
merely dry to the touch but quite free from water. 
Such carbonate of soda may be prepared from com- 
mon washing soda by expelling the water it con- 
tains. Put the washing soda in a shallow, clean 
iron dish, and place it over a clear fire until a white 
dry power is formed ; avoid too strong a heat, 
otherwise the dry powder might fuse. A quarter of 
an ounce may be kept in a well-corked bottle or 

48 prospector's field-book and guide. 

tube for use. Bicarbonate of soda may be used in. 
stead without previous heating, or if the bicarbonate 
be moderately heated it loses weight, and becomes 
carbonate of soda, quite free from water, like the 

The borax is to be dried in the same way ; a 
quarter of an ounce will be enough. It is conven- 
ient to keep the platinum wire in the same tube. 
Unless these tubes are well corked, these chemicals 
reabsorb moisture. For testing tin ore it is useful 
to have a little cyanide of potassium kept in a bottle, 
with the cork and rim well covered with melted 
beeswax ; it would otherwise liquefy by absorption 
of moisture and become useless. It is a most dan- 
gerous poison, and the greatest caution must be ob- 
served in its use. 

The blow-pipe should have a fine jet, or aperture ? 
wide enough to admit of a fine needle. The mode 
of using it may be readily acquired by first breath- 
ing through the nostrils with the lips closed, then 
puffing out the cheeks (as if rinsing the mouth with 
water), still keeping the lips closed, and breathing 
as before. The blow-pipe may at this point be 
slipped between the lips, and it will be found that a 
current of air escapes through it without any effort 
on the part of the operator. Air flows through the 
pipe owing to the tendency of the distended cheeks 
to collapse ; it must never be forced from the lungs. 
After a little practice the strength of the current 
may be increased. By breathing entirely through 
the nostrils, keeping the lips closed, the blast may 


be kept up for ten minutes or longer without ex- 
haustion or inconvenience, except a slight fatigue 
of the lips in holding the blow-pipe. The beginner 
may practice blowing upon a piece of charcoal. 
The charcoal should, for convenience sake, be cut 
into slices of some six inches long by three-quarters 
to an inch wide and half inch thick. Place a piece 
of lead, or a pin-head, or fragment of pyrite (iron 
pyrites), near the end of the charcoal, and learn to 
blow the flame of a candle to a point upon the 
object. However awkward the blow-pipe may feel 
at first, practice will soon enable the learner to be 
expert. At first it may be necessary to gouge a 
small hole or recess in the coal with the point of 
your pen-knife, in order to prevent the specimen 
from being blown away. But after many trials 
such a command will be had over the blast that the 
hole may be made sufficiently deep by simply turn- 
ing the point of the flame upon the coal and burn- 
ing out a cavity. 

Study the two colors of a sperm candle flame 
(Fig. 11). Notice that there is a yellow flame out- 
side and nearer the top, and then within the flame 
there may be seen a bluish, probably a true blue 
flame. These flames act differently on the same 
substance. The outer F, or yellow flame, is 
called the " oxidizing flame," the inner, the " reducing 
flame," R F or I F. By blowing properly, these 
two flames may be made to turn horizontally, or 
even downward, and then either the flame or the 
R flame may be turned on the " assay " (as the ob- 



ject on the charcoal may be called). Get a piece of 
iron ore as large as a pin-head and place it in a 
little cavity on the charcoal, then cover it with a 
quantity of soda carbonate as large as the assay. 
Now turn the R flame down on the soda and ore, 
and in a few seconds the ore will melt and be re- 
duced to metallic iron, and your magnetized knife- 

FlG. 11. 

A, the blue or reducing flame ; B, the oxidizing flame ; C, the end of the 

By placing the end of the blow-pipe in the flame thus, the oxidizing flame, 
A, is made more efficient. 

blade will pick it and the soda up. In this experi- 
ment a piece of red or brown hematite, or a piece of 
pyrite (iron pyrites), should be used, as neither will 
be attracted by the knife-blade before the ore is re- 
duced to metallic iron. The reason for this action 
on the part of the ore is that the ore is metallic iron 
combined with oxygen, and the R or blue flame calls 


for more oxygen than it possesses, so that when it is 
turned upon the hot oxide of iron it takes the 
oxygen it calls for, from the ore and leaves the iron 
in a metallic state. But in the pyrite, which is iron 
and sulphur, the latter is partially driven off by 
either flame ; and this process, on a larger scale, is 
called "roasting." The soda absorbs a part of the 
sulphur and part remains in the iron, but not so 
much but that the magnetized knife-blade will at- 
tract it. The last experiment is good for experi- 
mental practice, but not for illustrating the two 
properties of the flame. 

The following is an excellent illustration and 
practice in showing the characteristic power of either 

Fig. 12. 
1 / //// ////// i ^ 

Appearance and size of wire and loop, A. 

flame. Get some platinum wire of the size of a 
large horse-hair. Wrap it around a match, leaving 
an end extending an inch and a half beyond the 
match end, then roll the end of the wire around 
another match until you have bent the end of the 
wire into a small loop (Fig. 12). Prepare a little 
powder of common borax, and then, heating the 
wire loop in the general flame, plunge it quickly 
into the powdered borax. It will immediately pick 
up a quantity of the powder, and then, by turning 
the flame upon the borax, you will have a clear and 


perfectly transparent bead filling the little loop on 
the end of the wire. You are now ready for the 
experiment of illustrating the special properties of 
the two flames, which we shall now describe. 

Obtain some black oxide of manganese, from any 
druggist, and dropping a little upon a clean sheet 
of letter paper, heat your borax bead red-hot in the 
flame and quickly touch with the hot bead a parti- 
cle of the black oxide — it will stick to the bead — 
then turn the outer or flame upon the bead and 
blow till the particle of oxide of manganese has en- 
tirely dissolved — it will impart to the bead a beauti- 
ful amethystine-purple. Now turn the inner flame, 
that is, the R flame, upon the bead, and in a few 
seconds (according to skill in keeping the R flame 
steadily on the bead) the color will disappear, but it 
will return when the flame is used again. 

These efforts will give practice, ending in suffi- 
cient skill to enable the learner to use the blow-pipe 
as directed in the future parts of this work. 

The various reactions of different substances are 
given in the body of this book as they are called for 
when the substances are described. 

A glass tube of a little less than three-eighths of an 
inch in diameter may be made into a blow-pipe as 
follows : Take a piece of such a tube, ten or twelve 
inches long, soften the tube by red heat in an alco- 
hol flame, and draw it out to a small diameter — 
cool and scratch or file it at the smallest diameter 
— -break it off, introduce the tube into the flame 
again and bend the glass to a right angle, about 


two inches off from the point — cool gradually — and 
heat the mouth end, opening it a little by introduc- 
ing a small dry pine stick, cool it, and you have a 
very efficient blow-pipe when another of metal can- 
not be had. 

Note: If your platinum loop will not hold the 
borax bead, then it is too large. Make a smaller 
loop. If it is dimmed or blackened by smoke, heat 
it red-hot — it will clear up. 

The three principal means of chemically testing 
minerals before the blow-pipe are (1) with borax ; 
(2) on charcoal, usually with the addition of car- 
bonate of soda ; (3) by holding in the oxidizing 

In connection with this the following experiments 
given by Alexander M. Thomson, D. Sc., are of in- 
terest : 

Experiment No. 1. — Many metals impart a color 
to fused borax, by which their presence can be 
recognized. To try this experiment, a bead of 
fused borax must first be obtained on the platinum 
wire. The end of the wire is bent into a loop or 
ring about the twelfth part of an inch in diameter. 
The wire is then heated in the blow-pipe flame, and 
dipped whilst hot into the borax ; the portion of 
borax that adheres is then fused on to the wire in 
the blow-pipe flame, and the hot wire is again 
dipped ; this is repeated until the loop contains a 
glass-like bead of borax. If the bead has become 
cloudy, the soot causing this may be burnt off in 
the oxidizing point of the flame. Having thus ob- 


tained a clear, colorless, transparent bead, the next 
step is to add to it a minute portion of the mineral 
which is to be tested. By touching a little of the 
finely pulverized mineral with the borax bead, while 
softened by heat, enough will adhere to the bead for 
a first trial. The bead is then kept at a white heat 
in the oxidizing point of the flame for a few seconds, 
and on removal its color is noted, both whilst hot 
and when cold. If no color is imparted, a fresh 
trial may be made with a larger quantity of the 
powder ; but if the bead is opaque owing to the 
depth of color, as is often the case, a fresh experi- 
ment must be made, using a still smaller quantity 
of the powder. The color can only fairly be judged 
in a perfectly transparent bead. If no color can be 
obtained in the oxidizing point, further experiment 
with the borax bead is needless ; but if a color is 
obtained, it is then advisable to try the effect of the 
reducing flame upon the same bead. The following 
observations and inferences may result from this test : 


Oxidizing Reducing Presence of 

Green (hot); blue (cold) . . . Ked Copper. 

Blue (hot and cold) Blue Cobalt. 

Amethyst Colorless Manganese. 

Green Green Chromium. 

Ked or yellow (hot) . . . . -» 

Yellow or colorless (cold).. } bottle-green Iron. 

Violet (hot) ; Red-brown 

(cold) Gray and turbid, diffi- 
cult to obtain . . . Nickel. 

This mode of testing may often be used to prove 
the presence of the above-mentioned metals. 


It requires some practice before reliable results 
can be obtained in reducing. The reduced bead, if 
brought out of the flame at a white heat, into the 
air, may at once oxidize ; but this may be prevented 
by placing it inside the dark inner cone of an ordi- 
nary candle flame, and allowing it to cool partially 

Experiment No. 2. — The mode of testing with car- 
bonate of .soda on charcoal, is performed as follows : 
A sound piece of charcoal half an inch square is 
chosen, and a neat cavity is scooped out on its 
surface, into which is placed a mixture containing 
the pulverized mineral to be tested, with three or 
four parts of carbonate of soda, the whole not ex- 
ceeding the bulk of a pea. After lightly pressing 
the mixture into the cavity, the blow-pipe flame 
may be cautiously applied to it ; and afterwards 
when the mixture no longer shows a tendency to 
fly off, the charcoal may be advanced nearer to the 
blow-pipe, and finally be kept at as high a tempera- 
ture as possible, in the reducing part of the flame. 

In testing for tin ore, a piece of cyanide of potas- 
sium, about the size of a pea, may be placed upon 
the mixture after the first application of heat, and 
the further application of heat may then be con- 

This treatment is designed to extract metals from 
minerals; it favors in the highest degree the re- 
moval of oxygen. But like the borax test, it is 
limited in its application, as it can only be used to 
detect certain metals. The failure of the test in any 

56 prospector's field-book and guide. 

case must not be looked upon as a conclusive proof 
of the absence of the particular metal sought ; for 
instance, copper can be easily extracted from car- 
bonate of copper by this test, but not from copper 
pyrites. Still the test is a most valuable and indis- 
pensable one to the mineralogist. The test is com- 
plete when the metal is obtained as a globule, in 
the cavity of the charcoal. In many cases the 
globule will be found surrounded by the oxide of 
the metal, forming an incrustation on the charcoal ; 
and the color of such incrustation should be carefully 
noted, both at the moment of removal from the 
flame, and after cooling. By pressing the globule 
between smooth and hard surfaces, it can be deter- 
mined whether the metal is flattened out (or malle- 
able), or crushed to pieces (brittle). 

The following observations and inferences may 
result from this test : 

Globule Incrustation Presence of 

Yellow, malleable .. None Gold. 

White, malleable . . None Silver. 

Eed, malleable . . . None Copper. 

White, malleable . . White Tin. 

White, malleable . . Red (hot); Yellow (cold) . . . Lead. 

White, brittle .... Red (hot); Yellow (cold) . . . Bismuth. 

None Yellow (hot) ; White (cold) . . Zinc. 

White, brittle, giving 
off fumes when re- 
moved the the flame. White Antimony. 

Experiment No. 3. — In addition to these substances 
there are others which occur abundantly in minerals, 
and which may be recognized by the blow-pipe with 


the greatest ease ; for instance, sulphur and arsenic. 
These may be discovered by heating a fragment of 
the mineral, supported on a piece of charcoal or 
held in a forceps in the oxidizing point of the 
flame, and comparing the odor which is given off. 
A smell of burning sulphur indicates that the min- 
eral contains that substance, and white fumes hav- 
ing a garlic odor indicate the presence of arsenic. 

Mercury, antimony, and other substances may 
escape as fumes when heated in this manner. 

Nitrate of cobalt dissolved in water, and used in 
exceedingly small quantity, helps to discriminate 
between certain white minerals, such as kaolin, 
meerschaum, magnesite, dolomite, etc. The mineral 
is reduced to powder and moistened with a drop of a 
very light solution, and then heated before the oxid- 
izing flame of the blow-pipe. Kaolin and other min- 
erals containing alumina assume a rich blue color, 
while meerschaum and other minerals containing 
magnesia become flesh-colored. Oxide of zinc, 
under the same circumstances, becomes green, and 
this can be tried with the white coating obtained 
on charcoal by reducing an ore of zinc with car- 
bonate of soda. 

Tests in glass tubes can be better made over a 
spirit lamp, so as to avoid the deposit of soot on the 
glass, but they can also be made with the blow-pipe 
flame, provided it is used carefully, avoiding too 
sudden a heat, which would break or fuse the glass. 
The presence of water in minerals will be detected 
in this way, and the water collects in small drops in 

the cold part of the tube. Some minerals contain- 
ing sulphur, arsenic, antimony, tellurium and selen- 
ium often give a characteristic deposit. 

Minerals containing mercury can also be tested 
in this way, as by adding a little carbonate of soda, 
sometimes with cyanide of potassium, a sublimate 
of metallic mercury will be formed in the cold part 
of the tube. A little charcoal should be added to 
arsenical minerals. 

Organic combustible minerals generally leave a 
deposit of carbonaceous matter at the bottom of the 
tube, and the volatile hydrocarbons condense in the 
cooler part. The tube should, therefore, always be 
long enough to allow for this condensation.. Min- 
erals which yield a characteristic smell will be best 
tested in this way. 



The forms which many minerals assume always 
indicate their composition. It is, therefore, some- 
times a great help to the prospector to become ac- 
quainted with the subject of crystallography so far 
as to enable him to determine the system or order 
to which a crystal belongs. 

We shall treat of the subject only so far as may 
be of practical application to the purposes of the 
prospector in the search for the useful minerals. 

It is necessary to understand that nearly all 
mineral substances, when they appear in the crys- 
talline condition, assume a characteristic form and 
do not trespass upon that of other minerals. Al- 
though, to the unaided eye and unskilled vision, 
this assertion may appear to be a mistake in some 
few cases, it appears so only because the differences 
are exceedingly small. 

All crystalline forms have been reduced to six 
classes or systems, which are named as follows : I. 
Isometric; II. Tetragonal; III. Hexagonal; IV. Or- 
thorhombic; V. Monoclinic ; VI. Triclinic. 

I. Isometric system. The principal forms of this 
system are the cube, octahedron, dodecahedron, the 


two trisoctahedrons, the tetrahexahedron, and the 

The cube has six equal and square sides, as in 
Fig. 13. In this form lines drawn from the centre 
of each face to the face opposite, cross each other at 
right angles, and are of the same length. 

This system is called isometric, that is, iso equal, 
and metric measure, because these axes or lines are 
of equal length and at right angles to each other. 
It must, however, be remembered that the cube is 
modified in some minerals, but wherever these modi- 
fications take place the original form of the cube 
may always be traced. Some of the changes may 
be very intricate, and these especially unusual or in- 
tricate forms we shall not notice. The usual forms 
only are of importance, and can be treated of in so 
small a work as this. 

The learner should take a potato and cut as per- 
fect a cube as possible, and make himself acquainted 
with the common variations which may belong to 
the cube, as we shall show, with- 
out changing the length of the 
axis, and always, cutting so that 
the axis will always be the same 
or of equal lengths. 

Fig. 13 is the cube with the 

three axes A A', B B' , C C. If, 

with your knife, you slice off one 

edge angle from A to C and from A to C, and in 

like manner from A to B' and from A to B, you will 

have a four-sided pyramid, the apex of which will 



be at A and the four-sided base at C B f , C B, or 
around one-half the cube. Now, treat the opposite 
side in the same way, and you will then have the 
following figure, which is the octahedron (Fig. 14). 
The dodecahedron (12 sides), Fig. 15, may be 
formed by taking off the solid angles A, B, B', A' '. 
In all three cases and many others, the three axes 
remain the same in length and in their angular 
direction where the forms have not been distorted. 

Fig. 15. 


The Octahedron. 

The Dodecahedron. 

II. Tetragonal system. The chief forms of this 
system are the two square prisms and pyramids, 
and the eight-sided prism and double eight-sided 

The tetragonal system has also three axes as in 
the isometric, and they are at right angles to each 
other, but the vertical axis is longer than the others, 
as in Fig. 16. 

The term tetragonal means " four-cornered or an- 
gled," and is not precise, for a cube is tetragonal, 
but it is used to express this form because it is one 
word ; otherwise " square prismatic " would be a 
more correct description, since Fig. 16 is that of a 



prism ; for in mineralogy any crystal having paral- 
lelograms for sides is called a prism. Cut this 
prism as in the case of the cube, and you will have 
the form seen in Fig. 17. 

Variations upon this form may show a prism with 
four-sided termination at either or both ends, as in 
Fig. 18. This is the form of the transparent gem 
called the zircon, anciently called the jacinth. The 
zircon has been mistaken for the diamond, which it 
resembles in brilliancy, and somewhat in hardness. 
But the diamond is isometric and never tetragonal, 

Fig. 16. 

Fig. 17. 

Fig. 18. 


Tetragonal Prism. Tetragonal Octahedron. The Zircon. 

and hence it may be distinguished readily from the 

III. Hexagonal system. The chief forms of this 
system are the two six-sided prisms, the two double 
six-sided pyramids, and the twelve-sided prism and 
double twelve-sided pyramid. It differs from the 
tetragonal system in that it has three equal lateral 
axes instead of two ; the vertical being at right' 
angles, as in Fig. 19, with each of the three lateral. 



But it must be remembered that owing to various 
causes in nature the hexagonal crystal always calls 
for hexagonal terminations ; thus Figs. 20 and 21. 

Owing to various causes in nature, the hexagonal 
crystal may be found under various modifications 
of the hexagonal form, but it can always be reduced 
to this system. The symmetry of the crystals may 
be by sixes, or very rarely, by cutting each angle 
it may be in twelves, or the sides may be unequal 
in area or length, as in Fig. 20. The author once 
found a quartz crystal in Switzerland which was, for 

Fig. 19. 

Fig. 20. 

Fig. 21. 


Hexagonal Prism. 

Quartz-Crystals— Hexagonal. 

nearly its entire length, three-sided, but showed its 
hexagonal nature only at the extremity, where, hav- 
ing been free from its confinement in process of for- 
mation, it had assumed its normal crystallization. 
As has been said in another place, calcite crystals 
sometimes assume a hexagonal prism precisely as 
does quartz, but the latter shows always six-sided 
terminations, whereas lime or calcite crystals show 
three-sided terminations, as in Figs. 22 and 23. 
There are two sections or forms of this system, the 
hexagonal and the rhombohedral ; both belonging to 



the hexagonal system, and distinguished as we have 

These calcite crystals belong to the rhombohedral 
section of the hexagonal system, showing rhombo- 
hedral forms at the end, as in Fig. 17. 

Fig. 22. 


Fig. 23. 

Calotte hexagonal crystal— three-sided 
termination. Side view. 

The same— end view. 

IV. Orthorhombic system. The characteristic 
forms of this system are the rhombic prism and 
pyramid. There are also other forms called domes. 





i | 

! '■■■.. 


1 • 

i t 

i" -,,J 


In this system the three axes are unequal and in- 
tersect at right angles, as in Fig. 24, wherein the 
axes, A, B, C, are unequal in length, but at right 


angles at the intersection. The terminations are 
flat although frequently beveled on the surrounding 

V. Monoclinic system. The monoclinic forms 
are too difficult to be fully described here, but it is 
not hard to learn what is most essential about them. 
In this system two of the axial intersections are at 
right angles ; but one is oblique, and the side of 
the crystal is inclined as in Fig. 25. 

Crystals of feldspar in general which contain pot- 
ash (called orthoclase or potash feldspar), are mono- 
clinic, but the soda feldspar crystals belong to the 
next or sixth system, as do also the lime feldspars. 

VI. Triclinic or " thrice inclined " system. In 
this system the planes are referred to three unequal 
axes all oblique to each other. The only import- 
ant feature in this system is that there is no right 
angle in any of its crystals ; but it is of little use for 
our purposes, since with the exception of the lime 
feldspar and soda-lime feldspars (anorthite or lime 
feldspar, labradorite or soda-lime feldspars, andesitej 
and oligoclase, both soda-lime feldspars, and albite, 
a soda feldspar \ all the rest are of little importance,, 
except microcline, a, potash feldspar:. 

As- illustrations 03 these systems the follow- 
ing may be stated : : 

Of the isometric system, or first system, are gold, 
silver, platinum, amalgam, copper, the diamond, 
garnet, magnetite, pyrite> galena, alum, kalinite, all 
of which assume the cubic octahedral, or some allied, 


Of the tetragonal, or second system, are the zir- 
con, chalcopyrite, cassiterite (tin ore), titanic oxide, 
and others. 

Of the hexagonal, or third system, are beryl, 
aquamarine, the emerald, chrysoberyl, apatite (lime- 
phosphate), quartz. 

Of the orthorhombic, or fourth system, are 
barite or sulphate of barytes, celestite or sulphate 
of strontia, and carbonate of strontia, also cerussite 
or lead carbonate. 

Of the monoclinic, or fifth system, are borax, 
gypsum, glauber salt (mirabilite is its mineralogical 
name), copperas (or melanterite). 

Of the sixth system we have already given suffi- 
cient illustrations. 

Of the gems not mentioned in the above, the tur- 
quois owes its blue to copper, and is never crystal- 
lized, being in reniform or stalactitic conditions. It 
is a phosphate of alumina with water in composi- 
tion. This mineral or gem should be carefully 
distinguished from lazulite, which, though blue, 
crystallizes in the monoclinic, or fifth system ; it is a 
softer mineral and contains considerable magnesia, 
lime, and iron, of which (except a very small 
amount of iron), the true turquois contains none. 
The latter is the gem, and may be beautifully pol- 
ished, and keeps its color, which is due to copper. 
Lazulite is found in beautiful crystals at Crowder's 
Mount, in Lincoln Co., N. C; also fifty miles north 
of Augusta, at Graves's Mount, in Lincoln Co., 


Both these should also be distinguished from 
lapis lazuli, which also crystallizes, but in the 
isometric or first system, though commonly massive 
and compact. This is valuable in the arts, and 
when powdered forms the ultramarine, sl rich and 
durable paint. It is a silicate of alumina, but con- 
tains some lime and iron. It is used also for costly 
vases. But the artifically prepared ultramarine is 
largely used in the arts. The native mineral is 
found in syenite and in metamorphic crystalline 
limestone, associated with pyrite and mica. 

The topaz crystallizes in the orthorhombic sec- 
tion of the hexagonal or fourth system. The finest 
are generally in prismatic form, showing a flat plane 
at the extreme end, even when the end of the 
crystal has several inclined faces. It is a silicate of 
alumina with fluorine. The fluorine may be de- 
tected before the blow-pipe in the open tube by 
powdering a little of the topaz and mixing it with a 
little microcosmic salt (a salt of phosphorus). The 
heat of the blow-pipe will let free the fluorine, and 
its strong pungent smell, and its corrosion of the 
tube, will prove its presence. With the cobalt 
(nitrate) solution on charcoal, it gives a fine blue 
color in proof of alumina. This is the best test of 
the topaz, as the color of the mineral is not always 
the same, nor is it always perfectly transparent. It 
is found at Crowder's Mount, already spoken of, and 
also in Thomas's Mountains, in Utah, near lat. 39° 
40' and long. 113|° W. west of south of Salt Lake 
(Dana). In Trumbull, Conn., the crystals are 
abundant, but not very transparent. 

68 prospector's field-book and guide. 

Meteoric Iron has been reported from North 
Carolina as found native in a partial crystal of the 
isometric form, and several meteoric masses from 
Arizona have been reported at the Geological Section 
at Washington, D. C, September, 1891, as contain- 
ing black diamonds, small but interesting. 

Meteorites are less pure than native iron, the iron 
in them being almost invariably associated with 
nickel, and they also contain traces of cobalt, cop- 
per and other metals. In the many specimens ex- 
amined, the iron ranges from 67 to 94 per cent., 
and the nickel from 6 to 24. Their masses gener- 
ally range from a few pounds in weight to a ton or 
more. If cut, and the surface is polished, and then 
acted upon by nitric acid, a kind of etching action 
goes on, the acid acting on spaces between bands of 
untouched metal which cross the mass in two or 
three directions, and in these the nickel is more 
abundant than in other parts, for it is not equally 
diffused in the alloy. 

Ruby and Sapphire. These crystallize in the 
rhombohedral form. 

The garnet is sometimes mistaken for the East 
Indian ruby, which is the most precious variety, 
but the garnet is isometric, and even when cut and 
mounted may be distinguished from the oriental 
ruby by the superior hardness of the ruby, the latter 
being next to the diamond, while the garnet is only 
as hard as quartz, or not quite so hard. So that a 
garnet of the most precious kind if worn will, under 
the strong lens, show the lines of wear, especially on 


the edges, which are absent in the true oriental 
ruby. Oriental garnets are frequently confounded 
with rubies by jewelers in Paris as well as in 
America. For instance, some years ago, two oriental 
garnets worth about $20 each were found to be set 
in a diamond ring as oriental rubies, for which the 
sum of $2,000 was paid. The firm in Paris ac- 
knowledged the mistake, and refunded the $2,000. 
The oriental ruby is essentially pure alumina, while 
the oriental or precious garnet is a silicate of alum- 
ina with lime and a little iron. 

All these gems are found in the crystalline rocks, 
as granites, gneiss, dolomite, and some (topaz, ruby) 
associated with tourmaline, tin ores, mica, etc., and 
the crystalline lime-stones. The true turquois is 
found in Persia in the clay slates in veins running 
in every direction. Very good specimens have been 
found in Arizona and New Mexico ; also in Colo- 
rado in the Holy Cross Mining district, thirty miles 
from Leadville. 



There are a few simple measurements which are 
sometimes desirable, and which can be made with- 
out the labor of carrying instruments and chains. 
The actual work of surveying, to be of any value to 
the prospector, must be so accurately performed that 
the work should be entered upon as a specialty, and 
he must use a theodolite or transit and make use of 
logarithms. Any small work on surveying or 
trigonometry will give sufficient information.* 

Some few measurements, however, and simple 
surveys with easy methods, are given here to meet 
cases where only a general approximation is re- 


Any height of tower, stand-pipe, tree, etc., may be 
measured approximately by knowing your own 
height and taking advantage of sunlight, thus : 

Let A B, Fig. 26, be the height of the object to 

*For this purpose we would recommend the following 
book: The Practical Surveyor's Guide. By Andrew Duncan. 
A new, revised and greatly enlarged edition. Illustrated 
by 72 engravings. Philadelphia, Henry Carey Baird & Co., 
1899. Price, $1.50. 



be measured. The dotted line is the shadow cast. 
Walk off into the sunlight and note on the ground 
the point at which your own shadow terminates ; 
measure from the heel to that point. A calculation 
in single " rule of three " will give A B thus : 

C" B' : B' A' : : B C : A B. 

Heights of hills or land may be nearly enough 
measured by the aneroid barometer, the instructions 
in the use of which go with the instrument, or may 
be obtained with it, and approximately accurate 
aneroids may be had small enough to go into the 
side pocket, or still more accurate ones may be 
easily carried in a case held by a small strap around 
the shoulders. For hills under 2000 feet, the fol- 

Fig. 26. 

~ jar 


lowing rule will give a very close approximation, 
and is easily remembered, because 55°, the assumed 
temperature, agrees with 55°, the significant figures 
in the 55,000 factor, while the fractional correction 
contains two fours. 

Observe the altitudes and also the temperatures 
on the Fahrenheit thermometer, at top and bottom 

72 prospector's field-book and guide. 

respectively of the hill, and take the mean between 
them. Let B represent the mean altitude and b the 


mean temperature. Then 5500 x = height 

B -h b 

of the hill in feet for the temperature of 55°. Add 
^\q of this result for every degree the mean temper- 
ature exceeds 55°; or subtract as much for every 
degree below 55°. 

to measure areas. 

Theoretically, it is very easy to " step off lines/' 
but practically it is very difficult thus to arrive at 
accuracy on uneven land. But where one is ac- 
quainted w T ith the exact average measurement of 
his step on level land, he may reach some approxi- 
mate accuracy on uneven land by remembering 
that in ascending, even slightly, his average de- 
creases, and vice versa in descending. A good strong 
tape measure, kept on a level in ascending and de- 
scending hills, is more convenient and more easily 
handled than a chain. 

1. On square areas the length of the side multi- 
plied into that of the adjacent side gives the area. 

2. In the parallelogram, where all angles are 
right angles, the same is true. 

3. In any other shapes the following rules are to 
be observed : 

First : Measure the area of a right-angled tri- 
angle thus : 




Let B, Fig. 27, be the right-angle ; the aafca of 
J. .6 (7 is equal to the length, 
B C, multiplied into half 
the perpendicular distance, 

Example: # € = l$)fe; 
•therefore, if 4 J5--='SK) oft,, 
100 x 45 = 4500 sq. ft. = 
area of A B C. 

The same rule applies 
when the triangle is not a 

right-angled triangle; thus, the angle at A, Fig. 28, 
being obtuse. 

D C= 150 ft., A B = 90 ft.; multiply 150 ft. by 

Fig. 28. 

one-half A B = 45 ft., and we have 6750 sq. ft., for 
i CD is composed of two right-angled triangles, 
A C B and A B D, as in the previous example. 

Or, when the triangle has an acute angle at A, 
Fig. 29, thus : Treat precisely as in Fig. 28, only 
letting the perpendicular fall from D upon A C, 
that is, invert the triangle. 

The cases wherein the sides are more than three 



are treated by resolving all such areas into right- 
angled triangles, thus : 

In Fig. 30, the area, A C D B may be resolved 
into two triangles, A C B and C D B, of which A B 

Fig. 29. 

is the base of the one and C B that of the other. 
In Fig. 31, the area, A C D B E K, may be re- 
solved into the four triangles, AC D, A D B, ABE 
and' A E K. The perpendiculars of Fig. 30 are 

ED and C F. Those of Fig. 31 are C H, IB, 
F E, and K G, and the length of bases may be 
multiplied into half that of the perpendiculars, as 
in the case already given, and the feet be reduced 
to acres, rods, etc., or miles. 



For the number of square feet in an acre, etc., 
see Appendix No. 3, and treat it thus : Suppose the 
area of Fig. 31 be 80,000 sq. ft., then according to 

Table No. 3, it will be 1 acre, 3 roods, 13 poles, 25 
yards, 7 feet, or 1.836 + acre. 


Suppose we desire to measure the distance across 
a river, as in Fig. 32. 

We want to find the distance A B. Measure a 
distance of about 100 ft., B D, at right angles to 
A B, and raise a pole at 0, about half-way from B 
to D. Proceed in measuring at right angles to B D, 
in the direction D E, letting E be that point at 
which the line C E, if extended, would strike A. 
Now you have two right-angled triangles of the 
same angles, for, as every triangle has two right- 

76 prospector's FlELD-BOOK and guide. 

angles according to geometry, and each of these tri- 
angles has one right angle, and the opposite angles 
at C are equal according to geometry, the remaining 

Fig. 32. 



angles at A and E are equal, and the triangles are 
proportional, and the proportion is — 

C D : D E : : C B : A B. 

Then, if C D = 40 ft., D E = 45 ft., and C B = 60, 
we know that 45 x 60 = 2700 divided by (C D) 40 
ft. = 67 J ft.; this is for A B, or the distance across 
the river. 

The only difficulty is in measuring your angles 
as true right angles, and this may be done by 
measuring the perpendicular, thus — 

Extend the line A B, Fig. 32, to F, Fig. 33, and 
likewise the line D E, Fig. 32, to C, as in Fig. 33. 
Now measure equal distances on the line B D, for 
the lines or offsets, B C and B H; also from D C, 



the offsets D I and D K ; drive sticks in at G, H, I, 
and K. See that the distances represented by the 
dotted lines are equal, and if so, the lines A B F 
and D C are perpendicular to the line G K, and 

Fig. 33. 





your work will be well done and very nearly ac- 

It is, however, well for the prospector to use a 
prism compass which will read to one-quarter de- 
gree. Such a compass may be had at very low 
rate, not more than three inches diameter, of light 
weight and of sufficient accuracy. The author has 
used one for many years, and traveled with it many 
thousands of miles in Asia and Africa, and can 
testify to the fact that by customary use it may be 
handled to a great degree of accuracy for horizontal 
angles. The needle is attached to the under side 
of a cord with steel engraved degrees and fractions, 
and read by a magnifying prism. 

In almost every conceivable surveying project, 
especially in running adits and sinking shafts to 

78 pkospector's field-book and guide. 

strike adits and galleries, only the best instruments 
should be used. Everything depends upon the 
most accurate measurements, and this department 
of engineering is not one that can be treated ap- 
proximately, because any error in measurement 
may result in very provoking and expensive mis- 

We have presented all that is required on surface 
measurements, except where it becomes necessary 
to make such accurate proceedings as may only be 
executed by use of the finest instruments, and that 
with considerable practice. Otherwise accurate 
mathematical tables are of little importance, as 
their use is based upon the presence of most ac- 
curate data, and without this the best methods and 
diagrams are in vain. 

This subject of mining engineering does not come 
within the range of our work, and for all mere ex- 
ploring as a prospector such ground-work or digging 
for examination as is necessary will readily suggest 
itself to any intelligent workman. 



I. Wet Method. 

Preliminary examinations may be made at 
first with the pocket lens and a piece of steel or a 
heavy-bladed pocket-knife. The first, to see if any 
native metals or any sulphides, etc., are present ; 
the second, to try the softness or silicious nature 
of the mineral ; if much quartz (silex) is present it 
will strike fire. 

Pulverize a small part and use the blow-pipe to 
detect sulphur, arsenic, selenium, by the smell 
on charcoal or in the glass tube. Arsenic fumes 
have a garlic odor, silenium that of horse-radish. 

Use a test-tube with a little nitric acid and heat 
over a spirit flame. Add a few drops of water and 
one drop of sulphocyanide of potash — an intense 
deep red appears, deeper according to amount of 
iron and solvency of the mineral in nitric acid. 

Try another portion in the same way, but drop 
one drop of hydrochloric acid. A dense curdy 
white precipitate indicates silver. 

Native gold or silver is determined by color and 
softness, as we have elsewhere stated (see Index). 
Treat another portion in the same way with nitric 


80 prospector's field-book and guide. 

acid, drop in several drops of strong ammonia 
water. The blue color indicates copper. 

Antimony and tin are detected by the blow-pipe. 
Place the former upon charcoal with carbonate of 
soda, and brilliant metallic globules are obtained ; 
the metal fumes and volatilizes, and covers the 
charcoal with white incrustations, and needle- 
shaped crystals appear. Tin appears when the ore 
is mixed with carbonate of soda and cyanide of 
potassium on charcoal, and the inner flame turned 
on — ductile grains of metallic tin and no incrusta- 
tions appear. 

Manganese gives amethystine beads of borax in 
the outer flame, F, disappears with the inner, 
I F, reappears with the F. 

Alumina, magnesia, lime, give their characteristic 
colors, or in the last case, incandescent light before 
the blow-pipe on charcoal. Alumina heated on 
charcoal, and then touched by a half drop of proto- 
nitrate of cobalt, then heated strongly in the 
flame, gives a blue color. Magnesia so treated gives 
a faint red or pink, seen just as it cools. 

Zinc heated on charcoal with carbonate of soda 
in the reducing flame becomes metallic, and when 
oxidizing in the flame gives a white oxide which 
is yellow when hot, white when cooled, and with 
protonitrate of cobalt when heated in the flame, & 
beautiful characteristic green color. 

Cobalt and nickel give the colors we have noticed 
in another place under their respective names (set, 


Uranium heated with microcosmic salt (phosphate 
of soda and ammonia), on platinum wire in the 
flame dissolves, producing a clear yellow glass, 
which, on cooling, becomes yellowish-green. But 
the analyst should remember that copper also pro- 
duces a green bead, but only in the outer or oxidiz- 
ing flame, and chromium the same, but in both 
outer and inner flames. 

The copper green becomes blue on cooling, the 
chromium green remains green on cooling. This 
will always prove the metal. 

Titanium in the presence of peroxide of iron, as 
in some titanic ores of iron and sand, gives, with 
microcosmic salt in a strong reducing blow-pipe 
flame, a yellow glass, which on cooling becomes red. 

Mercury may be detected in almost any of its ores 
by the process described {see Index), by heating in a 
glass tube and noting, under the lens, the sublima- 
tion of mercury in very minute shining particles. 

Minerals which are carbonates may be detected by 
their effervescence when touched by a drop of hydro- 
chloric acid, as in limestone and spathic iron ore. 
But the analyst must remember that some cyanides 
effervesce where neither lime nor carbonic acid is 
present, and chloride of lime where there is no car- 
bonic acid. With these latter other tests must be 
used, but the sense of smell will show that, carbonic 
acid does not exist, the latter having no odor. 

Some sandstones have a small amount of lime 
carbonate and must be tried under the lens, as the 
bubbles are minute. But, while in these examina- 


tions great help is received, and many determina- 
tions made, especially in simple minerals and ores, 
there are compound ores so mixed in elements that 
the above tests fail to give satisfaction, because the 
colors are mixed and the action confused. Some 
of the elements must be moved out of the associa- 
tion and a separation made. This analysis is called 
qualitative, and we shall take a case of very full 
analysis of a compound ore. 

Qualitative analysis of ores where many ele- 
ments are present : 

There are many times when it becomes not only 
a matter of curiosity but of importance for the 
prospector to know the entire composition of the 
ore he has before him. 

With a little practice the " wet method," as it is 
called, may be used by the prospector with all the 
accuracy required under the circumstances. 

The " dry method " of analysis is that in which 
no liquids are used, but only fluxes and heat. 
Although for one or two elements it is simpler than 
the wet method, it may so happen that sufficient 
heat cannot be had. We shall, therefore, give 
some directions whereby the wet method may prove 
of greater service. 

1. Pulverize the ore as finely as possible and 
sieve it, passing the entire quantity taken as an 
assay. Should any part be left remaining in the 
sieve it may be a very important part. Pass the 
whole through. 

2. Take a test tube and drop a little of the sifted 


ore into it, pour a little nitric acid upon it, add 
about one-eighth part water, warm it gently over a 
spirit flame to see if it will dissolve; if not, then add 
four times as much in bulk of muriatic acid (hydro- 
chloric acid). If this will not dissolve then proceed 
as follows : 

3. Put the assay, after fine pulverization, into a 
platinum crucible. Place it in a suitably arranged 
platinum wire triangle so that it will hang over an 
alcoholic blast lamp. When all is ready add a 
mixture of equal parts of sodium carbonate and of 
potassium carbonate, amounting in all to about four 
times the bulk of the assay, stir gently with a glass 
rod or a stiff platinum wire, and then light the 
lamp. Watch the assay, and when it begins to 
swell up withdraw the lamp, but return it when the 
swelling subsides, so that the alkalies do not throw 
your assay out of the crucible, which should be only 
one-half full at the beginning. With care the con- 
tents will soon subside, and under increased heat 
become a quiet liquid mass. Now, extinguish the 
flame, cool the crucible, remove crucible contents to 
a beaker glass or place the crucible with its con- 
tents within the beaker, and pour a little water 
upon it, add some nitric acid, or a little hydrochloric 
acid, but not the two acids together, unless you have 
only the assay and not the platinum crucible in 
the beaker — nitro-muriatic acid dissolves platinum. 
Warm and stir till the assay is entirely dissolved, 
except perhaps some white grains of silex. 

4. If the preceding work has been properly per- 


formed, the assay is now dissolved and you are 
ready for work. Filter the contents of the beaker 
to separate any undissolved remainder, if any such 
is seen in the glass, and wash the filter-paper by 
passing an ounce or two of water through it, and 
now make preparations for the next step. It is not 
necessary, where extreme accuracy is not required, 
to wash the filter-paper perfectly free from the acids. 
But if it be necessary, then furnish yourself with a 
small strip of platinum ribbon ; clean its surface to 
a polish. If a drop of the filtrate evaporated from 
this surface shows not the least trace of sediment or 
outline even under a lens, the filter-paper is suffi- 
ciently washed. When the filter-paper is to be 
burned and weighed, it must be perfectly freed from 
the acids by continuous washing. 

5. Pour ten or fifteen drops of the filtrate into a 
test tube. Drop in three or four drops of hydro- 
chloric acid. If a precipitate forms it may be of 
silver ; if so, it will grow dark violet on exposure 
to daylight, or more rapidly and darker in sunlight. 
Or to test more quickly, add strong ammonia, 30 to 
40 drops ; it dissolves after a short time ; or if it does 
not dissolve, then it is lead ; filter and test on 
charcoal with the blow-pipe ; if it gives, with inner 
flame, a bead and yellow incrustation around, it is 
lead. Or, if none of the above results are seen, and 
yet there is a precipitate, then it is mercury. To 
prove this, add a solution of carbonate of potash and 
digest ; it turns black ; filter and place it in a glass 
tube, heat gently with a blow-pipe ; it volatilizes 


and condenses on the sides; examine with strong 
lens, it is mercury. 

6. But suppose hydrochloric acid produces no 
precipitate though in excess and heated? Then 
there is neither lead, silver nor mercury in the 
assay, and it is not necessary to treat the ore for 
either, but proceed to the next step. It will be seen 
why we directed nitric acid to be poured on the 
assay, as in No. 2. Hydrochloric acid would have 
prevented these tests as given, but you are now 
prepared for the next metals, with three less to look 
for, or with a certainty as to the presence of one or 
more of the three. 

7. The whole assay, or its solution, may now be 
used. If any precipitate occurred in the test-tube, 
treat the whole assay solution with hydrochloric 
acid, heat to boiling, and separate the precipitated 
metal or metals in the whole, as in the test-tube, by 
nitration. Wash, set the paper (filter) aside under 
cover of paper to dry, and pass hydrogen sulphide 
slowly through the filtrate until the filtrate smells 
plainly of the gas. 

8. As this gas is frequently used, make a simple 
and cheap apparatus so that you may have a supply 
at any time, thus : Cut off the bottom of a long- 
bottle * of small diameter, D, say about two inches, 
and fit it into a fruit jar, E, as in Fig. 34. 

* Cut a nick, with a large file, in the spot where you wish to start 
a crack near the bottom, then heat a rod. or poker, or spike-nail, 
nearly red-hot, place it on the nick, a crack starts; draw your hot 
iron and the crack will follow; when nearly cracked around pull the 
bottom off. A glass chimney may be used, but it is rather too small 
to contain sufficient iron sulphide. 



The top A should be fitted loosely so that it may 
be removed and let air pass through. The cork at 
B must be air-tight. Fit a small tube into the cork 
after bending it in a spirit-lamp flame — a quarter- 
inch tube with an eighth-inch aperture is suffi- 
ciently large and is easily bent. Take an inch rod 
of iron, let the blacksmith heat it white-hot, and 
press it into a small roll of brimstone, this will give 
you iron sulphide — you need it in pieces as large 

Fig. 34. 

as bullets : it melts readily against the brimstone. 
Place some cotton in the neck of the bottle, and 
having fitted a plug of wood with holes in it for the 
bottom of the bottle, invert the bottle and fill it 
half full of iron sulphide lumps, fasten the wooden 
plug in the bottom, not very tightly, but tightly in 
three or four places, so that water can pass easily, 
and yet the plug be well fixed in. Put the bottle 
in its place, resting in the jar at A, and somewhat 
loosely fastened. But this must be after you have 
half filled the jar with a mixture of equal parts of 


common hydrochloric acid and rain-water (or, next 
best, well-water). Hydrogen sulphide will form 
immediately, and if you have made all connections 
perfectly, as in the figure, the gas will pass from 
this apparatus into the solution of ore in the beaker 
and precipitation will soon take place. The advan- 
tage of this apparatus is that if you tie two little 
blocks of wood against the sides of the India-rubber 
tubes, C C, so as to press the sides together and stop 
the gas from flowing, the gas forming pushes the 
water out of the interior glass D, and the gas stops 
forming, but is ready at any moment to begin as 
soon as the string around the little blocks is removed. 

9. After introducing the hydrogen sulphide until 
the filtrate smells of the gas, filter and wash the pre- 
cipitate, mark the paper containing it with the 
letter A, and put this precipitate aside for the 
present. This is the precipitate from the hydrogen 

10. The filtrate. If the strip of platinum 
shows that it contains some material after evapora- 
tion of a few drops, proceed by adding a solution of 
ammonium chloride (sal ammoniac), and then aqua 
ammonia to the filtrate, using about one-fifteenth 
or one-twentieth of the bulk. Then add ammo- 
nium sulphide so long as any precipitate is appar- 
ent. Let it stand awhile. This precipitate may 
contain alumina, chromium oxide, zinc, nickel, 
manganese, cobalt and iron as sulphides. It may 
likewise contain phosphates, borates, oxalates, and 
hydrofluorates of the alkaline earths (barium, stron- 
tium and lime). The latter we may not care for. 


11. Filter and wash this precipitate. Add a little 
water to the hydrochloric acid, now to be used in 
treating this precipitate. Add this diluted hydro- 
chloric acid in sufficient quantity to dissolve the 
precipitate, and put it aside to digest. If any part 
refuses to dissolve, it is because there may be 
present cobalt, or nickel, or both ; add nitric acid 
and boil, for these metals dissolve in hot nitro- 
hydrochloric acid. Filter. Next add to the whole 
solution ammonium chloride, and excess of aqua 
ammonia. The consequent precipitate may contain 
alumina, chromium oxide, sesquioxide of iron, and 
the alkaline earths, as phosphates, etc. Dissolve 
the precipitate by digesting in caustic potash solu- 
tion till all is dissolved that will dissolve. Filter. 
The solution may contain alumina and chromium 
oxide ; boil for some time, and if a precipitate is 
formed, it is chromium oxide ; confirm by the 
blow-pipe ; it gives a green bead with borax, height- 
ened by fusion with metallic tin or charcoal, which 
is the blow-pipe test for chromium. 

12. Now super-saturate the solution with hydro- 
chloric acid and boil with excess of ammonia ;* if a 
precipitate is formed it is alumina. Confirm with 
blow-pipe, as has been shown. What was dissolved 
by digestion with potassium hydroxide (caustic 
potash solution) has now been treated. The pre- 
cipitate may contain iron and more chromium 

*By "excess" is meant so much that after stirring with a glass 
strip or rod, the liquid smells strongly of ammonia. 


oxide, and the phosphates, etc., of the alkaline 

13. We will now proceed with a portion of this 
precipitate by first dissolving it in as small a quan- 
tity of hydrochloric acid as is possible, filter, and 
add to the solution (made as nearly neutral as pos- 
sible) two or three drops of ferro-cyanide of potash 
(yellow prussiate of potash in solution); a blue pre- 
cipitate is formed, proving the presence of iron 
sesquioxide. Wash another portion and fuse it in 
a small crucible with potassium nitrate (pure salt- 
petre) and sodium carbonate about equal parts. 
When cold digest with water ; a yellow solution 
results, which produces a yellow precipitate with 
acetate of lead, showing the presence of oxide of 
chromium. This double finding of chromium oxide 
(for it was found before) is due to the relative quan- 
tity of iron present as related to chromium oxide 
present, which will not be entirely precipitated 
at one time in the presence of iron under these 

14. We now go back to the solution filtered 
off from the precipitate treated of in paragraph 11. 
This solution may contain zinc, manganese, nickel 
and cobalt. Digest with ammonium sulphide, wash 
the consequent precipitate and dissolve it in nitro- 
hydrochloric acid (aqua regia). It may be dis- 
solved upon the filter by dropping the mixed acids 
and filtering through into a clean beaker, just as it 
could have been done in paragraph 11. This is 
convenient when the precipitate adheres too tightly 

90 prospector's field-book and guide. 

to the filter to allow of scraping it off entirely. 
Digest this clear solution with potassium hydroxide 
(or caustic potassa) precisely as in paragraph 11. 
This potassa may be put into the beaker in small 
pieces of the stick, in which form potassium hy- 
droxide generally is sold. 

(a) The solution may contain zinc oxide. 

(6) The precipitate may contain manganese, cobalt 
and nickel, as oxides. Pass hydrogen sulphide 
through the solution (a) until the precipitate (white 
zinc) has ceased to fall. Wash and agitate the pre- 
cipitate (b) with a solution of carbonate of ammonia. 
The precipitate which now falls is the carbonate 
of manganese — confirm this by the blow-pipe. The 
solution from this last treatment may contain cobalt 
and nickel oxides. Evaporate it to dryness, redis- 
solve in a few drops of hydrochloric acid, and again 
evaporate to a moist mass and divide the mass into 
two parts. Heat one portion with borax in the 
blow-pipe flame, a blue bead proves cobalt. Dis- 
solve the other portion in water and add solution 
of cyanide of potassium slowly, a precipitate is 
formed which, on continued adding of the potas- 
sium cyanide, begins to redissolve. On adding 
hydrochloric acid it is again precipitated. It is 
nickel. Confirm with the blow-pipe. 

15. In paragraph 9, paper A was put aside. 
This paper contained the precipitate holding the 
copper of the ore if any was present. Digest this 
with ammonium sulphide (or potassium sulphide). 
A solution and a precipitate are formed. The pre- 


cipitate may contain lead, mercury, bismuth, cad- 
mium, besides copper, as sulphides. The solution 
may contain gold, platinum, antimony, arsenic, and 
tin as sulphides. 

16. Treat the precipitate first, by boiling it with 
nitric acid. A black or brownish residue remains 
undissolved. Take a hard glass tube, and having 
washed and dried the black residue, introduce some 
of it into the tube and heat it. It may act in three 
ways : (a) it sublimes without change; mercury oxide 
was present — test with blow-pipe ; (6) it sublimes 
leaving a white powder which, when moistened with 
ammonium sulphide, turns black, proving it to be 
lead sulphate; (c) it sublimes, but as a mixture of 
mercury sulphide with minute globules of metallic 
mercury, showing that through some haste or lack of 
care, mercury as sub-oxide of mercury still remains 
when it should have been entirely precipitated as 
chloride of mercury at the first (paragraph 5). 

17. We now proceed with the nitrate (obtained as 
stated in paragraph 16), from the black or brownish 
residue. Treat this with solution of carbonate of 
potash and wash the consequent precipitate, and 
then digest this precipitate in cyanide of potassium, 
in excess, while it is moist. This may be done on 
the filter after changing the beaker, since this fil- 
trate or solution must be kept. The insoluble part 
may contain lead and bismuth as carbonates — the 
solution may contain copper and cadmium as double 
salts with cyanide of potassium. 

18. Proceed with the insoluble part by boiling it 

92 prospector's field-book and guide. 

with dilute hydrochloric acid. To one part of the 
resultant solution add sulphuric acid; the precipitate 
indicates lead. To the other part, after concentra- 
tion by evaporation, add a large quantity of water 
— a milkiness is produced indicating bismuth. 

19. Into the solution (paragraph 17), after digest- 
ing with potassium cyanide, pass hydrogen sulphide 
— the precipitate, if formed, indicates cadmium — test 
it with the blow-pipe. To the solution add hydro- 
chloric acid — copper sulphide will be precipitated ; 
add a few drops of nitric acid, which will dissolve 
the copper sulphide, and then by adding ammonia 
in slight excess the solution has a blue color indicat- 
ing copper. 

20. We are now to treat the solution mentioned in 
paragraph 15. The insoluble part, paragraph 16, 
having been separated off as there stated, add to the 
solution acetic acid, and boil. If a precipitate be 
produced, collect a small portion, wash and heat it 
over a spirit-lamp upon a strip of platinum foil. If 
it burns with a bluish flame and leaves no residue 
whatever, it is sulphur and nothing more may be 
done — this part of the assay is exhausted. But if it 
leaves some residue, then several important elements 
may be present. Proceed, and to one part add a 
solution of chloride of tin (protochloride with a 
drop of nitric acid added), a purple color is pro- 
duced. To another part add a solution of proto- 
sulphate of iron — a brown precipitate is produced 
indicating gold in both cases. 

To another part add ammonium chloride (solu- 


tion), a yellow crystalline precipitate falls which 
marks platinum. Arsenic may be tested by the 
blow-pipe in the ore, but if the presence of sulphur, 
in larger quantity, prevents detecting a small quan- 
tity of arsenic, it may be detected thus : Take a part 
of the black or brownish precipitate resulting from 
the addition of acetic acid, and mix it with three 
times its bulk of nitrate of potash (saltpetre) and 
carbonate of soda. Project this mixture, a little at 
a time, into a Berlin crucible, in which a mixture 
of the same substances has been placed and is in 
fusion over a lamp. At conclusion, digest the fused 
mass with pure water ; filter ; add excess of nitric 
acid and heat ; now add nitrate of silver; filter when 
cold, and add very dilute ammonia; a brown pre- 
cipitation or coloring marks arsenic. 

Dissolve another portion of the dark precipitate 
or residue from acetic acid in hydrochloric acid. 
Place in the solution a strip of metallic zinc — a 
pulverulent deposit takes place on the zinc, indi- 
cating antimony. If more proof be wanted remove 
the powder to a beaker and digest in nitric acid, 
when a white precipitate is formed. Digest it with 
a strong solution of tartaric acid, only a part may 
be dissolved, but filter; into the clear solution pass 
hydrogen sulphide and an orange-colored precipi- 
tate is formed, proving antimony. 

In the last paragraph it was found that a part of 
the precipitate was not dissolved in the tartaric 
acid ; dry it ; place it on charcoal with a little 
cyanide of potassium and carbonate of soda, and 


turn the inner flame of the blow-pipe upon it ; it is 
reduced to metallic tin. 

In the above analysis provision has been made 
for the detection of sixteen elements. Of course, if 
no precipitates or signs appear at any one stage of 
the analysis, proceed immediately to the next, for it 
is not probable that any mineral will ever contain 
even one-half the elements mentioned in the assay, 
but the full number is given so as to reach any 
possible case. 


We have given the wet assay method, and we 
now give as much of the dry assay as may generally 
be called for. v 

What will be first needed in the dry assay are 
crucibles, scorifiers and cupels. Crucibles for 
general purposes are made of coarse material, and 
are called Hessian. They are sold in nests of five 
or more. The only sizes of much value are those 
holding about 6 to 8 ounces. Scorifiers are flat, 
but thick, clay saucers intended to prepare the 
rough ore for the finer treatment by use of the 
cupel and in the assay furnace. The cupel is a 
little saucer of bone-ash, intended to be used on the 
floor or bottom of a heated muffle in the assay 
furnace. The muffle is a clay oven of small 
dimensions, intended to protect the scorifier and 
cupel from the coals of the furnace. They can be 
obtained at any chemical warehouse. 

An assay furnace may be made of sheet-iron; it 



Fig. 35. 

should be some 15 inches in diameter, with a grate 
near the bottom, and lined with either ordinary or 
fire brick. 

In the accompanying figure 35 is given the gen- 
eral form of one which has been used for years with 
perfect success. 

A plain sheet-iron cylinder (Fig. 35) 18 inches 
high and 15 inches in diameter, with draft hole at 
A, muffle hole at B, and pipe- 
hole at C, and lined, as has been 
said, with brick, will answer all 
purposes of the best assays. The 
hole at C must have a collar 
and pipe either for a chimney 
or it must enter a chimney. B 
must be provided with a flanged 
door, as also the draft hole A. 
The top may have, loosely laid 
on, only a square sheet of heavy 
sheet-iron, and the whole placed 
upon a flat stone or few bricks. Several heavy 
bars of iron nicked into the bricks will answer 
where there is no iron foundry at hand to cast a 
grating D. Charcoal or coke may be used, or, 
where the draft is strong, a hard coal. 

The crucible should be lined with charcoal finely 
pulverized and made pasty with molasses or any 
syrup. This process is called "brasquing." Heat 
the crucible before using, to dry out the syrup. 

For field testing a small portable assay furnace, 
using preferably some form of gaseous fuel, is of 

- © - 

"" B 


96 prospector's field-rook and guide. 

great advantage. Such a furnace is made by E. 
H. Sargent & Son, of Chicago, Illinois. It has the 
advantages of only weighing 7 lbs., being about 5 
by 8 inches, when set up is about 20 inches in 
height, and it packs in a space of 1 cubic foot with 
all the necessary material — the box then weighs 
ready packed, some 25 lbs. (without mortar and 
pestle); and lastly, one of the greatest recommenda- 
tions is that refined petroleum is used as the fuel. 
This form of fuel is much more easily obtained, and 
is less dangerous than gasolene, which is the liquid 
fuel most commonly used for assaying. 

If the object is to obtain the amount of iron in 
an ore, pulverize the ore to about forty to the inch, 
weigh it, mix it with charcoal and cast the mixture, 
from a piece of paper, on the bottom of the crucible, 
cover it with charcoal an inch or two deep, drop in 
two or three pieces of brick, and place the crucible 
in the hottest part of the fire, cover all with coal 
and gradually increase the heat and keep it nearly 
at white heat for half an hour, draw it out, jar the 
crucible down on a stone to settle the melted 
button. When cool take out the contents, and the 
metallic iron will be found with its slag attached. 
Clean the button, weigh it, and the weight of the 
ore used is to the weight of the button as 100 is to 
the per cent, of iron in that ore ; that is, multiply 
the weight of the button by 100 and divide by the 
weight of the ore used. 

Scales, Weighing, etc. Any scales that weigh 
from J oz. to \ lb. or a greater amount will serve 


for the rough work in the field. The cheapest and 
lightest scale is one used for weighing letters, which 
weighs from J oz. to 12 ozs.; but a better scale is 
a light spring balance, weighing up to 2 lbs., and 
divided into J and J ozs. 

The sample can best be weighed by laying it on 
a sheet of paper, turning up the edges, and tying 
them with a piece of string which can be hooked 
on to the scales. 

For more delicate work, a small pair of scales 
weighing to -rio^ n of a grain is quite sufficient. 
Such scales may be bought at any chemical ware- 
house, made to pack and carry with ease and secur- 
ity. When in a fixed laboratory at home, the 
scales weighing to 0.0077 grain or half a milligram 
will save chemicals, time and work ; but unless the 
analyst has an absolutely true average of the ton of 
ore most carefully chosen, the smaller the amount 
of ore used the more likely is the assay to prove 
deceptive when proportioned to the ton. 

Pulverization for the dry method should never 
be more than 50 or 60 to the inch. Smaller par- 
ticles are apt to be lost or separated in the crucible. 
Obtain a piece of silk bolting cloth from a flour 
miller or from the source from which he gets his 
cloth, and select two or three grades, one for " wet 
analysis," which may be as fine as 80 to the inch. 
Have a rim made by the tinner to tie on the siev- 
ing cloth, or use a cracked beaker glass, cutting it 
off by the method we have already given. (See 
previous note, page 85.) 


Gold and Silver Ores. These ores require pre- 
paration in the scorifier. Powder the ore. Take 
about 50 grains of the powdered ore, 500 to 1000 
grains of lead shavings, according to the probable 
amount of silver, and about 50 grains of borax. 
Mix the ore with half the lead and place the mix- 
ture in the scorifier, spread the other half of lead 
over the contents, and finally spread the borax over 
all. Put the scorifier in the muffle, close the door, 
and heat up to fusion — then the door should be 
partly opened, the heat increased, until the oxidized 
lead (litharge) covers the scorifier. Take the latter 
from the muffle and pour the contents into an iron 
cavity or mould, separate the button and hammer 
it into the shape of a cube. It is now ready for 
cupellation as it contains all the gold and silver. 

Cupellation. By this process the lead is simply 
separated from the gold and silver, the separation 
being effected both by absorbing and oxidizing. 
Cupels may be made by operator, but they can be 
bought so cheaply that it is seldom worth the 
trouble to make them. 

Push a cupel into the heated muffle, place the 
cube of lead in the cupel with little tongs, and heat 
up till the lead melts, watch the lead gradually 
wasting away until reduced to the size of the silver 
it contains, when the surface will become instan- 
taneously bright and nothing remains but the silver 
containing the gold. Withdraw the cupel and cool 
and weigh the ball. The gold and silver must be 
separated by the wet process, thus : Dissolve the ball 


in strong nitric acid with heat till the acid boils ; a 
dark powder precipitates ; filter off the dark powder, 
it is the gold, and precipitate the silver by solution 
of common table salt or by hydrochloric acid. After 
all is precipitated drop into the white precipitate 
some pieces of zinc, add more hydrochloric acid — 
hydrogen gas is generated, which reduces the white 
silver chloride to powdered metallic silver. The 
gold and the silver may now be melted in separate 
crucibles, weighed and compared with the amount 
of ore used. 

In these trials the lead should first be cupelled 
for its silver, and that substracted from the silver 
found, as almost all leads contain some silver. 

If it should be more convenient to melt the ore 
in a crucible rather than a scorifier, use the follow- 
ing flux : If the ore is composed chiefly of rock, pul- 
verize, take 100 to 500 grains of ore, red lead 500 
grains, charcoal powder 20 to 25 grains, carbonate 
of soda and borax together 500 grains — the more 
rock the more carbonate of soda, the more metallic 
bases the more borax. Place a little borax over all 
and melt till all is liquid, requiring about 20 min- 
utes ; withdraw, extract the button when cool, ham- 
mer up to a cube and cupel. Separate the gold and 
silver as before, but remember that the amount of 
silver must be three times that of the gold, and if 
there is reason to believe that there is not this 
amount, some silver must be melted with the 
button, since the separation will not otherwise be 

T. S. G. Kirkpatick recommends the following 
process of assaying gold quartz : Take 200 grains of 
ore, 500 of litharge, 6 of lamp-black and 500 of car- 
bonate of soda; or, 200 grains of ore, 200 of red 
lead, 150 of carbonate of soda, 8 of charcoal and 6 
of borax. Mix and put into a warmed crucible, 
and cover with half an inch of common salt. Fuse 
in a hot fire 30 minutes ; cool and break the pot ; 
clean the button with a small hammer. 

If the quartz is very pyritous, take 100 grains 
and calcine " dead " without clotting, add 500 grains 
of red lead, 35 of charcoal, 400 of borax, and 400 of 
carbonate of soda, cover with salt and proceed as 
above. In each case cupel the button. 

As the bone ash of which the cupel is made can 
absorb its own weight of metallic oxides, the cupel 
chosen should always exceed the weight of the 
button to be operated on, so as to have a margin. 
Boil the gold prill obtained from cupelling in nitric 
acid, which dissolves the silver and leaves the gold 

The above formula are open to modifications by 
the operator according to the apparent richness or 
poverty of the ore to be treated, and the presence 
and character of the basic impurities. In case there 
are oxides, a reducing agent is required ; and if 
sulphides, an oxidizing agent. As a rule, employ a 
weight of litharge twice that of the ore, and of car- 
bonate of soda the same as the ore. These reagents 
are added to control the size of the lead button, and 
to obtain one of suitable size for cupelling. 


Lead Ore, Galena. The charge for the cru- 
cible is carbonate of soda, two or three times the 
weight of the ore, three or four tenpenny nails on 
top to absorb the sulphur, and a covering of salt or 
borax ; heat to redness about 20 minutes. Pour 
the contents into a crucible and separate the button. 

Copper Ore. The wet assay is better than the 
dry, especially that by the burette, which we shall 
give later on under " Copper." 

Tin Ore. If it is mixed with iron or copper 
pyrites it should be powdered and roasted, and then 
mixed with one-quarter of its weight of charcoal 
and subjected to great heat in a crucible for about 
20 minutes. Jar it as in an iron assay, let it cool, 
and pick out the button or buttons, or pour it out 
while melted. 

It may be reduced otherwise by melting the pow- 
dered ore with cyanide of potassium, 100 grains of 
ore to 600 grains of cyanide. Cool, extract button. 

This ore is very hard and may be powdered to 
60 to the inch. 

Mercury. These ores are easily reduced by 
simply heating and condensing the vapors in a cold 
bath as in using a retort and cool receiver. 

Antimony. Place about 2000 grains of ore pow- 
dered in a crucible having a hole chipped out in 
the bottom, and the hole stopped loosely with a 
piece of charcoal. Put this crucible into another 
half-way down. Then lute on the lid and put clay 
around the juncture of the two and put live coals 
around the upper crucible by placing some broken 

102 prospector's field-book and guide. 

bricks around the lower one on the grate, to keep 
the coals away from it. The antimony will melt 
and leave its gangue rock in the upper crucible 
while the lower one will receive the melted metal. 

Bismuth, zinc, manganese, nickel, cobalt, and 
other metals should be reduced or analyzed by the 
" wet process " which we have already given. (In 
this chapter, V.) 

An excellent fire lute is made of 8 parts of sharp 
sand, 2 parts of good clay, 1 part horse-dung ; mix 
and temper like mortar. 




We shall now proceed to a more definite and 
practical treatment of these two subjects, technical 
mineralogy and economic geology, so far, only, as 
they may be of service in the work before us. 

The first suggestion which may be made is that 
the best preparation for the general study of miner- 
alogy is to gather a collection of the chief mineral 
substances with which the student is to come in 
contact. In many cases very small specimens are 
sufficient. As we proceed in our treatment of each 
substance it will occur to the reader what and how 
much he needs to obtain. But it should be empha- 
sized that no amount of study on the part of the 
student, nor of description on the part of the in- 
structor, can ever take the place of the actual spe- 

Gold. — Gold is one of the most widely distributed 
metals, but generally speaking, accumulations of 
larger quantities of it are found only in a few local- 
ities. Traces of it pass from various ores into arti- 
ficial products, for instance, into litharge, minium, 

* For list of specimens, see end of book. 



white lead, silver and copper and coins made there- 
from, etc. Minute quantities of gold (about 13 
grains in 1 ton) have been found even in sea water 
as well as in clay deposits. 

The chief supplies of gold are at the present time 
obtained from the United States (California, Nevada, 
Arizona, Montana, Utah, Alaska, Colorado) from 
British Columbia, Nova Scotia, Mexico, Peru and 
Brazil, from Australia (especially Victoria, New 
South Wales, and Queensland), Tasmania, New 
Zealand, and in Africa (Natal, the Transvaal, etc.). 
The Ural Mountains and Siberia also yield consid- 
erable gold. In Europe only Transylvania and 
Hungary are of any importance. 

Gold occurs almost exclusively in the metallic 
state, either in situ, in quartz rock, especially along 
with quartz, pyrites and hydroferrite ; also as gold 
sand, in dust or grains, leaflets and rounded pieces 
(nuggets), in the sands of rivers or in alluvial soils, 
consisting chiefly of clay and quartz sand along 
with mica, water-worn fragments of syenite, chlorite 
slate, grains of chrome iron and magnetic iron, 
spinel, garnet, etc. In the metallic state it contains 
always more or less silver as electrum. According 
to recent analyses native gold contains : 

Transyl- South 

vania. America. Siberia. California. Australia. 

Gold 64.77 38.14 86.50 90.00 99.2 and 95.7 

Silver • . 35.23 11.96 13.20 10.06 0.43 " 3.8 

Iron and other metals. — — 0.30 0.34 0.28" 0.2 

Siberian, Californian and Australian gold con- 

GOLD. 105 

tain not unfrequently osmiridium, palladium and 
platinum. Mexican rhodium-gold contains 34 to 
43 per cent, rhodium. Gold amalgam is found in 
California and Columbia. The so-called black gold 
which occurs in nuggets in Arizona and at Maldon, 
Victoria, in granite and quartz lodes, is crystalline 
and silver-like when freshly fractured, but soon 
turns black in the air. It is bismuth-gold, with 
64.211 gold, 34.398 bismuth and 1.591 gangue. 
Gold is also often met with in native tellurium and 
silver telluride, sometimes in iron pyrites, copper 
pyrites, in blende, in arsenical pyrites, and galena. 
To detect a content of native gold in pyrites bring 
a few drops of mercury into a porcelain crucible, 
put a perforated piece of cardboard in the crucible 
so that it rests a short distance above the mercury, 
place a small package of pyrites over the hole in 
the cardboard, heat the crucible for some time and 
watch with the pocket lens for the appearance of 
white stains of gold amalgam, which on rubbing 
with a brush or feather becomes lustrous. 

Gold crystallizes in the isomeric system, but 
crystals are seldom found. Figs. 36 and 37 repre- 
sent gold crystals. Twin crystals are also occasion- 
ally found. In Sonora, California, Blake found 
gold in hexagonal prisms. Fig. 38 shows the 
finest gold dust 700 times magnified, and Fig. 39 a 
reduced illustration of a lump of gold which was 
found at Forest Creek, Victoria, Australia. It 
weighed more than 30 pounds, and was 11.33 
inches long and 5.15 inches wide. The largest 



nugget of gold ever found was at Ballarat, Australia. 
It weighed over 191 pounds, and was 20 inches long 
and 9 inches wide. 

The specific gravity of gold is 16 to 19.5, accord- 

Fig. 36. 

Fig. 37. 

Fig. 38. 

ing to the amount of alloy ; hardness 2.5 to 3.0. It 
is the only yellow, malleable mineral found in the 
natural state. Its color varies from pale to deep 
yellow. In some localities, such as in New South 

Fig. 39. 

Wales, Australia, and Costa Eica, it is often found 
of a very light color, but it presents the same color 
from whatever direction it is looked at, and to the 
prospector this is a guiding test. Indeed one of the 

GOLD. 107 

most important and useful accomplishments for 
gold exploitation is " an eye for color." Native 
gold possesses a peculiar color which is readily re- 
cognized, although the gold may be alloyed with 
silver or copper, and its color will in an instant dis- 
tinguish it in the eye of the expert from any condi- 
tion of pyrites, whether iron or copper pyrites. 

Gold grains will always flatten when struck with 
a hammer or between two stones, whereas other 
minerals similar in color will break into fragments. 
Or if the doubtful particle is coarse enough, take a 
needle and stick the point into the questionable 
specimen. If gold, the steel point will readily prick 
it ; if pyrites or yellow mica, the point will glance 
off or only scratch it. 

Under the blow-pipe, on a piece of charcoal, gold 
may melt, but on cooling it always retains its color ; 
any other mineral will lose color, become black- 
ened, or will be attracted to the end of your pen- 
knife blade, if that blade has been previously 
magnetized, and the unknown substance contains 

Gold imparts no color to boiling nitric acid. It 
will not dissolve in nitric or hydrochloric acid 
separately, but it does dissolve in the two when 
combined, and then the acid is known as nitro- 
muriatic acid or aqua regia. Proportions : one 
nitric to four muriatic. 

But it is not always a trustworthy sign that par- 
ticles are gold because they will not dissolve in 
nitric acid. Some seemingly gold-colored particles 

will not dissolve in nitric acid, and yet contain not 
a trace of gold. 

The simplest instrument for the discovery of gold 
and the estimation of the value of an auriferous 
material in which the gold is contained in a free 
state, is the ordinary miner's pan, a circular dish of 
Russian sheet-iron, about 12 inches wide and 3 
inches deep, with sloping sides. There should be a 
slight indentation all round where the sides join 
the bottom, so as to afford lodging for the gold 
grains, and the more rusty it is the better. A fry- 
ing pan free from grease will answer very well on a 
pinch. The South American batea, Fig. 40, made 

Fig. 40. 

of hard wood in a solid piece, and hollowed out like 
a shallow funnel, is a superior implement when in 
capable hands. Another good substitute for this 
pan is a kind of magnified shovel without handle 
made of linden wood and provided with a vertical 
wall on three sides. The wooden implements 
should be slightly charred on the surface to show 
up the gold grains, and should not have been used 
to hold mercury or amalgam. 

The object of panning out, as the operation with 
the pan or batea is called, is to settle and collect at 
the bottom of the pan the heaviest portions of the 

GOLD. 109 

material subjected to the test. Simple as the pro- 
cess of panning appears to be, dexterity is only ac- 
quired by considerable practice. In outline the 
operation is as follows : 

A quantity of the dirt to be washed is placed in 
the pan, sufficient to occupy about two-thirds of its 
capacity. The pan with its contents is then im- 
mersed in water, either in a hole or in a rivulet, of 
such a depth that the operator can conveniently 
reach the pan with his hands while it rests on the 
bottom. The object of this is to give him free use 
of both his hands for stirring up the mass, so that 
every particle may become thoroughly sodden and 
disintegrated. Of course the pan may be held in 
one hand, and its contents stirred with the other, 
but the disadvantages of such a method are obvious. 

When the dirt has become thoroughly soaked and 
permeated by the water, the pan is taken in both 
hands, one on either side, and a little inside of its 
greatest diameter, and without allowing it to emerge 
from the water, it is suspended in the hands, not 
quite level, but tipping somewhat away from the 
person. In this position it is shaken so as to allow 
the water to disengage all the light earthy particles 
and carry them away. When this has been con- 
cluded there will remain in the pan varying pro- 
portions of gold dust, heavy sand, lumps of clay, 
and gravel stones. These last accumulate on the 
surface, and are picked off by hand and thrown 
aside. The lumps of clay must be crumbled and 
reduced by rubbing, so as to be carried off by the 


water during the next immersion of the pan. A 
neat turn of the wrist is required to allow the 
muddy waters to escape in driblets over the de- 
pressed edge of the pan, without exercising so much 
force as to send the lighter portion of the gold after 
them. At last nothing remains in the pan but the 
gold dust, with usually some heavy black sand and 
a little earthy matter. By the final careful wash- 
ing with plenty of clean water, the earthy matters 
can be completely removed, but the heavy iron sand 
cannot be got rid of by any method based upon its 
specific gravity relatively to that of gold. 

To remove the iron sand, one of two simple plans 
has to be adopted. If the sand be magnetic, as is 
usually the case, it may be eliminated to the last 
grain by stirring the mass carefully with a powerful 
magnet, care being taken that no particles of gold 
become mechanically suspended among the black 

Where this is ineffectual, recourse must be had to 
blowing. For this purpose the mass of gold dust 
and iron sand is allowed to become perfectly dry, 
and small quantities of it at a time are placed in an 
instrument called a blower — a sort of a shallow 
scoop, made of tin and open at one end. Holding 
the blower with its mouth pointed away from him, 
and gently shaking it so as constantly to change the 
position of the particles, the operator blows gently 
along the surface of the contents, regulating the 
force and direction of his breath so as to remove the 
sand without disturbing the gold. Where water 



can be had, a pan is the most efficient instrument a 
man can travel with in his gold-seeking journeys. 

A crude apparatus formerly much used in Cali- 
fornia and Australia is called the cradle or rocker. 
This, as shown on Fig. 41, is a trough of some 7 
feet in length and 2 broad. Across the bottom 
of this several bars are nailed at equal distances, 
and at the upper end a kind of sieve is fixed at about 
a foot above the bottom. This whole arrangement 

Fig. 41. 

is mounted upon rollers. To operate the apparatus 
four men are required. One man digs out the 
earth from the hole, a second supplies the cradle 
sieve with this auriferous earth, a third keeps up a 
supply of water which he pours upon the earth in 
the sieve, while a fourth keeps the machine contin- 
ually moving upon the rollers. The large stones 
washed out are removed by hand from the sieve, 



and the water at the same time washes the smaller 
substance through, which is slowly carried towards 
the lower end of the trough by a slight inclination 
given to the whole. Thus the flow of water tends 
to keep the earthy particles in suspension so as to 
allow of their washing off, while the heavier por- 
tions of gold are obstructed in their flow, and re- 
tained against the cross bars fixed to the cradle 
bottom. These are removed from time to time and 
dried in the sun, when, after blowing away lighter 
particles, the metal only further requires to be 

A more efficient apparatus is the long torn, Fig. 

Fig. 42. 


42. A torn that will serve the purpose of the pros- 
pector can be easily manufactured on the spot where 
it is decided to test the ore of a newly discovered 
reef. A serviceable supply of tools must of course 
be comprised in his outfit, including one or two 
good adzes for giving a smooth plank surface to the 
side of the timber which forms the floor or sides of 
the torn. A rough but quite efficient apparatus can 
by this method be constructed in a short time, 

GOLD. 113 

The torn consists essentially of two separate 
troughs as shown in the figure. These are placed 
on an incline, or given an inclination by log or 
rock supports. The California torn is about 12 feet 
long, 20 inches wide at the upper end, and widen- 
ing gradually to 30 inches at the mouth. A stream 
of water flows in by the spout just over the place 
where the dirt is introduced into the upper box or 
torn proper. The dirt is constantly thrown in by 
one man, while a second is occupied in stirring it 
about with a square-mouthed shovel, or a fork with 
several blunt prongs, which is useful for pitching 
out the heavy boulders that sometimes occur, and 
for tossing back undissolved lumps of clay against 
the current. The lower end of the torn is cut off 
obliquely, so that the mouth may be stopped by a 
sheet of perforated iron. The sheet of iron should 
be closely perforated with one-half inch holes — or 
smaller if the pay dirt is very fine — about 20 inches 

The apparatus being placed on an incline amount- 
ing generally to 12 inches, the materials all gravi- 
tate with the water towards this sloping grating at 
the mouth, everything passing through it except 
the large stones which gather on the grating, and 
are removed as often as necessary. Beneath this 
grating stands what is called -the riffle box into 
which all the fine matters, including the gold de- 
scend. The riffle box, like the torn proper is made 
of rough plank, and is also placed on an incline, 
but only just so that tb§ wa.ter passing oyer it will 


allow of the bottom becoming and remaining cov- 
ered with a thin coating of fine mud. In this way 
the gold and a few of the heaviest minerals will find 
their way to the bottom and rest there, especially 
by the help of the riffle bars, which give their name 
to the apparatus. Sometimes a little mercury is 
put behind the riffles, so as to assist in retaining 
the gold, and occasionally the riffle box is supple- 
mented by a series of blankets, which are useful for 
catching the very fine gold. 

The torn is cleaned out periodically, and the gold 
and amalgam are panned out. The torn employs 
two to four men according to the character of the 
dirt and the supply of water. It is applicable to 
diggings where the gold is coarse, it being quite in- 
capable of saving all fine gold, of which at least 10 
per cent, may be estimated as lost. 

The amalgam and mercury taken out must be 
pressed through buckskin or canvas to remove the 
excess of mercury, which will run into a vessel 
placed to catch it. The remaining sponge-like mass 
of amalgam must be retorted to extract the gold. 

Washing the dirt is also affected by sluices having 
an inclination of about 8 feet in 12 feet. These 
sluices consist of a series of troughs formed by 
planks nailed together, the length of each being 
about 10 or 12 feet, the height 8 inches to 2 feet, 
the width 1 to 4 feet. By making one end. of the 
bottom plank of each trough 4 inches narrower 
than at the other, the troughs can be telescoped into 
one another and so a sluice of very great length can 



be formed. Across the inside of the bottom-planks, 
small, narrow strips of wood 2 inches or so thick, 
and 3 or more inches wide, are fixed across, or some- 
times at angles of 45° to the side of the trough, 
at short intervals apart. Running water washes 
downward the earth thrown into the sluice, which 
is open on the top side, and the gold dust accumu- 
lates, sometimes assisted by the aid of mercury 
allowed to trickle out of a vessel from riffle to riffle, 

Fig. 43. 

in front of the bars, while the lighter matter is 
washed downwards. 

A still more effective method is what is called 
hydraulic mining, and under favorable circum- 
stances, such as a plentiful supply of water with 
good fall and extensive loose auriferous deposits, a 
very small amount of gold to the ton can be made 
to give paying returns. The water is conducted in 
flumes or pipes to a point near where it is required, 
thence in wrought-iron pipes gradually reduced in 

116 prospector's field-book and guide. 

size and ending in a great nozzle somewhat like 
that of a fireman's hose. Figs. 43 and 44 show the 
arrangement. Fig. 43 exhibits the mouth-piece 
movable at A B in an ascending, and at C D in an 
inclined, direction. E is a lever loaded with 

■ScO/fa*^ ,.-. 

weights, which facilitates the adjustment of the 
mouth-piece by the operator in any direction. The 
method of operating the arrangement will be seen 
from Fig. 44. A is the water-distributor, B the 
nozzle, C channels for carrying off the debris de- 
tached from the ledge ; D, piles of larger pieces of 

GOLD. 117 

rock which are finally comminuted. Tis a tunnel 
through which the water reaches the gutter, pro- 
vided with the grating F through which the finer 
stuff falls into the shallow settling basin E, and is 
distributed by blocks G, while the principal mass of 
water with the coarser material passes over the 
grating F into the principal sluice in which the 
grating H retains the larger pieces which are then 
thrown out at /. The basins E and the principal 
sluice are paved with wooden blocks or stones be- 
tween which mercury is placed. The amalgam 
formed is freed from admixtures in a mercury bath, 
pressed through sail-cloth, boiled in sulphuric acid 
and distilled. 

On nearly all alluvial gold fields, whether shal- 
low placers or deep leads, is found a stratum of 
ferruginous conglomerate, composed principally of 
rounded and angular fragments of quartz of all 
sizes, cemented together by the oxide of iron with 
which the mass is impregnated, and often so hard 
as to resist everything but blasting. This cement, 
as it is called, overlies the bed-rock, in some places 
resting on it, in others several inches or even feet 
above it. In thickness it fluctuates, from 6 inches 
to 8 feet or more. Its character varies but little. 
It is often highly auriferous, and is worthy of special 
attention. It should be pounded to a fine powder 
and tested. 

Many particles of fine gold, notwithstanding 
their greater specific gravity exhibit the tendency 
to float in water when undergoing a washing pro- 

118 prospector's field-book and guide. 

cess. To save this fine flour or float-gold, as it is 
called, experiments have shown that by heating the 
water to the boiling-point or nearly so, these float- 
ing particles of gold will subside to the bottom of 
the pan or vessel. 

Burning and Drifting. The labor of removing the 
barren gravel which overlies the pay dirt is very 
great, but ordinarily this is undertaken when the 
thickness is not considerable. With increasing 
thickness a point is soon reached where the task of 
removing it becomes so formidable that the miner 
will not make the attempt unless he believes that 
there is rich pay dirt beneath. In this event the 
practice is adopted of sinking shafts through the 
barren material to the pay dirt, and extracting the 
pay dirt by means of tunnels or drifts along the sur- 
face of the bed-rock. This method of working has 
been adopted only lately, but promises to be very 
important. The ordinary methods of sinking/drift- 
ing, timbering, stoping, etc., have been peculiarly 
modified in the Forty-mile District, Alaska, on ac- 
count of the exceptional character of the climate, 
and these modifications have spread from this dis- 
trict over the rest of the gold diggings. Owing to 
the severity and length of the winters the gravels 
are frozen during seven or eight months of the year. 
The miner who desires to sink a shaft waits until 
the cold season arrives, and then sinks through the 
frozen ground, which is so firm that the shafts or 
drifts do not need timbering for the sake of support. 
In sinking or drifting, instead of employing powder 

GOLD. 119 

and pick, as elsewhere, a small fire is built at the 
bottom of the shaft which is being sunk, or at the 
face of the drift which is being run, and thus the 
gravels are thawed out for some distance and can be 
easily taken up and brought to the surface. It takes 
a surprisingly small amount of wood to run a drift 
through the frozen gravel for a long distance. In 
this way the pay dirt is extracted and accumulates 
on the surface until spring, when it is shoveled into 
sluices and the gold is separated by washing, pan- 
ning, blowing and amalgamation in the manner pre- 
viously described. One large chamber or "stope" 
thus excavated in the gravels of Miller Creek in the 
Forty-mile District, is said to have measured 64 by 
32 feet, and 19 feet in height, with only 8 feet of 
barren gravel between it and the surface ; and yet 
this stood firmly until spring, when the gravels 
thawed and the stope caved in. 

For lode prospecting a pestle and mortar should be 
carried. The handiest for traveling is a mortar 
made from a mercury bottle cut in half, and a not 
too heavy wrought-iron pestle with a hardened face. 
To get the stuff to regulated fineness a fine screen is 
required, and the best for the prospector who is 
often on the move, is made from a piece of cheese 
cloth stretched over a small hoop. It is often 
desirable to heat the rock before crushing, as it is 
thus more easily triturated and will reveal all its 
gold. Having crushed the gangue to a fine powder, 
proceed to pan it off in the same manner as washing- 
out alluvial earth, except that in prospecting quartz 

one has to be much more particular, as the gold is 
usually finer. Take the pan in both hands and 
admit enough water to cover the pulverized sub- 
stance by a few inches. The whole is then swirled 
around and the dirty water poured off from time to 
time till the residue is clean quartz sand and heavy 
metal. Then the pan is gently tipped and a side to 
side motion given to it, thus causing the heavier 
contents to settle down in the corner. Next the 
water is carefully lapped in over the side, the pan 
being now tilted at a greater angle until the lighter 
particles are all washed away. The pan is then 
once more righted and very little water is a few 
times passed over the pinch of heavy mineral, when 
the gold will be revealed in a streak along the 
bottom. In this operation, as in all others, only 
practice will make perfect, and a few practical les- 
sons are worth whole pages of written instruction. 

J. C. F. Johnson * gives the following directions 
for making an amalgamating assay that will prove 
the amount of gold which can be got from a ton of 
a lode. Take a number of samples from different 
parts, both length and breadth. The drillings from 
the blasting bore-holes collected make the best test. 
When finely triturated weigh off one or two pounds, 
place in a black iron pan (it must not be tinned) 
with 4 ounces of mercury, 4 ounces common salt, 4 
ounces soda, and about half a gallon of boiling water. 
Then with a stick, stir the pulp constantly, occasion- 

* " Getting Gold." London, 1897. 

GOLD. 121 

ally swirling the dish as in panning off, till you feel 
certain that every particle of the gangue has come 
in contact with the mercury. Then carefully pan 
off into another dish so as to lose no mercury. 
Having got your amalgam clean, squeeze it through 
a piece of chamois leather, though a good quality 
of new calico previously wetted will do as well. 
The resulting pill of hard amalgam can then be 
wrapped in a piece of brown paper, placed on an 
old shovel, and the mercury driven off over a hot 
fire. Or a clay tobacco pipe, the mouth being 

Fig. 45. 

stopped with clay, makes a good retort. To make 
such a retort, Fig. 45, take two new tobacco pipes 
similar in shape, with the biggest bowls and longest 
stems procurable. Break off the stem of one close 
to the bowl and fill the hole with well-worked clay. 
Set the stemless pipe on end in a clay bed, and fill 
with amalgam, pass a bit of thin iron or copper 
wire beneath it, and bend the end of the wire 
upwards. Now -fit the whole pipe, bowl inverted, 
on to the under one, luting the edges well with clay. 
Twist the wire over the top with a pair of nippers 


till the two bowls are fitted closely together, and 
you have a retort that will stand any heat neces- 
sary to thoroughly distill mercury. The residue, 
after the mercury has been driven off, will be re- 
torted gold, which, on being weighed and the result 
multiplied by 2240 for 1 pound assay, or by 1120 
for two pounds, will give the amount of gold per 
ton which an ordinary battery might be expected 
to save. Thus 1 grain to the pound, 2240 pounds 
to the ton, would show that the stuff contained 4 
ounces, 13 pennyweights, 8 grains per ton. 

Darton's gold test. Darton remarks that a num- 
ber of methods have been proposed to detect the 
minute quantities of gold occurring in rocks, etc., 
and having examined and tested every method, re- 
commends the following as requiring but little time 
and being very trustworthy. 

Small parts are chipped from all the sides of a 
mass of rock amounting in all to about J oz. This 
is finely powdered in a steel mortar, and well mixed. 
About half of it is placed in a capacious test tube, 
and then partly filled with a solution made by dis- 
solving 20 grains of iodine and 30 grains of iodide 
of potassium in about 1 J ozs. of water. 

The mixture thus formed is thoroughly agitated 
by shaking and warming. Then after all particles 
have subsided, dip a piece of pure white filter paper 
in it, allow it to remain for a moment, then let it 
drain, and dry it over the spirit lamp. It is then 
placed upon a piece of platinum foil held by pincers, 
and heated to redness over the flame. The paper 

GOLD. 123 

is speedily consumed, and after heating further to 
burn off all carbon, it is allowed to cool, and then 
examined. If at all purple, gold is present in the 
ore, and the relative amount may be approximately 
deduced as much, fair, little or none. There is no 
compound which would be formed from natural 
products by this method which would mislead by 
staining the ash to a color at all similar to the dis- 
tinctive purple of finely-divided gold. 

A variation of this test is given by Thorpe and 
Muir in " Qualitative Chemical Analysis " as follows: 

Five or ten grains of the finely powdered mineral 
are shaken with alcoholic tincture of iodine, pre- 
pared by dissolving J oz. of iodine and J oz. of 
iodide of potassium in 1 pint of rectified spirit. 

The insoluble matter is allowed to settle, a piece 
of Swedish filter paper is dipped into the solution 
and incinerated after drying. If the ash be purple 
in color, gold is present. To confirm the presence 
of gold, treat the ash with a few drops of aqua 
regia, evaporate to dryness at a gentle heat, and 
dissolve the residue in water. Pour this solution 
into a beaker which is set upon a sheet of white 
paper. A solution is now prepared by adding ferric 
chloride to stannous chloride until a permanent 
yellow color is produced. This solution is diluted, 
a glass rod is dipped into it, then into the gold 
solution. A bluish purple streak in the track of 
the rod confirms the presence of gold. 

Occurrence of Gold in other Forms. Beside in the 
condition of simple native gold, this metal is found, 

124 prospector's field-book: and guide. 

as previously mentioned, in intimate mixture with 
pyrite (iron sulphide). It does not seem to be a 
compound, but, as we have said, a mixture or 
minute association. This seems evident from the 
fact that when the sulphur is removed from the 
pyrite and the iron rusts down, the gold particles 
appear with their own color and characteristics in 
cavities of various rocks, which, when crushed or 
water-worn, release the particles or pieces to be 
washed down and mingled with sands and gravels 
of lower levels, or perhaps the beds and channels 
of rivers. This is " placer gold." Where gold has 
not yet been thus released, it is found in association 
with iron, and especially with quartz in veins. In 
some instances the gold in quartz is disseminated 
in particles so exceedingly fine as to require the 
lens to reveal it. 

Nevertheless quartz is not the only mineral which 
contains gold, although it is the world's great pay- 
ing source of gold. Some of the other minerals 
contain it. It is found in yellowish-white, four-sided 
prisms, and in small white grains as large as a pea, 
and easily crumbles. In this condition the gold is 
amalgamated with quicksilver in the proportion of 
38 gold to 57 quicksilver, and is known as "gold 
amalgam." It is very easily tested by heating upon 
a piece of charcoal by a blow-pipe, when the quick- 
silver volatilizes and the gold remains. 

Gold in paying quantities is found in numerous 
combinations, and must be discovered and extracted 
either chemically, by the " wet method," or by assay- 

GOLD. 125 

ing in the crucible by means of the cupel and fur- 
nace, when it cannot be separated on the spot by the 
blow-pipe. These methods are taught in any book 
upon the assay of gold. 

Geology of Gold. Native gold is found, when 
in situ, with comparatively small exceptions, in the 
quartz veins that intersect metamorphic rocks, and 
to some extent in the wall-rock of these veins. The 
metamorphic rocks thus intersected are mostly 
chloritic, talcose and argillaceous schists of dull 
green, dark grey, and other colors ; also much less 
commonly mica and hornblende schist, gneiss, 
diorite, porphyry, and still more rarely granite. A 
laminated quartzite called itacolumite is common in 
many gold regions, and sometimes specular schists 
or slaty rocks, containing much foliated specular 
iron (hematite) or magnatite in grains. 

The gold occurs in the quartz in strings, scales, 
plates, and in masses which are sometimes an 
agglomeration of crystals. The scales are often 
invisible to the naked eye, massive quartz that 
apparently contains no gold frequently yielding a 
considerable percentage to the assay er. It is always 
very irregularly distributed, and never in con- 
tinuous pure bands of metal like many metallic 
ores. It occurs both disseminated through the 
mass of the quartz and in its cavities. 

In studying the geological aspects of this subject 
and making the practical application of our knowl- 
edge to the search, it may be stated that the 
original position of gold must have been in great 

126 prospector's field-book and guide. 

depths. From these depths it has been brought up 
by the upheaval of the granitic rocks and perhaps, 
along with basaltic and other intrusions shot up 
from immense depths. In the course of ages the 
attrition and breaking down of these higher or up- 
lifted levels, and the long-continued floods, rains 
and the waves of ancient oceans and other disinte- 
grating forces which produced the sedimentary 
rocks, at the same time liberated the gold which 
was incapable of decomposition. The gold thus 
found new and varied resting places in the sedi- 
mentary rocks of various ages, and in all the condi- 
tions which the surface might assume. 

The quartz rocks are neither igneous nor sedimen- 
tary, but are supposed to have been in liquid form 
as solutions of silex, which, during long periods of 
time, graduaily deposited the silex and whatever 
they contained, the water disappearing by evapora- 
tion or absorption. 

Frequently, cellular quartz has been found with 
gold within the cells, the material which surrounded 
the gold having become decomposed, and, thus 
releasing the undecomposed gold, the latter is found 
in the cells of the quartz. 

Gold, therefore, is to be expected and looked for 
in granitic regions (Fig. 46), and in those rocks and 
from those gravels and sands which owe their origin 
to such regions. It requires much judgment, gen- 
eral exploration, and knowledge of the region before 
the prospector can, with probability, expect to meet 
with gold, or before he should begin the search. 

GOLD. 127 

But with a full knowledge of the geologic condition 
of the country, and acting in accordance with the 
above facts, the prospector will soon come upon 
traces of gold, if any exist. 

In looking for indications, the prospector should 
never pass an ironstone " blow-out" without ex- 
amination, as, according to the German aphorism, 
" the iron hat covers the golden head," or as the 

Fig. 46. 

Section showing the two conditions under which gold is usually found in rock and 

The Structure of the Ural Mountains.— a. Granitic and gneiss rocks 
penetrated with greenstones and porphyrytic rocks containing gold finely 
disseminated, b. Micaceous, talcose, and argillaceous slaty rocks, snpposed 
to be Laurentian and Cambrian, c. Silurian and Devonian strata, d. Car- 
boniferous, limestone and grits, e. Coal measures. /. Permian and newer 
rocks. O, G, O G. Drift, filling hollows in rocks with gold, especially at the 
base of the drift. 

Cornishman puts it, " iron rides a good horse." 
The ironstone outcrop may cover a gold, silver, 
copper or tin lode. 

Besides the general instructions given above, con- 
siderable study should be devoted to the peculiar 
and seemingly irregular deposits of gold where it 
does not appear to have been washed down from any 
higher levels. For instance, in California and some 

128 prospector's field-book and guide. 

other districts free gold has been found in drifts and 
sand and in the beds of streams which have not 
only been filled up, but have been buried under 
regions of sandstone or other rocks, but the whole 
country has apparently been raised, or the sur- 
rounding region has sunk so as not to show any 
very considerable elevation beyond where the gold 
deposits have been formed. But, even in this case, 
the general rule has been shown to be correct, for 
these deposits have been proved to be in the beds 
or channels of ancient rivers, which had either been 
dried up and overflowed by vast eruptions of lava 
or basalt, and again by floods bringing new soil and 
creating sedimentary rock, or the country has been 
raised, or subsidence of a great extent of land has 
taken place. In many cases, however, no sub- 
sidence has occurred, but only overflow and filling 
up through ages, and the actual sources still remain 

Such events as we have just described do not 
transpire without leaving in some parts, traces or 
features or material, which, to the practiced eye 
of a skillful prospector, are evidences of some such 
movements and changes, and he may proceed to 
make a successful opening only after he has care- 
fully examined a large tract of country, for it is 
from extended survey that he may the more wisely 
judge of the relation of superficial parts to the 
greater depths of even small areas. 

Those rocks which lie more immediately over the 
granite, and which, although they owe their origin 

GOLD. 129 

to a sedimentary condition, have been subjected to 
heat and heated waters, as is supposed, we have 
called " metamorphic rocks." But they have been, 
probably, first formed from the disintegration of the 
most ancient rocks, and have brought with them 
fragments of gold. These metamorphic rocks have 
been changed from ordinary sedimentary rock by 
the action of heat and by pressure, and the influence 
of such treatment may be suspected by their appear- 
ance being crystalline in their composition ; that 
is, the fine grains which compose them, as well as 
the larger grains, are angular, whereas the materials 
of purely sedimentary rocks are fine without angular 
shape. The larger part of granite is supposed to 
have been metamorphic or changed, as the word 
means, or " altered " merely by the action of heat 
into a crystalline form or mass. 

The igneous rocks are those whose forms are due 
to having been melted and driven to the surface 
through fissures in the overlying rocks. They are 
variously composed of feldspar, hornblende, a little 
quartz, with comparatively small proportions of 
other substances, and are called by various names 
according to the composition. The metamorphic 
granite contains quartz, feldspar, and mica; the 
igneous granite contains little or no quartz. Syenite- 
granite contains hornblende in place of mica. Some- 
times the mica is very black, as hornblende is, and 
in that case may be distinguished from the latter 
by its more easy cleavage, as we have shown, under 
a sharp pen-knife ; this black mica is the kind we 

130 prospector's field-book and guide. 

have described as biotite (p. 31). There is a syenite 
which contains no quartz, called hyposyenite. These 
rocks are not the original home of gold, but at pres- 
ent it is very largely in these metamorphic rocks 
that the most paying gold is to be found, more 
especially in the quartz veins which have intersected 
these rocks. One, therefore, of the most important 
studies of the prospector is to acquaint himself 
familiarly with the appearance, the locations, and 
the departures of these metamorphic rocks. In 
many places where the alluvial gold, derived from 
the gold-bearing gravels, has almost ceased to be 
worth working, there still remain sources undis- 
covered, and these sources may probably be traced 
back even yet to some out-crop or to some ancient 
elevation now having subsided. 

The above remarks are applicable to explorations 
for other metallic ores than gold. They apply to 
silver, and especially to tin ores, and with some 
modifications, to copper ores and to quicksilver, as 
we shall show. 

Gold in combination. We have been speaking 
of gold as native and alone. But it must not be 
thought that this condition is the only one in which 
paying gold is found. The combinations of gold 
with various oxides and sulphides of other metals 
are very valuable, and should be studied. 

In almost all gold-bearing regions the iron sul- 
phides carry much gold, and in some regions the 
paying gold is found only in this substance. Hence, 
it is well for the prospector to determine the pres- 

GOLD. 131 

ence of gold in the pyrite or whatever sulphide may 
present itself. We, therefore, state a method or 
two of determining the fact that gold' exists in this 

1. To separate gold in metallic sulphides, for in- 
stance, iron pyrites. Powder the sulphide as finely 
as possible. Put about an ounce into a Hessian 
crucible and heat to a very low red heat for an 
hour, or until there is very little escape of sulphur 
fumes. Remove the crucible and put its contents 
into a porcelain dish. Pour over the roasted pow- 
der three fluidounces of strong nitric acid, by drops, 
until all violent action ceases. Add water, 8 or 10 
fluidounces ; the gold, if any, will appear as a very 
fine black powder ; filter and dry, pick out a small 
particle of the powder and mash it upon a hard 
surface, iron or agate, in an agate mortar ; if it is 
gold, it will show the gold color. A sufficient 
quantity of the dried powder may be placed upon 
a piece of charcoal, and by means of either or I 
flame of the blow-pipe it may be melted, and both 
by its color and softness be proved to be gold. 

There is a difficulty in this process which the 
prospector may not be able easily to overcome, and 
that is the necessity of using the strongest nitric acid. 
If he has a little laboratory he may readily make 
his own nitric acid of sufficient power, and then he 
possesses the simplest and quickest method of treat- 
ing sulphides or any gold-bearing pyrites. The 
process is as follows : This acid may be made from 
common saltpetre and sulphuric acid of commerce, 

132 prospector's field-book and guide. 

Dry the saltpetre after breaking it into small lumps 
of a half inch in diameter, carefully drop the lumps 
into a glass retort, hang the retort on a wire or 
stand, and introduce the beak into a glass bottle. 
Place the bottle in a basin of cold water and you 
may now apply the heat of a lamp, keeping the 
flame low and five or six inches off from the bottom 
of the retort. A coal-oil lamp with a short chimney 
may be used, and the heat regulated to a point at 
which brownish vapors appear in the retort. Keep 
enough acid in the retort to barely cover the salt- 
petre, and keep cool water in the basin, and the 
vapors come over and condense without much 

Stop the operation when the vapors cease to come 
over, and the mass in the retort seems to settle down 
to an even surface. Then draw out the beak of the 
retort and put the glass stopper into the bottle, and 
keep the bottle away from light and heat. Wash 
out the retort, and if you require more nitric acid, 
renew the operation. The retort should be tubu- 
lated to allow of adding sulphuric acid during the 
operation if needed. 

This acid is a yellowish-brown liquid and is 
known as " fuming nitric acid," and is one of those 
very active and convenient aids in the laboratory 
which cannot readily be purchased, and, therefore, 
must generally be made ; but so little of it may be 
used that a small quantity goes a great way, and it 
will effect a result which the strongest and purest 
chemically-pure nitric acid fails to produce. Its 

GOLD. 133 

effect is to release the gold from the combination of 
iron and sulphur by oxidizing the latter as well as 
the former, and rendering them soluble in water, 
while the gold remains in metallic form of an ex- 
ceedingly fine black powder, as has been said. 

2. Another method of detecting and separating 
the gold, where the above one cannot be used, is 
by pulverizing the sulphide ore very finely and mix- 
ing it with three or four times its weight of caustic 
potash or caustic soda, and then subjecting the 
crucible, which contains the mixture, to a low red 
heat till all the contents cease agitation and become 
perfectly tranquil. Then remove the crucible, wait 
till all is cool, and then add hydrochloric (muriatic) 
acid in an amount equal to three or four times the 
bulk of the mass. To this, after standing three or 
four hours in a warm place, add the usual nitric 
acid (about an ounce), after transferring all the 
liquid to a porcelain dish, or, next best, to a beaker- 
glass. Let it stand in a warm place for about an 
hour, then add a little more nitric acid (about half an 
ounce), stir it well with a glass rod or strip of glass, 
and let it stand again for an hour or two. Examine 
carefully, and if it seems to have been dissolved 
more thoroughly than before, add a little more 
nitric acid and warm again, stirring well as before. 
If no more seems to be dissolved, then filter and 
wash the sediment in the filter and let it dry, and 
remove the filter and contents for further examina- 
tion. Now precipitate the gold from the filtrate by 
pouring into it a solution of ferrous sulphate. [Any 


clear green crystals of " copperas " (sulphate of iron) 
of the drug store, filtered, after saturated solution 
in clean rain-water and kept in corked bottles, will 
answer this purpose.] Let the solution stand in a 
warm place for an hour, drop in a few more drops, 
and if any further precipitation takes place, add 
half an ounce of the sulphate, stir it again, let it 
remain an hour longer in a warm place till all pre- 
cipitation ceases. Decant the supernatant clear 
water and transfer the remainder to a filter-paper 
carefully, and a little at a time, to avoid breaking 
the filter-paper, then rinse the porcelain dish to get 
all particles upon the filter-paper, and when all the 
liquid has passed through, let it dry, and remove 
all the contents of the paper to a small porcelain 
capsule or crucible, and apply the heat of the blow- 
pipe to burn off the paper or any organic substance 
which may have got into the powder ; the gold 
remains, which may be gathered upon charcoal and 
melted into a globule by the concentrated flame of 
the blow-pipe, if in small quantity. Lastly, ex- 
amine the contents of the filter which was laid 
aside ; and, if any appearance of gold is noted, 
separate it under examination by a pocket lens. 

The high value of gold renders even a grain of 
gold to the pound of ore, if that pound is an aver- 
age pound in the ton, worth $80 to the ton of 2000 
pounds. Hence, a pyrites which contains a half 
grain to the half pound may prove too valuable to 
neglect. In the Brazils, in deep mines, the ore 
yields only half an ounce to the ton of ore, and yet 

GOLD. 135 

it is mined at a profit.* In California, a continuous 
yield of three-eighths to half an ounce of gold to the 
ton of quartz is considered profitable working.! 

It must be remembered, however, that the above 
process of extracting the gold from a pyritous ore 
does not extract with perfect accuracy all the gold 
unless conducted with more care and time than we 
have suggested, but it is sufficient to reveal the fact 
that the ore is valuable. 

3. The following method requires more time and 
care and the use of a little furnace, but will give 
very accurate results. Pulverize the ore supposed 
to contain any gold, whether pyrites or not. Heat 
it in a crucible very gradually at first, increasing 
the heat to drive off as much sulphur as possible, 
frequently stirring it and increasing the heat till 
all fumes seem to have escaped. Withdraw it and 
prepare a crucible (clay or Hessian crucible), by 
dipping it in a strong solution of borax in water, 
and heating the crucible and repeating the dipping 
and heating till the crucible shows a glazed inside. 
Then transfer all the roasted powdered ore, after 
weighing it (if you desire relative quantity), into 
the crucible, and cover it with the following mixture 
(called a flux) : Six times the weight of ore of lith- 
arge, one of dry borax, and about twenty grains of 
charcoal pulverized. Heat slowly at first, not al- 
lowing much foaming, until all is quiet and the 

*Makins' Metallurgy, p. 227. 

t Da vies' Metalliferous Minerals and Mining, p. 64. 

136 prospector's field-book and guide. 

metal button settles down at the bottom of the cru- 
cible. Cool and break the crucible to extract the 
button of metal, which is now ready for cupelling. 
{For this process see p. 98.) 

Any one of these three methods of separating all 
the usual ores may readily be employed, and a little 
practice will enable the operator to be expert in 
their use. A great deal more depends upon the 
skill of the operator than upon the cost of his 

It has not been thought necessary to give a list of 
places in the world where gold has been found, but 
in view of the excitement created by the rich finds of 
gold, in July, 1897, in the Klondike district, Alaska, 
it may be of interest here to give a brief description 
of the Yukon gold district, which besides the Klon- 
dike, comprises the Hootalinqua, Stewart, MacMil- 
lan, Forty-Mile, Sixty-Mile, Birch Creek, Munook 
Creek, Tanana and Koyukuk districts. 

Throughout nearly the whole of Alaska gold is 
found disseminated in the detritus which has been 
derived from the abrasion of the solid rocks. Often 
it is in such small amounts that it cannot be pro- 
fitably extracted, but sometimes it is concentrated 
by water action in such a degree as to invite min- 
ing. Thus far the profitable deposits have all been 
found in or near the beds of the present streams. 
These recent gravels may be divided into two chief 
classes. In the larger streams accumulations of 
gravel are made in places of slackening current? 
such as the inner or concave sides of curves. These 

GOLD. 137 

accumulations are called bars, and often contain 
much gold. The other occurrence is in the small 
gulches which feed the larger streams. In the bot- 
tom of the gulches the gravels are frequently very 
rich in gold, and as these are easily worked, they 
constitute at the present time the most important 
class of placer deposits. 

The gold of the Yukon district is chiefly derived 
from quartz veins, which are found most abund- 
antly in the schists of the Forty-Mile and the Birch 
Creek series, although not infrequently in the igne- 
ous and pyroclastic rocks of the Rampart series. It 
is also derived, although to a far less extent, from 
impregnated shear zones, which occur especially in 
the Rampart series. Of the quartz veins one set is 
sheared and one unsheared. The first is difficult to 
follow, for the veins are broken and non-persistent. 
The veins of the second set are often persistent and 
wide, and in some cases may be mined profitably. 
Impregnations along shear zones may also in some 
cases be sufficiently rich in metallic minerals to 
form ores under favorable conditions ; and the rock 
in the region of these shear zones is often unfaulted, 
so that these ore bodies may be expected to be com- 
paratively persistent. 

The quartz veins are connected with dikes, chiefly 
light-colored crystalline rocks such as granite and 
aplite. This should be kept in mind in prospecting, 
and auriferous veins may be looked for in the schists 
near the dikes. In some cases, although not so 
commonly, they may also occur at some distance 
from a dike. 

138 prospector's field-book and guide. 

These gold-bearing rocks form a definite belt, 
extending in a general way from the lower Ram- 
parts of the Yukon and below to Dease Lake and 
other mining districts in British Columbia, a dis- 
tance in a straight line of about a thousand miles. 
Of this distance, 400 or 500 miles is in American 
territory. The width of the belt varies chiefly with 
the minor folding, v/hich has accompanied the 
greater plications. In this belt not only the gold- 
bearing veins, but the richest placers are found. 
This is naturally the case, since the gold in these 
placers is worn out of the solid rocks. It is espec- 
ially true that the rich gulch gravels are in this 
belt, and also the most paying bar gravels, although 
fine gold in some cases may be carried somewhat 
outside the belt, and may be sufficiently concen- 
trated in favorable situations to pay for washing. 

The Birch Creek, the Forty Mile and the Klon- 
dike districts are all in this belt, and are all in the 
schistose rocks, and in these rocks new deposits 
of value may be looked for. Some placer diggings 
of value may also be found in the rocks of the 
Rampart series, but as a rule higher horizons are 
.probably barren, save in exceptional cases. Con- 
glomerate made up of the detritus from the schis- 
tose Birch Creek and Forty Mile rocks should be 
prospected, however, since they may prove to be 
fossil placers. Ancient gravels lying above the 
present stream channels should also be kept in 
mind, for they may in places contain sufficient gold 
to be profitably mined. 

GOLD. 139 

Rule for ascertaining the amount of gold in a lump 
of auriferous quartz, according to Phillips : 

The specific gravity of gold is 19.000. 

The specific gravity of quartz is 2.600. 

These numbers are given here merely for conven- 
ience in explaining the rule ; they do not accurately 
represent the specific gravities of all quartz and 
quartz gold. (The quartz gold of California has 
not, on an average, a specific gravity of more than 

1. Ascertain the specific gravity of the lump. 
Suppose it to be 8.067. 

2. Deduct the specific gravity of the lump from 
the specific gravity of the gold ; the difference is 
the ratio of the quartz by volume : 19.000 — 8.067 
= 10.933. 

3. Deduct the specific gravity of the quartz from 
the specific gravity of the lump ; the difference is 
the ratio of the gold by volume : 8.067—2.600 = 

4. Add these ratios together and proceed by the 
rule of proportion. The product is the percentage 
of gold by bulk : 10.933 + 5.467 = 16.400. Then, 
as 16.400 is to 5.467, so is 100 to 33.35. 

5. Multiply the percentage of gold in bulk by its 
specific gravity. The product is the ratio of the 
gold in the lump by weight : 33.35 x 19.00 = 

6. Multiply the percentage of quartz by bulk 
(which must be 66.65, since that of gold is 33.35) 
by its specific gravity. The product is the ratio 

140 prospector's field-book and guide. 

of the quartz in the lump by weight : 66.65 x 2.60 
= 173.29. 

7. To find the percentage, add these two ratios 
together and proceed by the rule of proportion : 
633.65 + 173.29 = 806.94. Then as 806.94 is to 
633.65, so is 100 to 78.53. Hence, a lump of aurif- 
erous quartz having a specific gravity of 8.067, con- 
tains 78.53 per cent, of gold by weight. (The 
Mines, Miners, and Mining Interests of the United 
States in 1882, by Win. Ralston Balch, Phila., p. 



Tellurium Minerals. Tellurium is the only 
metal which has hitherto been found in nature in 
actual chemical combination with gold. It also 
occurs in a native state, and, combined with other 
metals, forming tellurides. The tellurides com- 
prise a small but interesting group, and occur under 
similar conditions of association in a few widely 
separated localities, the more abundant ores being 
of great economic value, as containing a large pro- 
portion of gold and silver. The most important of 
these are given below, but tellurides of mercury, 
bismuth, lead, and nickel also exist. 

lellurium has a bright tin-white color and a 
metallic lustre. It is brittle and very fusible, vola- 
tilizing almost entirely and tinging the blow-pipe 
flame green. White coating on charcoal. Soluble 
in nitric acid. Rare. 

Nagyagite, foliated or black tellurium. Streak, 
blackish lead-gray. Color, blackish lead-gray. 
Lustre, metallic. Sectile, flexible in thin lamina?. 
Occurs in granular or foliated masses. If the 
mineral is treated for sometime in the 0. F. a 
malleable globule of gold remains. This cupelled 
with a little assay lead assumes a pure yellow color. 

142 prospector's field-book and guide. 

Nagyagite forms a valuable gold ore in Nagyag, 

Hessite. Streak, iron black. Color, lead to steel 
gray. Lustre, metallic. Sectile, brittle. Forms 
cubic masses of fine-grained texture. Before the 
blow-pipe fuses on charcoal to a black globule ; this 
heated in R. F. presents on cooling white dendritic 
prints of silver on its surface ; with soda is reduced 
to a globule of silver. 

Petzite. Color, steel gray, iron black, sometimes 
peacock tarnish. Lustre, metallic. Sectile, brittle. 
Forms cubic masses of fiue-grained texture, like 
hessite, which it resembles in most physical char- 
acters, but is much denser. In one locality in 
Colorado it forms one of the principal minerals in a 
group of quartz veins in porphyries traversing very 
coarse granites, and occurs in rounded masses, 
sometimes implanted on iron pyrites and irregular 
crystalline aggregates, which are occasionally coated 
with encrusting pseudomorphs of gold. Some 
varieties giving 18 per cent, of gold have a specific 
gravity of 8 to 8.3 ; others giving 24 to 26 per cent, 
of gold have a specific gravity of 9 to 9.4. 

Sylvanite or graphic tellurium. Streak, steel gray 
to silver white. Color, steel gray to silver white, 
and sometimes nearly brass yellow. Lustre, metal- 
lic. Sectile, brittle in thin laminse. Colors the 
flame blue or bluish green, giving a white incrusta- 
tion and a dark gray bead which can be reduced 
alone after long blowing, or more quickly with 
soda, to a yellow malleable, metallic bead of silvery 


gold. The proportion of gold to silver varies. In 
California sylvanite occurs in narrow veins travers- 
ing porphyry. It is called graphic because of the 
resemblance in the arrangement of the crystals to 
writing characters. 

Tellurides constitute exceedingly valuable ores 
when they are sufficiently rich to allow of hand 
picking and sale to smelters, and even the poorer 
ores can be treated by roasting and either chlorina- 
tion or cyanidation. In many cases attempts to 
concentrate have been unsatisfactory, as the mineral 
frequently slimes a great deal ; but concentration is 
said to have been successfully applied in Boulder 
County, Colorado, and the possibility depends to a 
great extent upon the nature of the ore. Specimens 
are found .in many localities, but it is in compara- 
tively few places that workable deposits exist. 

Platinum occurs native and in flattened or 
angular grains or nuggets which are malleable. 
Its color and streak are steel-gray, Lustre metallic 
bright. Isometric, but is seldom found in crystals. 
Hardness 4 to 4.5. Specific gravity 16 to 19. As 
heavy as gold, and, therefore, easily distinguished 
and separated from lighter materials. Before the 
blow-pipe it is infusible ; not affected by borax, ex- 
cept when containing some metal, as iron or copper, 
which gives the reaction. Soluble only in heated 
nitro-muriatic acid. 

Platinum is occasionally found in the gold-bear- 
ing gravels of California and Oregon, but the an- 
nual production is small. There are no means of 


knowing whether it is present in sufficient abund- 
ance for separate mining. The prospectors, as a 
rule, do not know the value of the black sand, nor 
are they always able to distinguish it from less val- 
uable ores ; and it is, therefore, not unlikely that 
deposits may yet be found. 

The supply of platinum comes chiefly from 
Russia, where it occurs in gravels, probably origin- 
ally auriferous, on the Siberian side of the Ural. 
Since serpentine is usually near at hand, and the 
placers increase in richness as the rock is ap- 
proached, and since the metal has been found in 
this rock, it seems probable that this is the source. 
This mode of occurrence of platinum and the asso- 
ciation with serpentiferous rocks prevails also in 
other platinum-producing regions. Platinum is 
always alloyed with the other metals of the plat- 
inum group, iridium, osmium, palladium, etc., and 
with iron, the amount of platinum varying from 
50 to 80 per cent. In Russia, as well as in other 
platinum-producing regions, chrome iron and irid- 
osmium are associated with the metal. The United 
States now consumes more platinum than any other 
country, incandescent electric lamps and other elec- 
tric apparatus calling for a great supply. Although 
only a very minute quantity is required in each 
case, so many lamps are called for that the demand 
is very great, and the price has risen much higher 
than formerly. It may be interesting to note that 
the name platinum is derived from plata, the Span- 
ish word for silver, since it was regarded in South 


America at the time of its discovery (1735) as an 
impure ore of that metal. 

Platinum, like gold, does not readily combine 
with other metals, and in nature the only com- 
pound known is an arsenide called Sperrylite, which 
is found in very small quantities in the Sudbury 
section of Ontario, Canada. Its color is tin-white ; 
lustre bright ; hardness about 7 ; specific gravity 

Platinum may be distinguished by its great 
weight, by its gray color, its sectile nature, and by 
the fact that it will not dissolve in any simple acid, 
and with difficulty in nitro-muriatic acid (aqua- 
regia). It may be distinguished from lead by its 
action under the blow-pipe flame, since lead melts 
immediately, leaving a yellowish coating, while 
platinum refuses to melt under the hottest flame, 
and leaves no coating whatever. When it exists in 
the alluvial soil it may be "panned out" just as 
gold or other heavy metals, and even more easily 
because of its greater gravity. 

It may be found in some metal-bearing veins in 
crystalline metamorphic and syenite rock, from 
which it has been washed down just as in the case 
of gold. In the latter condition it has been found 
more extensively than in any other. 

Its chemical test is as follows : Dissolve the 
grains of the ore in nitro-muriatic acid (4 parts 
muriatic acid to 1 part nitric), preferably with 
gentle heat, add proto-chloride of tin (solution) also 
called stannous chloride (SnCl ? ) ; if platinum is 


present a dark brownish-red color will be produced, 
but no precipitate. 

The metal may be obtained separate from its gold, 
and in the presence of many other metals, by evap- 
orating the above solution of the ore in a porcelain 
dish to dryness, at a gentle heat with ammonium 
chloride (sal ammoniac or muriate of ammonia), 
and the residue treated with dilute alcohol (one- 
fourth part water). The gold will remain in solu- 
tion and the platinum be precipitated, the precipi- 
tate to be ignited, when the platinum will be pure. 
The gold, if present, may be precipitated by adding 
a solution of ferrous sulphate, after evaporating off 
the alcohol. Ferrous sulphate is proto-sulphate of 
iron (copperas in crytals). 

Stannous chloride may readily be purchased at 
any chemist's warehouse, but as it is easily pre- 
pared we give the best method as follows: File a 
piece of tin into powder aud heat very hot (nearly 
to boiling) with strong hydrochloric acid in a porce- 
lain dish or beaker-glass, always keeping tin in the 
glass or dish, by adding tin if necessary. When no 
hydrogen gas is evolved (*. e., no bubbles arise), 
dilute with four times its bulk of pure water, 
slightly acidulated with hydrochloric (muriatic) 
acid, and filter. Keep the filtrate in a well-stop- 
pered bottle in which some tin has been placed. If 
you have pure tin-foil, that form of tin may be used, 
for without the presence of metallic tin the stannous 
chloride (SnCl 2 ) is in danger of changing into stan- 
nic chloride (SnCl 4 ) with precipitation of a white 


substance (oxy chloride of tin), which renders the 
reagent unfit for use. 

Iridium, a steel-white, extremely hard metal, 
next in specific gravity to osmium, is supplied 
partly from its alloy with native platinum, and 
partly from the iridosmium which occurs in the 
platiniferous gravels. It is used for pen-points and 
in jewelry, and recently in metal-plating. 

Osmium is the heaviest known metal. It comes 
from the same sources as iridium, and in the form 
of iridosmium is used for pointing tools and pens. 

Palladium is a brilliant, silver-white metal. It 
also occurs with platinum, but on account of its 
high price is but little used. 

Silver. This metal occurs native in various 
shapes, as in small grains in the rock, as branching 
and leaf-like, and also in small octahedral crystals 
and in other forms. Hardness, 2.3 to 3 ; specific 
gravity, 10.1 to 11.1, according to its purity. It is 
never found absolutely pure, but contains some 
gold and frequently a little copper. 

It is always sectile and malleable, and in this 
respect very easily distinguished from a substance 
frequently mistaken for native silver, namely, mis- 
pickel, which is an arsenide of iron, having very 
much the appearance of silver, but always brittle. 

Before the Blow-pipe, on charcoal, native sil- 
ver is distinguished from tin, zinc, antimony, or 
bismuth, by the fact that it melts and leaves no 
whiteness or any other appearance of oxide upon 
the coal around the globule. 


Tin will leave a white film, and lead a yellow ; 
zinc a yellow which whitens on cooling. But silver 
leaves no film or cloud of any kind upon the coal. 

The Chemical Test of silver is as follows : Dis- 
solve the metal in nitric acid in a test-tube, prefer- 
ably with the heat of an alcohol flame, but not to 
the boiling point. Add an equal amount of pure 
water (clear rain water will answer), then drop in 
several drops of a solution of common table salt or 
muriatic acid. If a cloudy white precipitate occurs 
which settles and blackens after exposure of a few 
seconds to sunlight or a few minutes to daylight, 
the substance is silver. 

It should be remembered at this point that this 
test is for silver alone, since lead and mercury are 
also precipitated as a white cloud by the same solu- 
tion, but neither blackens by exposure to the light. 
This distinguishes silver. If, however, further 
proof is needed, drop into the test tube strong 
ammonia water ; the precipitate is dissolved if it is 
that of silver ; it is not if it be of lead, and it is 
blackened by the ammonia if it is mercury. 

If there is much copper in the silver it may be 
detected by dipping a clean strip of polished iron 
or steel into the solution, for the metallic copper 
will immediately appear upon the surface of the 

It must not always be supposed that native silver 
is metallic or white in appearance, for it is readily 
tarnished by sulphur, and the proximity of sulphur 
in other minerals or in water may greatly discolor 
the native silver. 


Comparatively speaking, very little of the silver 
of the mines is derived from native silver. Most 
of the silver of commerce is obtained from some 
of the minerals named below, which are combina- 
tions of silver with other metals, and with sulphur 
or chlorine, as sulphides of silver, etc., in which 
condition they bear no resemblance to native silver. 

But in all silver minerals of any commercial 
value, the already mentioned tests are usually suffi- 
cient to detect the existence of silver. 

Other forms in which silver is found are — 

Silver Sulphides are very largely associated 
with lead sulphides or galena, and sometimes called, 
when pure, 

Silver Glance or Argentite. This is found in 
masses, but when crystallized it occurs in cubes or 
octahedral forms. When freshly broken it has 
a metallic lustre, otherwise it is of a dull gray or 
leaden appearance. It is sectile, and its " streak " 
or the color of its powder is the same as that of the 
mineral itself, and rather shining. Chemical com- 
position : silver 87 ; sulphur 13. Hardness 2 to 
2.5. Specific gravity 7.1 to 7.4. 

The ore is soluble in nitric acid, and on adding 
common salt to the solution, a white curd is thrown 
down which blackens on exposure to sunlight. It 
is very fusible, giving off an odor of sulphur when 
heated. Before the blow-pipe on charcoal, with or 
without carbonate of soda, it yields a white globule 
of metallic silver which can be flattened under a 

150 prospector's field-book and guide. 

The ore in an amorphous state is most common 
in earthy vein-stuff (called metal azul) or with 
pyritic minerals, especially galena. It is rarely 
recognizable by form or physical character, as rich 
quartz only differs from ordinary by its pale bluish- 
gray tint, and argentiferous galena is, as a rule, 
undistinguishable by sight from that containing no 

Ceragyrite or horn silver. The mineral 
known under this name is a chloride of silver oc- 
curring in veins of clay slate with other ores of 
silver, usually only in the higher parts of these 
veins. With ochreous brown iron ore with several 
copper ores, etc. Lustre, waxy, resinous. It yields 
a shining streak. It is translucent on the extreme 
edges and has a waxy appearance. It cuts like 
horn or wax, and on an outcrop looks like dirty 
cement. It contains 75.3 per cent, silver, and 24.7 
per cent, chlorine when unmixed or nearly pure, 
and then has a pearly-gray or greenish-gray appear- 

A polished piece of iron may be slightly coated 
with silver if a piece of horn silver is moistened and 
rubbed upon the iron. 

Horn silver is very easily fusible, it melting in 
the flame of a candle. Heated with carbonate 
of soda on charcoal, it yields a globule of metallic 

This mineral, in various degrees of impurity, 
forms a very large part of the silver-bearing ores 
of some mines in South America, as well as in the 


Western States and Territories of the United States. 
It is a valuable ore. 

Stephanite or Brittle Silver Ore is a silver 
sulphide with antimony, and is found in masses and 
sometimes in rhombic prism crystals in veins with 
other silver ores. It is easily distinguished from 
silver sulphide (or glance) by the fact that it is 
brittle, while the glance, if fairly pure, may be cut 
with a knife in chips without breaking. 

This ore is black or iron gray, has a hardness of 2 
to 2.5 and a specific gravity of 6.2 to 6.3, and when 
pure, contains 71 per cent, of silver, the rest being 
antimony with some other admixtures, usually iron 
or copper. It is an abundant silver ore in the 
Comstook Lode, Nevada (Figs. 47, 48), in the Reese 
River and Humboldt and other regions, and at the 
silver mines in Idaho. 

On charcoal, under the blow-pipe, it decrepitates 
and coats the coal with a film of antimony (anti- 
monous acid), which, after considerable blowing, 
turns red, and a globule of silver is obtained. 

Red Silver Ore, or Ruby Silver, is an ore 
which contains arsenic and antimony, or more usu- 
ally arsenic or antimony. That containing only 
antimony is dark red and is known mineralog- 
ically as Pyrargyrite ; it contains 59.8 per cent, 
silver, 17.7 per cent, sulphur, and 22.5 per cent, of 
antimony. It occurs generally in crystals. When 
the silver sulphide is associated with arsenic only, 
the color is light red and the name Proustite is 
applied to it. It contains 65.5 per cent, of silver. 

152 prospector's field-book and guide. 

It may contain both arsenic and antimony, and 
have a grayish appearance. In Idaho, it has been 
found in masses of several hundred pounds weight, 
at Poorman Lode (Dana). In Mexico it is worked 
extensively as an ore of silver. 

Bromic Silver or Bromyrite. This is a com- 
mon ore containing bromine 42.6 per cent, and 
silver 57.4 per cent. 

There are other minerals in which silver occurs, 
but they are only exceptions or rare, and if one is 
acquainted with those mentioned above, he will 
very likely detect the rarer silver minerals, which 
are not ores in the usual sense, but they may lead 
when discovered to valuable results. 

Valuing silver ores. A simple, but rough, method 
is sometimes adopted of testing the value of ores 
from day to day when chlorides are the minerals 
chiefly worked, by powdering the ore in the mine, 
mixing it with a solution of hyposulphite of lime 
which dissolves the chloride, and then adding 
sodium sulphide, which forms a dark-colored pre- 
cipitate if much silver is present. It is evidently 
impossible to estimate in this way the contents of 
silver, but it affords a very good test whether the 
ore is of value or not. 

Geology of Silver Ores. The most valuable 
ores occur in the earlier or more ancient rocks, such 
as the granitic or gneissoid rocks, clay slates, mica 
schists, older limestones, and in the metamorphic 
rocks. The remarkable geologic conditions under 
which silver ores and veins occur may be under- 


stood more readily by the following diagrams than 
by any descriptions without them. (Figs. 47 and 

In the diagrams the rocks are seen tilted up from 
the horizontal position to one nearly vertical, but 
evidently after this uplifting the trachytic dykes 
were shot through the masses of conglomerate. 
The lodes bearing silver are represented by contin- 
uous double lines, and the dykes by dotted vertical 
lines. The entire distance represented from Sutro 
to the west end of the diagram is about 5J miles, 
on a course east and west, being the same as that of 
the Sutro tunnel upon this branch, which joins or 
intersects to the north and south branch of the 
tunnel at the Comstock lode. 

In order that the superficial nature of the country 
may be understood, we have given the north and 
south section of the same region, showing some of 
the mines by vertical black lines and by shaded 
spaces where the mines have been worked more or 
less extensively. (Fig. 48.) 

The north and south section exhibits the hilly 
surface, and fully illustrates the work of the pros- 
pector who would become acquainted with the min- 
eral deposits of a similar region. 

It will be seen in the east and west section that 
all the lodes out-crop. (Fig. 47.) The non-metallic 
substances of these lodes are quartz, fluorspar, with, 
perhaps, some chlorides or sulphides ; the latter may 
be metallic, and there may occur some traces of 
gold and silver, perhaps also of antimony, lead, etc. 



o -e 


The wisest course, therefore, is for the prospector, 
after having settled in which direction the strike or 
course of the strata runs, to make an examination 
directly across the strata, the chief object being to 
learn the nature of the rocks of the region, and, at 
the same time, to detect the outcropping of any 
lodes or dykes. 

His object is to become acquainted with the strata 
by means of the loose material, the fragments, or 
small outcropping rocks, where he cannot penetrate 
beneath the soil. 

It may become necessary to traverse a great dis- 
tance before any certain information may be gained, 
and where the hill surfaces are covered with soil, the 
ravines will frequently disclose the nature of the rock. 

It will be noticed that the Comstock Lode begins 
immediately adjoining the syenite rock, and at the 
outcrop extends six or eight times the actual thick- 
ness of the lode below. It is also apparent that the 
lodes generally, at least in this region, bifurcate 
near the surface, even in the syenite, and when an 
outcrop has been discovered, the probability is that 
not far off another outcrop of the same lode may be 
found (Fig. 47). 

The Comstock Lode has been traced for four or 
five miles north and south, but the values of the 
deposits are not uniform. The great bodies of ore 
may be seen in the north and south section where 
the excavations are largest, as around the Savage, 
and from the Exchequer to the Crown Point prop- 
erties. But this whole region is filled with dykes 

156 prospector's field-book and guide. 


and lodes for miles beyond the Comstock Lode, 
which lies on the eastern slope of a range of hills 
running somewhat parallel, but about fifteen miles 
east of the great Sierra Nevada range, south of the 
Pacific Railroad, and between the lakes Bigler and 
Carson in the western part of the State. 

In the east of Nevada, at the Eureka Mines, the 
ores are found in a bed of limestone overlying the 
granites, quartzose slates, and metamorphic rocks 
of great thickness. The limestone containing the 
ore is about 300 feet thick. But while the imme- 
diate geology varies from that of the Comstock, the 
general facts are the same, namely, that the silver- 
bearing lodes are in or very near the granites or 
earliest rocks. In this case the overlying rocks, 
though limestone, are dolomitic, containing from 
36 to 46 per cent, of carbonate of magnesia, and the 
mineralized belt of limestone, or that containing 
the ores, is very much broken, and in some places 
apparently crushed, as if it had been subjected to a 
grinding process, and then partly rejoined by the 
cementing power of calcareous matter deposited 
from solution in percolating water. 

A peculiarity in this last described limestone is 
found in the large caverns which occur along the 
course of mineral deposit. On the floors of these 
caverns are found beds of ore which seem to have 
dropped from their position in the limestone, as 
that has been dissolved out and carried off where 
the fissures easily permitted the percolating waters 
to~pass rapidly away. 

158 prospector's field-book and guide. 

The geology of this region appears to be in the 
order of granites, quartzose slates and metamorphic 
rocks of great thickness, limestones containing 
segregations of ore, calcareous shales, and these 
surmounted by limestones also of great thickness. 
The special region to which this geological series 
refers is the Ruby Hill mines. 

The Emma Mine, with many others, is situated 
still further east, in the Wahsatch range of moun- 
tains, which runs north and south about twenty 
miles east of the Great Salt Lake. This mine is 
about the same distance southeast of the Great Salt 
Lake. The adjacent rocks of this mine are granite, 
in massive beds, dipping from 50° to 70° eastward. 
This is overlaid by quartzites of a reddish color, 
then occurs a series of slates, upon which are thick 
beds of white limestone, and these pass rapidly into 
the carboniferous dolomitic limestone. It is in this 
last limestone that the ore deposits of the Emma 
and adjacent mines are worked. 

It is a fact, however, that the ores are mainly 
composed of silica and lead, of which there is over 
70 per cent. The amount of silver is about 0.40 to 
0.50 of 1 per cent, according to some analyses. A 
sample amount of 82 tons, gross, yielded 156 ounces 
of silver. 

These three mining districts present the general 
geologic conditions in which the silver ores are 
found in these and other States and Territories, and 
the prospector should expect to find surface indica- 
tions accordingly, but modified more or less by ex- 
posure to weather. 


Although, from the preceding illustrations, silver 
is shown to be found both in the very early groups 
of rocks and in the carboniferous limestone, the 
latter is the exception, as it appears to be found 
there only when that limestone has occurred with 
little or no separating horizons from the earliest 


Copper occurs both native and in a compound 
state. Native copper is found in various forms, 
and even in octahedral crystals. Its color is copper 
red ; it is always sectile and malleable ; hardness 
2.5 to 3, specific gravity 8.5 to 8.9, according to 
purity. Frequently associated with native silver. 
It is tested by the blow-pipe ; giving in small quan- 
tities a blue tinge to almost black in the borax bead, 
according to quantity used, and the kind of flame, 
whether inner or R, or outer or 0, the latter giving 
blue color, the former giving the copper color or 
metallic opaque brown. 

Native copper dissolves readily in nitric acid, 
and if ammonia be added, the solution becomes 
green, or greenish-blue if ammonia be in excess. 

In the absence of any chemicals or a blow-pipe, 
the mineral, when containing native copper, or 
when only a compound containing copper, may be 
tested by heating it either in the mass, or, better, in 
powder, and when hot, dropping it into some salty 
grease and then putting it in a flame or upon burn- 
ing charcoal, when the characteristic green color 
will appear in the flame with great distinctness. 

COPPER. 161 

Moreover, if the mineral contains copper in con- 
siderable quantity and it is dissolved in nitric acid, 
the copper will be deposited immediately upon a 
strip of polished iron or upon the end of a knife 
blade, if either be dipped into the solution. 

The natural combinations of copper are almost 
endless. Not less than a hundred mineral species 
may be regarded as copper ores from the practical 
miner's point of view, i. e., possessing economic 
value, and there are probably as many more which 
are not yet utilized. As might be expected the 
range of chemical associations is equally wide, em- 
bracing sulphides, antimonides, arsenides, oxides, 
chlorides, bromides, iodides, carbonates, sulphates, 
phosphates, silicates, arseniates, simple and com- 
pound, hydrated and anhydrous, in almost every 
degree of variety. 

Below several of the more important ores of 
copper are mentioned, and also some copper min- 
erals which, to the prospector, will be suggestive 
that the more important ores are not far off. 

Cuprite, Red Copper Ore or Ruby Copper. 
Occurs massive, granular, and earthy. Streak, 
shades of brownish-red, shining. Brittle. Color, 
deep crimson, cherry-red ; opaque with very bril- 
liant reflection ; sometimes weathered to an iron- 
gray on the surface. Hardness, 3.5 to 4 ; specific 
gravity, 8. Composed of copper, 88.78 per cent., 
the remainder oxygen, when pure. 

Before the blow-pipe, on charcoal, it yields a 
globule of metallic copper ; with borax bead gives 


the indication of copper. Dissolves in hydrochloric 
acid, giving a brown solution which, when diluted 
with water, deposits white insoluble cupric chloride. 
In nitric acid it forms a blue solution. Sulphuric 
acid decomposes it into cupric oxide (CuO) and 
metallic copper, the former passing into solution as 
cupric sulphate, while the latter is undissolved. 

Cuprite occurs in granite and slate with copper 
ores and galena and forms a valuable source of the 
metal. The massive variety is known as tile ore ; 
brick ore is a mixture of copper and limonite. The 
fibrous variety is known as plush copper ore. 

Chalcocite, Copper Glance or Vitreous Cop- 
per. Massive ; slightly sectile. Color and streak, 
bluish-lead gray, brownish ; brilliant when fresh ; 
black and dull, on exposure to sunlight tarnishing 
to blue or iridescent. Hardness 2.5-3 ; specific 
gravity 5.5-5.8. Composed of copper 77.2; sul- 
phur 20.6, and sometimes, a little iron. It is 
fusible in a candle flame. 

Before the blow-pipe it gives off an odor of sul- 
phur. When heated on charcoal, a malleable 
globule of metallic copper remains, tarnished black, 
but rendered evident on flattening under a hammer. 
With borax bead it gives the indications of copper. 
Dissolves in nitric acid, forming a blue solution. 
These tests distinguish it from sulphide of silver. 
Occurs with other copper-ores. 

Tetrahedrite or Gray Copper Ore. Brittle ; 
steel-gray or iron-black, sometimes brownish ; hard- 
ness 3-4 ; specific gravity 4.75-5.1. Composed of 

COPPER. 163 

copper 38.6, sulphur 26.3, and frequently antimony 
and arsenic, zinc, iron, silver, etc. It frequently 
contains silver, and sometimes as much as 25 to 30 
per cent. 

Before the blow-pipe on charcoal it fuses, gives 
an incrustation of antimonious and sometimes 
arsenious acid, oxide of zinc and oxide of lead. 
Arsenic may be detected by its odor on heating 
incrustation in R. F. or fusing with soda. Oxide 
of zinc gives a green color when heated with nitrate 
of cobalt solution. The iron and copper in the resi- 
due are found either by fluxes (on platinum) or by 
reduction with soda. Silver is determined by cupel- 

Tetrahedrite is soluble in nitric acid, arsenious 
and antimonious acids separating. The solution 
becomes blue from copper by adding ammonia in 
excess, and cloudy with hydrochloric acid when 
silver is present. 

Tetrahedrite occurs with copper pyrites, galena 
and blende. It is worked for copper and occasion- 
ally for silver. 

Chalcopyrite or Copper Pyrites. Massive. 
Color, brass-yellow, when fresh, gold-yellow when 
tarnished. Lustre, sub-metallic ; brittle, slightly 
sectile. Hardness, 3.5 to 4 ; specific gravity, 4.15. 
Composed of copper 34.6, sulphur 34.9, iron 30.5. 
Before the blow-pipe it fuses with intumescence and 
scintillation to a rough magnetic globule. When 
powdered and roasted at a low heat, it is converted 
into a fritted mass, giving reactions of copper and 


iron with fluxes. With soda on charcoal, gives a 
globule of metallic iron and copper. It is sometimes 
mistaken for gold, or iron, or tin pyrites. But it is 
brittle, while gold is not ; it will not strike fire as 
does iron pyrites ; and it may be distinguished from 
tin pyrites by the film that the latter leaves on the 
charcoal, while copper pyrites leaves no residue 
under the blow-pipe. It occurs in granite and slate 
in lodes or veins, and is a valuable ore of copper. 

What is called peacock ore is only pyrites coated 
with oxide and exhibiting iridescent colors. By 
leaving a piece of clean yellow copper pyrites in 
water for some time it will become coated in this 

Chrysocolla or Silicate of Copper. Accom- 
panies other copper ores, occurring especially in the 
upper part of veins. It is a bright green or bluish 
green mineral, scarcely worthy of being called an 
ore, although it contains from 35 to 40 per cent, 
copper and a large amount of silica. It is a second- 
ary deposit. Its hardness is 2 to 4, and specific 
gravity 2 to 2.3. Its only significance to the pros- 
pector is that it may be associated with true ores. 
Its powder (streak) is white, while the mineral itself 
is green ; this being due to the quartz or silex in it. 
It does not entirely dissolve in nitric acid. Before 
the blow-pipe with soda, it gives a bead of copper. 

Black Oxide of Copper is usually found on the 
surface. Soils the fingers when pulverulent. It is 
a result of decomposition of copper ores, as a deposit 
on surface of copper pyrites. It occurs in masses 

COPPER. 165 

of a dark, earthy appearance, sometimes in minute 
shining particles. 

Malachite or Green Carbonate of Copper, 
has a fibrous structure nearly opaque, and of an 
emerald-green color, and contains about 57 per 
cent, of copper. Hardness 3.5 to 4 ; specific gravity 
3.6 to 4. Commonly found near the surface of veins 
containing copper ores. 

Before the blow-pipe it becomes blackish. With 
borax it yields the usual blue-green bead, and on 
charcoal is reduced to metallic copper. It com- 
pletely dissolves in nitric acid, and thus it may be 
distinguished from silicate of copper, which has 
nearly the same color and will not dissolve. 

Azurite or Blue Carbonate of Copper is 
chiefly used for ornamental purposes. It is of a 
deep cobalt blue color sometimes transparent, brittle, 
and gives a bluish streak. It has a hardness of 3.5 
to 4.5 and a specific gravity of 3.7 to 4. Can be 
scratched with a knife. It blackens when heated. 
On charcoal it is reduced to a globule of pure cop- 
per. With the borax bead it gives the indications 
of copper. It is soluble in nitric acid with effer- 
vescence, forming a blue solution. 

Variegated Copper Pyrites (Bomite is the 
mineralogical name, but is also called Erubiscite) : 
Usually massive, of a copper-red to a pinchbeck- 
brown color, and a blackish to lead-gray streak. 
Hardness 2.5 to 3, specific gravity 5.5 to 5.8. It 
contains 79.8 per cent, copper and 20.2 per cent, of 
sulphur. Before the blow-pipe it gives a bead of 

166 prospector's field-book and guide. 

But the minerals above mentioned are by no 
means the most important as regards the commer- 
cial supplies of the metal ; in fact, in that light they 
may almost be disregarded so far as affording any 
considerable proportion of the total yearly output, 
though, of course, deposits of these ores are profit- 
able. The bulk of the world's consumption of cop- 
per is furnished by ores of the lowest grade, ranging 
from little more than J to perhaps 5 per cent., 
though rarely more than 3 to 3J per cent. Thus 
the ores of Devon and Cornwall are worked for 1J 
to 2 per cent, copper ; those of Cheshire, for less than 
1J per cent.; those of Mausfield, Germany, for little 
over 2 J per cent.; those of Eio Tinto, Spain, for 2 J 
to 3 J per cent.; those of Maidenpec, Servia, for 2 to 
3 per cent.; and, overwhelmingly the most abund- 
ant producers, those of the Lake Superior region for 
as little as 0.65 per cent. 

Formerly the world's supply of copper was drawn 
from the rich ores, containing up to 40 per cent, of 
metal as mined, and further explorations may again 
reveal in the future similar deposits to replace those 
now exhausted ; but at present and in the immedi- 
ate future reliance must be placed on the enormous 
low grade ore bodies now being worked, especially 
in North America. 

The geology of copper is more varied than that 
of many other metals, as it occurs in rocks of almost 
every age. In Cornwall the slates are more pro- 
ductive than the granites, while in our mines in the 
Eastern States the new red sandstone, the carbon- 



iferous limestone, and silurian rocks furnish copper. 
Also found in the metamorphic limestone, near 
slate (Fig. 49). In the Lake Superior region, where 
large deposits of native copper are found, the rocks 
are sandstones and shales underlying green-stone or 
a kind of trap, and in some places seem to be igne- 
ous (Figs. 50, 51). Ruby copper ore occurs in Ari- 
zona between quartzose and hornblendic rocks and 

Section of the copper bed at the Dolly Hide mine, Maryland, a, 
Slate, b, b, b, b, Ore beds or segregations of ore. c, c, c, c, Crystalline lime- 
stone (metamorphic). 

limestone. It occurs in both, lodes and deposits, 
and the best way for the prospector to prepare for 
actual discovery is to make himself well acquainted 
with the copper compounds, whether ores or min- 
erals. They may indicate true ores, although they 
contain little copper. 

To become ready in the detection of copper as an 
ore the following facts should be kept in mind, as 



furnishing suggestions for skillful practice. (Figs. 
49, 50, and 51.) 

It is well to remember, especially when exploring 
a new country, that copper is frequently associated 
with rocks of a dark color, which are very often 

Fig. 50. 

«• _K> c 

Section op strata in Lake Superior copper region : a, Granite, b, Gneis- 
soid. c, Greenstone, hornblende, conglomerates with interstratified slates. 
d, Slaty rocks and traps, etc. e, Potsdam sandstone. C, C, Places of copper 
deposits. 0, B, Iron ore beds. Section from N. W. to S. E. 

green ; but it must not be supposed that the color 
is imparted by copper, for it is generally due either 
to some other metal, such as iron, or to the presence 
of a green non-metallic mineral, such as chlorite. 
Serpentines and hornblendic rocks are often associ- 

Fig. 51. 

Copper. Section of the Eagle vein, Lake Superior, a, Poryphyritic 
rocks. 6, Greenstone, c, c, Conglomerate, d, d, d, Amygdaloid bearing 
copper, e, e, e, Shafts. /, Montreal River. 

ated with copper ores, but green serpentines owe 
their color to iron, nickel or chromium, and if cop- 
per is found disseminated through some of them, it 
is the exception and not the rule, unless in the 

COPPER. 169 

immediate vicinity of ore deposits. On the con- 
trary, iron and chromium are found in all serpen- 
tines, and nickel is of frequent occurrence. 

All copper ores weigh more than quartz or lime- 
stone, and the comparative weights should be so 
well known by practice that there should be no 
hesitation in judging that the mineral you hold is 
more than 2.6 in specific gravity, 2.6 being that of 
either quartz or limestone. 

Next examine the mineral with your pocket lens 
for any evidence of copper, such as green or bluish 
spots, or brassy points or particles ; if found, chip 
one off and use the blow-pipe with borax bead or 
with soda or borax on charcoal. If the character- 
istic color appears, it is copper. Now proceed with 
other parts of the specimen. If a sulphury smell is 
plain, it is probably a sulphide. Place a small chip 
upon a depression in the charcoal, cover with soda 
or borax, turn the inner flame upon it and reduce 
to a metallic globule ; if it shows the color of copper 
and is malleable, it is copper ; if it blackens, apply 
your magnetized knife-blade, and if it is attracted, 
the mineral contains iron, and it may contain both 
iron and copper. 

The next work is to examine the region to gather 
any other specimens and evidences of true ores, 
before attempting to know more of any particular 
specimen. If the surface specimens are numerous 
it may be well to gather some six or eight and pro- 
ceed to an examination as to the available copper. 
This is now the work of the chemist, and should be 


submitted to him. But as the skillful prospector 
frequently wishes to be his own chemist, where 
work for the desired object is not difficult nor very 
complicated, we give the following simple process of 
arriving at the per cent, of copper in an ore without 
regard to other elements contained therein : 


The only chemicals needed are nitric acid, ammonia, 
and sodium sulphide — the colorless crystallized hy- 
drosulphide of soda of commerce is good enough. 
All the apparatus needed is a glass flask or tall 
beaker-glass and a marked tall glass called a burette. 
This glass may be obtained at any chemical ware- 
house. The burette is marked in cubic inches or 
cubic centimetres, from 25 to 100. Dissolve some 
sodium sulphide in clear rain-water — about a half 
ounce to a pint. Keep the solution in a glass- 
stoppered bottle. Obtain some pure copper (ordi- 
nary good copper wire will answer), weigh the piece 
accurately and dissolve in nitric acid, add some 
water (twice the amount of acid used, or a little 
more), then add ammonia until, when stirred with 
a long piece of glass or glass rod, the solution smells 
strongly of ammonia. The ammonia must be in ex- 
cess. Now fill the burette with sodium sulphide to 
the 100 mark, and from the burette pour into the 
copper solution until the blue color of copper en- 
tirely disappears ; note on the burette by its marks 
the exact amount of sodium sulphide used. That 
amount represents the weight of the amount of cop- 
per used. 

COPPER. 171 

Now for the ore : Pulverize some of the averaged 
ore, weigh it, and treat it as you did the copper, 
with nitric acid and ammonia, and proceed with 
the sodium sulphide. When the ore solution has 
become entirely colorless, note what amount of 
sodium sulphide solution you have used, and you 
may then calculate the exact amount of copper in 
the ore by simple proportion. The presence of tin, 
zinc, lead, iron, cadmium, antimony, arsenic, or 
bismuth in the ore does not interfere with the oper- 
ation. But silver does. Therefore, a small amount 
of the ore must be dissolved in nitric acid (free from 
all muriatic acid or chlorine, as this would precipi- 
tate the silver before you would notice it), and 
tested by dropping into the solution a drop or two 
of hydrochloric acid or solution of common table 
salt (sodium chloride). If any silver exists in the 
ore a milky cloudiness will appear, of a density 
greater or less in accordance with the amount of 
silver present. If no silver appears, then you may 
proceed as already directed. If silver does appear, 
then the solution containing the weighed ore must 
first be treated with the salt solution or diluted 
hydrochloric acid, until all cloudiness or white pre- 
cipitate entirely ceases. The solution of ore now 
contains no silver, and you may proceed as directed. 

This process is sufficiently accurate for all assays, 
provided the following precautions are observed : — 

1. Heat the copper solution, after adding the am- 
monia, to boiling point or little below while adding 
the sodium sulphide. 2. Add a little ammonia to 


the ammoniacal solution to keep it from losing 
ammonia by evaporation. 3. When the blue am- 
moniacal solution begins to lose its color, drop the 
sodium sulphide in cautiously, so as not to exceed 
the amount necessary to exactly precipitate the 
copper and no more. 

Note the precipitates : The sodium sulphite first 
produces its black precipitate of copper sulphide, 
but before that takes place the ammonia will pro- 
duce another precipitate, provided the copper con- 
tains any lead or tin. If the copper contains zinc, 
that will be precipitated immediately following the 
black copper sulphide, but will be white. If it con- 
tains any cadmium, that will be precipitated at the 
very moment the decoloration takes place, if the 
adding of the sodium sulphide is continued. Cad- 
mium is known by a beautiful clear yellow precipi- 
tate. With care and skill each may be noticed. 

In simply determining the amount of copper, 
however, no regard need be had to any of these 
precipitates, only pay attention to the point of de- 

The sodium sulphide may need proving to see if 
it has lost any of its strength if kept for a long 
time, and this may be done by a trial with a new 
solution holding a known amount of copper. Or, 
exactly the same weight of crystals of sodium sul- 
phide to the same amount of pure water may be 
used as before, and the old solution thrown away. 
Or, by re-testing the sodium sulphide the same so- 
lution may be used for a long time, and if it has 

COPPER. 173 

become weakened, make allowance for the addi- 
tional sodium sulphide required. It should be kept 
in a cool place, out of the sun and light also. 



I. Lead. It very rarely occurs native ; it then 
has a hardness of 1.5 and specific gravity 11.3 to 
11.4. But the most usual ore of lead is the sulphide 
called Galena. When chemically pure it contains 
86.55 lead and 13.45 sulphur. Its specific gravity 
is 7.2 to 7.6, according to admixtures. Streak, lead- 
gray. Color, metallic lead-gray. Easily recognized 
by the characteristic cubical cleavage which is very 
easily obtained, or granular structure when massive. 
Frequently associated with other metallic sulphides 
such as pyrite, chalcopyrite, arsenopyrite, blende, 
etc. It occurs in veins, the gangue of which is 
either quartz, calcite, barite or fluospar, in granite 
and nearly all varieties of rock, but the larger 
deposits are usually found either in veins or in 
pockets, often of great size, in limestone strata. 

Galena almost always contains silver, and hence 
all galenas should be tested for silver. 

Test for Silver in Galena. Powder the 
galena and dissolve it in strong nitric acid (fuming 
acid is best, which has been described), then dip a 
piece of polished copper strip in the solution, and, if 
silver exists in any amount, there will be formed a 
film of silver on the copper. If the thin film be- 



comes decidedly silvery, and in a short time, the ore 
should be laid aside for a more careful analysis. 

The order of strata in the galena district of Wis- 
consin, Illinois and Iowa is shown in the annexed 


f Galena limestone which bears lead. 

1 Trenton limestone, fossils. 
P A M"R"RO- ' 

«! Sandstones, shales, and calcareous beds. 

k Lower magnesian limestones. 

[ Lower limit of lead. 


" Upper — 

Fossiliferous slates. 


Lower — 

Dolomitic limestones. 

Dark sandstones. 

Order of Strata in the Lead District of Wisconsin, Illinois, and Iowa. 

The geology and form of lodes of the galena ores 
are seen in Fig. 52. 

Fig. 52. 

Lead Lode in Micaceous; Slate in Mine near Middletown, Conn. 



In several regions, and extensively so in Colorado, 
a rich carbonate of lead has been found (Fig. 53). 

Carbonate of Lead or Cerussite. If perfectly 
pure its composition is, lead 83.6, carbonic acid 16.4. 
As a mineral its hardness is 3 to 3.5, its specific 

Fig. 53. 

Section of strata in California Gulch. Colorado, showing portion 

OF THE CAF.BONATE OF LEAD DEPOSITS. 0. PorphvritiC TOCk. 12 tO 100 ft. 

thick, b. Thin bed of white clay. c. Carbonate of lead bed. 1 to 20 ft. thick. 
d. Oxide of iron. 1 to 6 ft. thick, e, c. Limestone. /.'Clay slates. <7,'Quartz- 
ites and metamorphic rocks resting upon gneiss. 

gravity 6.4 to Q.o. Color (if freshly broken), white 
to gray, or even black, if it has been much weath- 
ered. If in good condition, it is translucent, or 
even transparent. Very brittle. If it contains 
copper it is usually tinged blue or green. It has a 
glassy or vitreous appearance, and is easily melted 
before the blow-pipe, and a lead bead or globule is 
readilv obtained. 


By using a little bone-ash plastered in a hollow 
in the charcoal and turning the 0. F. upon the lead, 
after a little skillful blowing the lead is absorbed 
and drawn off and a bright silver globule remains, 
provided the lead contains silver. This is blow- 
pipe cupelling. 

Sulphate of lead often accompanies the carbon- 
ate. It somewhat resembles the carbonate, al- 
though it is of slightly less hardness, 2.75 to 3, spe- 
cific gravity 6.12 to 6.3. It may be distinguished 
from the carbonate by the fact that it does not effer- 
vesce in an acid, as the latter always will. Its min- 
eralogical name is anglesite. It is composed of lead 
oxide 73.6 and sulphuric acid 26.4 in the pure 

Phosphate of lead. Mineralogically, pyromor- 
phite. Composition, when pure, S9.7 phosphate 
and 10.3 chromate of lead, with arsenate of lead (0 
to 9), phosphate of lime (0.11), and fluoride of cal- 
cium. Hardness, 3.5 to 4: specific gravity, 6.o to 7; 
color, green with modifications. It has a resinous 
lustre and is translucent; contains 7S per cent. lead. 
Heated on charcoal before the blowpipe a globule 
is formed which takes on a crystalline appearance 
on cooling, leaving a yellow oxide of lead on the 
charcoal. AVith carbonate of soda in the reducing 
flame it yields a yellow globule. It is soluble in 
nitric acid. 

Crocoite or Chromate of Lead is a yellow 
mineral containing protoxide of lead 68.15, chromic 
acid 31. 85. Hardness 2.5 to 3 ; specific gravity 5.9 

178 prospector's field-book and guide. 

to 6.1. Color, various shades of bright hyacinth- 
red, streak (powder) orange-yellow. Lustre, vitre- 
ous. Translucent, and sectile. 

Massicot or Lead Ochre. This mineral occurs 
massive, as a compact earth of a sulphury-yellow or 
reddish-yellow appearance. It has a hardness of 2, 
a specific gravity of 8, and, when pure, 9.2. It is 
composed of oxygen 7.17, lead 92.83. Before the 
blow-pipe it fuses readily to a yellow glass, and on 
charcoal is easily reducible to metallic lead. 

Lead-Antimony Ores. There are several com- 
pounds of lead with antimony, but they are never 
sufficiently plentiful to be considered as ores. One 
of these, jamesonite, contains small proportions of 
iron, copper, zinc and bismuth. It occurs in gray 
fibrous masses or small prisms, and is found in 
Cornwall associated with quartz and bournonite. 
Another of these compounds, zinkenite, resembles 
stibnite and bournonite, and occurs in an antimony 
mine in the Hartz. 

The geology of lead. Almost all the galenas 
and the carbonates contain silver, and some of the 
latter, as in Colorado, contain large quantities of 
silver. The geology of lead is very much the same 
as that of silver. 

The ores are found in veins and lodes, and also 
in flats and beds, and in pockets (Fig. 54). The 
galenas occur in limestones, called the "galena 
limestones," a yellowish-gray, hard, compact crys- 
talline rock. The lowest horizon of lead ore in 
workable quantities lies above that of copper. 



" The limestones and underlying schists are, for 
the most part, in a metamorphic condition, and 
there can be no difficulty, from the presence of 
porphyry above and the quartzites and gneiss 
below, in recognizing their position," * as in the 
Cambro-silurian system. It is supposed that the 
largest proportion of silver is contained in the ore 
derived from this geologic horizon. 

Fig. 54. 

Section of Galena limestone showing how the lead occurs in lodes, a, 
flats, b, b, b, and pockets, c, from mere threads to several feet of thickness. 

When water has had its course, however, the 
condition of a mine and of its veins and beds of ore 
may have been changed. Robert Hunt, as it re- 
gards British mines, says, that the circulation of 
water in the veins is affected by the inclination of 
the strata in the direction of the vein. The richest 
deposits are found in that portion of strata which is 

* B. C. Davies. F. G. S. A Treatise on Metalliferous Minerals 
London, 1892, p. 259. 

180 prospector's field-book and guide. 

the most elevated, for instance, on the side of a 
powerful cross vein, Fig. 55, thus : 

The circulation of water is dependent upon an 
outlet at a lower level. 

In the case of lead mines, it is stated that in 
consequence of the conditions connected with the 
descent of water, the richest deposits of lead are 
generally found at no great distance from the out- 
cropping of the containing rock. Veins which run 

Fig. 55. 

on the sides of a mountain in a direction nearly 
parallel with the valleys contain more extensive 
deposits of lead than those which cross the valleys 
at right angles.* 

The prospector should keep this suggestion in 

The lead ores are found in the fissures where they 
seem to have been deposited by waters which have 
dissolved them out from neighboring beds (Fig. 56). 

In the United States the chief sources of lead in 
late years have been argentiferous ores and consid- 
erable from zinc ores, but a notable exception is 

* British Mining, by Kobert Hunt, London, 1884, p. 344. 



S. E. Missouri, where galena accompanied by nickel- 
iferous pyrite is disseminated through magnesian 
limestone of Cambrian age. The mines are at 
Bonne Terre, Mine la Motte and Doe Run. The 
strata lie almost horizontal, and are known to carry 
lead through over 300 feet in thickness. 

II. Tin. When a tin-bearing mineral is heated 

Section op a Lead Deposit in a Fissure of the Limestone. Williams & 
Co.'s Mine, Wisconsin. B, B, B, B, limestone. A, the fissure running down. 
C, C, C, C, masses of ore. Metamorphic. 

before the blow-pipe with carbonate of soda or char- 
coal, white metallic tin is yielded. By dissolving 
this in hydrochloric acid and adding metallic zinc, 
the tin will be deposited in a spongy form. In the 
blow-pipe assay tin leaves behind a white deposit 
which cannot be driven off in either flame. If it 
be moistened with nitrate of cobalt solution, the 
deposit becomes bluish-green, and this test distin- 
guishes it from other metals. 

Assay of tin ore. If the ore is poor it should be 
concentrated, the vein-stuff being got rid of as much 

182 prospector's field-book and guide. 

as possible. If mixed with iron or copper pyrites, 
it should be calcined or else treated with acids. 
One method is to mix the ore with one-fifth of its 
weight of anthracite coal or charcoal, and expose it 
in a crucible to a great heat for about twenty min- 
utes. The contents are then poured out into an 
iron mould, and the slag carefully examined for 

Another method is to mix 100 grains of the ore 
with six times its weight of cyanide of potassium, 
and expose the mixture to the heat of a good fire 
for twenty minutes. The contents are allowed to 
cool and afterwards broken to remove the slag. 

Cassiterite or Tin Stone. This mineral forms 
the principal source of tin, and when pure contains 
78.6 per cent, of metallic tin. It is remarkable for 
its hardness (6 to 7), and still more so for its specific 
gravity (6.8 to 7). It contains small quantities of 
iron, copper, manganese, tungsten, tantalic acid, 
arsenic, sometimes silica and rarely lime. It is 
found associated with quartz, mica, topaz, tourma- 
line, wolfram, chlorite, iron copper, and arsenical 
pyrites. It occurs massive and in crystals, also in 
botryoidal and reniform shapes, concentric in struct- 
ure and radiated fibrous, and is then in the last 
form called wood tin, from its woody appearance. 
Toad eye tin is the last described, but in very small 
shot-like grains. Stream tin is nothing but the ore 
in a state of sand as it occurs along the beds of the 
streams or the gravel of the adjoining region. It 
has been derived from tin veins or rocks. 


Cassiterite yields a white, greyish, or brownish 
streak ; has a brownish color and a dull lustre. It 
is nearly as hard as quartz, and will scratch glass, 
especially if freshly broken. Pure crystals are rare. 
They are nearly transparent, but in the mass, as it 
occurs in the mines in Dakota and in many other 
places, the ore is a dark brown color, and sometimes 
almost black ; the fine powder or streak as made by 
a file, is light brown, however dark the mineral 
may be. The brown color or shade is due to oxide 
of iron in composition ; if perfectly free from all 
associated impurities it would be nearly white or 
colorless. The usual appearance in mass or pebbles, 
or finer, is that of a dirty or burned-brown color 
with varying depths of shade. 

In the pebble form it is apt to wear quite smooth, 
due to its extreme hardness. 

It was in this form that it was discovered in 
Banca, in 1710, and in the neighboring island, 
Billiton, and traced to its source in the mountains, 
where the central rock is granite, covered by quartz- 
ites, altered sand-stones, and slaty rocks. The 
altered sandstone just above the granite is the most 
productive rock, and it is traversed in all directions 
with tourmaline.* The same general associations 
largely exist in Wyoming and Dakota tin mines. 

There is another mineral containing tin which 
may lead to the discovery of the true ore. It re- 
quires only a short description, which we give. 

* D. C. Davies, F. G. S. , Metalliferous Minerals, London, 1892, 
p. 194. 


Tin pyrites (sulphide of tin) whose composition is, 
as a mineral, 29 to 30 sulphur, 25 to 31 tin, 29 to 
30 copper, with iron and sometimes zinc. It has 
been dug as an ore of copper and called " bell- 
metair Its hardness is 4 ; specific gravity 4.3 to 
4.5 ; has a metallic lustre ; color, steel-gray to black, 
often yellowish from the presence of copper sul- 
phide ; it is opaque and brittle. 

With nitric acid it affords a blue solution, and 
sulphur and tin oxide separate and may be tested 
on charcoal, where it fuses to globule, which, in 
the oxidizing flame, gives off sulphur and coats the 
coal with white oxide of tin. 

This ore or mineral, for it does not as yet deserve 
the name of tin ore, is of little use, but the pros- 
pector does well to make himself acquainted with it, 
as it is frequently associated with the binoxide or 
cassiterite, or black oxide, as the true ore is fre- 
quently called. 

In the United States, cassiterite occurs in small 
stringers and veins on the borders of granite knobs 
or bosses, either in the granite itself or in the adja- 
cent rocks, in such relations that it is doubtless the 
result of fumarole action consequent on the intru- 
sion of the granite. It appears that the tin oxide 
has probably been formed from the fluoride. The 
Cajalco mine in California and the Harvey Peak 
mines, South Dakota, have been developed, but it is 
questionable whether they are worked at a profit. 
Undeveloped deposits are reported in Alabama, 
North Carolina and Virginia. At Broad Arrow, 


near Ashland, Alabama, tin-ore is disseminated in 
gneiss, the ore averaging about 1J per cent, black 
tin, but being very much mixed with titaniferous 
iron. At King's Mountain, North Carolina, cassi- 
terite occurs very irregularly in a (( greisen " or 
altered granite, and in limited alluvials derived 
from the disintegration of the same. On Irish 
Creek, Virginia, experimental parcels of vein-stone 
taken from deposits in granite have shown 3£ to 3J 
per cent, metallic tin, largely associated with arsen- 
ical pyrites and ilmenite, which increase the diffi- 
culties of concentration and lower the value of the 

Cassiterite stands nearly by itself in its mode of 
occurrence and formation, as a type of a strongly 
marked class of deposits. It is always associated 
with granitic rocks, quartz-porphyries, or gneiss, all 
of which are of analagous composition, being rich in 
silica, which crystallizes as quartz, and being called 
in consequence " acidic " rocks. Tin lodes are 
nearly all of great antiquity and occur only in 
those of the above-named rocks which are charac- 
terized by the presence of white mica. It is only 
in two or three places in the world, notably Tus- 
cany and Elba, that granites of this type have been 
erupted during recent times, and they contain tin in 
small quantity as well as some of the minerals 
usually associated with it, such as tourmaline, 
lithia, mica, and emerald. 

Although this fact is of no immediate practical 
value, it is important, because it shows that there 

186 prospector's field-book and guide. 

really are laws which govern the distribution of 
minerals, although these are sometimes very ob- 
scure ; but by constant observation it is certain that, 
amongst discoveries of merely scientific interest, 
laws capable of practical application will occasion- 
ally be found. 

Cassiterite is always associated with quartz and 
rarely occurs in green rocks, unless their color be 
due to chlorite ; nor in dark-colored rocks, except 
where stained red by the decomposition of ferru- 
ginous minerals ; neither is it found in limestone. 

Those granites which are characterized by abund- 
ance of white mica have, with good reason, been 
termed "tin granites," and a coarse-grained rock 
composed of granular quartz mixed with white mica 
and called "greisen" occurs in all the tin fields of 
the world. 

The minerals most commonly associated with tin, 
namely topaz, mica, tourmaline, fluorspar, apatite 
and other rarer minerals containing fluorine, seem 
to show that it was originally contained in the 
granite as fluoride of tin, and that the associated 
minerals have been formed at its expense. It is an 
established fact in the genesis of minerals that fluor- 
ine is always accompanied by silicon and boron. 
It is therefore natural to find silicates containing 
boric acid, such as tourmaline and axinite, in asso- 
ciation with tin. Other minerals which frequently 
accompany this metal are wolfram, molybdenite, 
mispickel, garnet, beryl, etc. 

It is evident that a most important aid to the 


prospector is a study of the characteristics of the 
tinstone ores, and he may find it beneficial to be- 
come acquainted with the special minerals above 
mentioned as associated with the ores. 

These minerals include, in some mines, wolframite, 
which gives trouble in the Cornwall and other tin 
mines, and the following description and tests may 
aid in detecting it : 

Wolframite is in hardness 5-5.5, specific gravity 
7.1-7.55, therefore, in these features it resembles the 
tin oxide ; though somewhat softer, yet the specific 
gravity is practically the same, although really 
heavier. So in color it frequently closely resembles 
tin oxide. But in the streak (or scratch powder), 
wolframite is a dark reddish-brown to black, while 
the tin oxide gives a white or grayish-brown pow- 
der ; wolframite is opaque, while the tin oxide is 
translucent and sometimes transparent on the edges ; 
when mixed with iron or manganese rarely, it looks 
almost opaque. Composition of wolframite : Tnng- 
stic acid about 75, the remainder protoxide of iron 
and manganese protoxide, more of the latter than 
of the former. 

Wolframite is used in the preparation of some 
colors and enamels, and enters into the composition 
of some special kind of steel. Tungstate of soda 
which is used as a mordant and for fire-proofing 
fabrics, is also prepared from it. 



I. Zinc. Zinc is never found free in nature, but 
chiefly occurs in combination with carbonic acid and 
united with sulphur. The chief ores are : 

Smithsonite or zinc carbonate. Composition, 
zinc 51.44, oxygen 13.10, carbonic acid 35.46. But 
the composition in the mines varies because of the 
presence of protoxide of iron, manganese and mag- 
nesia. Color, when pure, nearly white, through 
various shades of yellow and gray to brown. Hard- 
ness 5 ; specific gravity 4-4.4. Streak, uncolored 
or white. Lustre, vitreous, pearly, subtransparent 
to translucent. Found in veins, but more usually 
in irregular deposits in limestone strata. 

It is easily detected by the blow-pipe, as it gives a 
green color when heated after being moistened with 
half a drop of nitrate of cobalt solution. On char- 
coal, with soda, it coats the charcoal with a white 
film, which is yellow when hot and white on cool- 
ing, but if moistened with the cobalt solution and 
heated in the F it turns green. "With muriatic 
acid it effervesces and dissolves. In mass it is 
translucent and brittle. 

Calamine. This is a silicate of zinc. Composi- 


tion, zinc oxide 67.5, silica 25, water 7.5. Hardness 
4.5-5, the latter when crystallized (Dana); specific 
gravity 3.16-3.9. Color and streak the same as in 
Smithsonite. Acts before the blow-pipe as does 
Smithsonite, but does not effervesce with acids, and 
gelatinizes ; it is soluble in a strong solution of pot- 
ash. In physical characters zinc silicate somewhat 
resembles zinc carbonate. An anhydrous variety of 
this ore is Willemite, which is found in New Jersey 
(Mine Hill and Sterling Hill). Zinc silicate is usu- 
ally found in veins or in beds or in irregular pock- 
ets in stratified calcareous rocks, in association with 
zinc blende, zinc carbonate, iron, lead ores, etc. 

Zincite on red oxide of zinc. Its composi- 
tion is zinc 80, oxygen 20, varied by the presence 
of 3 to 12 parts of peroxide of manganese, which 
gives the red color, for zinc oxide, pure, is white. 
The ore is peculiar to one region in New Jersey, 
Franklin, Sussex Co. Hardness 4-4.5 ; specific 
gravity 5.4-5.7 ; color, red and yellowish-red, streak 
the same ; translucent, brittle. 

Sulphide of zinc, mineralogical name sphalerite 
or blende, miners' name black-jack. Composition, 
zinc 66.8, sulphur, 33.2, but varied in the mines by 
iron, and sometimes cadmium. Color varies from 
yellow to brown and almost black, having a waxy 
look. Hardness 3.5 to 4; specific gravity 3.9 to 4.2; 
brittle, translucent. Zinc blende is the most abun- 
dant zinc ore. It occurs in rocks of all ages, in 
veins, in contact deposits or in irregular pockets in 
limestone, etc., and is frequently associated with 



the ores of lead, as well as those of copper, iron, sil- 
ver, gold and tin ; also, frequently associated with 
quartz, barite, fluorite, calcite, etc. It is easily re- 
cognized if treated with hot hydrochloric acid, as 
it gives a smell of rotten eggs (sulphuretted hydro- 
gen), and the same results can be obtained without 
heating if a small quantity of pure iron filings is 
added to the acid. With soda on charcoal before 
the blow-pipe, zinc blende gives a sulphuret which, 
with water on a silver coin, tarnishes or blackens it. 
The geology of zinc and of lead are so nearly 

Fig. 57. 

Section of strata near Sparta, New Jersey, zinc mines. 
a, Slaty rock with feldspathic dykes, b, b, Limestone, c, Franklinite iron 
ore with zinc 20 to 30 ft. wide, d, Red oxide of zinc 3 to 9 ft. wide, e, e, 
Crystalline limestone. /, Feldspathic rock. 

alike that what has been said of the latter will apply 
to the former (Fig. 57). 

In New Jersey a section of strata near Sparta 
shows slaty rock with feldspathic dykes, then lime- 
stone adjoining the Franklinite iron ore with zinc 
20 to 30 feet wide, then the red oxide of zinc 3 to 9 
feet wide, then crystalline limestone, and next feld- 
spathic rock (Fig. 57). 


Enormous and extensive deposits of the sulphide 
are reported as occurring in Colorado, at George- 
town and Mount Lincoln, and in Montana, near 
Jefferson City. 

The blow-pipe shows the same tests for zinc as 
have previously been mentioned. The fumes of 
sulphurous acid may be easily noticed when the 
mineral is placed in an open tube of glass (a test 
tube with a small hole in the bottom will be suffi- 
cient), and is strongly heated. 

II. Iron. This metal is one of the most abundant 
and widely disseminated elements of the earth's 
crust, its distribution being materially aided by the 
fact of its forming two oxides of different chemical 
quantivalence. Native iron is not found in nature, 
but occurs with a small percentage of nickel in 
meteorites. It resembles ordinary iron, is malleable 
and attracted by a magnet. Specific gravity 7.0 to 

The chief ores of iron are magnetite, hematite 
(red and brown), and black band. 

Magnetite or magnetic iron ore, is found in 
octahedral or decahedral crystals ; more commonly 
simply massive. Streak black ; color, black. Com- 
position, iron 72.4, oxygen 27.6. Hardness, 5.5 to 
6.5 ; specific gravity, 5 to 5.1. The ore is always 
easily attracted by the magnet, and sometimes is 
found capable of attracting iron and is then called 
polaric or loadstone. In powder or small grains it 
is always attractable by a magnetized knife blade. 

The usual geological position of magn^tite'is in 

192 prospector's field-book and guide. 

the most highly met amorphic rocks, in which it 
probably represents the excess of iron oxide origi- 
nally in the rock which was not taken up by silica. 
Occasionally it is found in layers, but in this coun- 
try and elsewhere it forms whole mountains. 
Among other rocks in which it occurs the following 
are the most important : Crystalline limestone, chlor- 
ide, talcose, hornblendic, pyroxenic and hypers- 
thenic schists ; serpentine, diorite and basalt. Spec- 
ular iron is frequently associated with it. 

Magnetite is not acted upon by nitric acid, but 
hydrochloric acid dissolves it when in very fine 
powder, and under long-continued heat. 

Iron exists in magnetite as protoxide and per- 
oxide or FeO and Fe 2 3 , and upon this difference 
of oxides is based the action of important tests. 

Franklinite is. an ore somewhat resembling 
magnetite in color, hardness, and specific gravity, 
but it contains manganese and zinc, and as an ore, 
is peculiar to Sussex Co., New Jersey. Its streak is 
dark brown, and its action on the magnet is feebler 
than in the case of magnetite. The iron is said to 
be of the composition of peroxide, or Fe 2 3 , but it 
is probably in part protoxide, and this is the cause 
of its feeble effect on the magnet. 

It is easily affected under the blow-pipe. Alone, 
it is infusible, but with borax in the Fit colors 
the borax bead with the amethystine color of man- 
ganese, and in the R F it shows the bottle-green of 
iron. On charcoal with soda it gives the bluish- 
green manganate, and also the coating of zinc, 


especially if the soda is mixed with borax. It is 
soluble in fine powder in muriatic acid. 

Specular ore is the peroxide of iron without the 
protoxide. This oxide is also called the sesqui- 
oxide, or one and a half oxides, since iron combines 
with oxygen in the proportion of one to one and a 
half parts, or Fe 2 3 , and this is the highest propor- 
tion of oxygen the iron will combine with, and 
hence it is the peroxide, the peroxide and sesqui- 
oxide being the same in this case. 

Specular ore is called red hematite from its 
color, which in some masses is so intensely red as to 
appear nearly black, but it may always be distin- 
guished from magnetite by its red streak, and the 
blacker the ore the more decided is the red of its 
powder or streak. It is never magnetic. We have 
always found that in cases where specular ore 
showed any magnetic attraction, it was due to the 
fact that the ore contained some protoxide of iron. 

Hardness 5.5; specific gravity 4.5 to 5.3; composi- 
tion, 70 per cent, iron, 30 per cent, oxygen. Color, 
reddish to almost black. 

Brown Iron Ore or Brown Hematite or 
Limonite. This is the same composition as red 
hematite, except that it has less iron and contains 
water in chemical combination, generally about 14 
per cent. Color always brown. When heated red- 
hot it loses its water and turns to a bright-red, unless 
largely mixed with alumina and silex, when the 
red color is shaded. It is not magnetic unless 

194 prospector's field-book and guide. 

heated with soda under the blow-pipe, when it be- 
comes metallic, as all iron ores do. 

The amount of metallic iron in a pure specimen 
is 59 per cent., sometimes decreased by the presence 
of alumina, silica, magnesia, and other impurities, so 
that its average in many good mines is only about 
35 to 36 per cent. iron. 

Spathic Iron Ore or Siderite is an iron car- 
bonate, composed of iron protoxide 62 per cent, and 
carbonic acid, or 48 per cent, pure iron. Hardness 
3.5 to 4.5 ; gravity 3.7-3.9 ; streak white. Color 
gray or cream color, unless weathered, when it is 

When in powder it effervesces with muriatic acid, 
especially when hot. Translucent on edges, and 
thin plates or splinters. 

With the blow-pipe in a closed tube (test tube) it 
decrepitates, becomes blackened, and gives off car- 
bonic acid. Before the blow-pipe alone, held by 
forceps, it blackens and fuses. In the test-tube with 
muriatic acid it may be tested for carbonic acid, by 
letting a lighted thread down into the tube, when 
the flame is instantly extinguished. The solution 
in the tube may be tested for iron by dropping a 
drop of solution of ferri cyanide of potassium into the 
muriatic acid solution, when it becomes instantly a 
deep blue. This is a test of protoxide of iron, spathic 
ore being iron in the condition of protoxide only. 

Black band ore is an argillaceous spathic ore of 
various dark colors, being largely combined with 
carbonaceous material. It is found extensively in 


Great Britain, near the summit of the coal measures. 
In our country the black band ores are also associ- 
ated with the coal measures, both in the anthracite 
and bituminous regions. 

Chromic Iron or Chromite, generally with 49.90 
to 60.04 per cent, of chromic oxide, 18.42 to 35.68 
per cent, of ferrous oxide, 10 to 12 per cent, alumina, 
5.36 to 15 per cent, magnesia, and 4 to 6 per cent, 
silica, occurs usually massive, mixed with other iron 
ores or in serpentine. It is of an iron-black to brown- 
ish-black color and a faintly metallic lustre. Streak 
or powder, dark-brown. Fracture, irregular; specific 
gravity, 4.4 to 4.6; hardness 5.5, is not scratched by 
a knife. With borax bead it gives the character- 
istic indications of chromium. It is largely used in 
the preparation of chromium colors. 

The following iron ores are not used for the mak- 
ing of iron and steel, but may nevertheless prove of 

Iron Pyrites, usually in cubes and allied forms, 
sides often marked by fine parallel lines. Occurs 
also massive and contains 46.7 per cent, of iron and 
53.3 per cent, of sulphur. Color, brass yellow ; 
lustre, metallic ; streak, brownish-black ; fracture 
irregular ; specific gravity 4.8 to 5.1 ; hardness 6 to 
6.5 ; cannot be scratched with a knife, but is 
scratched by quartz, and scratches glass with great 
facility. Before the blow-pipe it burns with a blue 
flame, giving off an odor of sulphur, and ultimately 
fuses into a black magnetic globule. It is found in 
great abundance, and is used as a source of sulphur. 

It is easily distinguished from -copper pyrites by its 
hardness, the latter being readily cut with a knife. 
From gold it is distinguished by its hardness and in 
not being malleable, and in giving off sulphurous 
odors in the blow-pipe flame. 

Arsenical Pyrites or Mispickel contains 34.4 
per cent, of iron, 19.6 per cent, of arsenic, and 46.0 
per cent, of sulphur. It occurs in flattened prisms 
and also massive. Color, white ; lustre, metallic ; 
streak, gray ; fracture, uneven ; specific gravity 6.0 
to 6.3 ; hardness 5.5 ; cannot be scratched with a 
knife, but is scratched by quartz. Heated before 
the blow-pipe it gives off white arsenical fumes of a 
garlic odor, and finally fuses into a black globule. 
It is abundant in mining districts, and sometimes is 
auriferous. With the improved processes now in 
use, it is possible to extract the gold profitably, and 
hence mispickel ores should be examined for gold. 

The Geology of the iron ores varies and may be 
divided into that of the magnetites, which are al- 
ways derived from the granites, gneiss, schist rocks, 
clay slates, and, rarely, the metamorphic limestones. 

The red hematites seem to be only an alteration 
derived from the magnetites, and belong to the 
same more ancient rocks as the latter. 

The brown hematites (limonites) are derived from 
both the former and are generally sedimentary. 

Very frequently in extensive magnetic regions, 
where the country back is mountainous, the brown 
ore has been formed in basins and knees and inter- 
locked portions of the lower country, where ages of 



rains, storms and freshets have gradually trans- 
ported and altered the magnetic ores of the upper 
regions and brought down these iron oxides to the 
low lands, where they have been arrested and set- 
tled down in beds of brown hematite. This seems 
to have been the history of all the hematitic limonite 

Fig. 58. 

Geological Horizons around the Iron Ores op Lake Superior. 
a. Gneiss, b, Hornblende slates, c. The same with numerous thin beds 
of iron ore which frequently unite, d. Potsdam sandstone. 

beds and deposits ; they are on the lower levels 
when they were formed, although in after ages they 
may have been uplifted. 

Iron ores are, therefore, to be found in three gen- 
eral geologic regions : (1) in the earliest rocks ; (2) 
in the carboniferous, and (3) in the more recent or 
sedimentary rocks, and in accordance with their 



composition as magnetites and specular ores, as 
carbonaceous or black band and spathic ores, or as 
brown ores of the limonite order. 

One of the most peculiar geologic conditions is 




1) a 

Section of Pilot Knob, Missouri. 
a. Quartzite or siliceous rock. b. Red hematite iron ore alternating with 
siliceous matter, c. Siliceous rocks. 

found in the Pilot Knob Mountain, wherein the 
iron strata have been thrown up as in Fig. 59. 


In ordinary cases, where the surface is covered 
with loose earth, it is common to search for mag- 
netic iron ore with a magnetic needle or a miner's 
compass, and for preliminary examinations it is 
now the chief reliance. In using this instrument 
considerable practice is required ; but this joined to 
good judgment gives indications of the presence of 
ore which are almost infallible. There has been 
very great improvement, within a few years past, in 


the methods of searching for magnetic ore as well 
as in the instruments to be used for that purpose, 
and the work is now well done by many persons. 

In the Annual Keport of the State Geologist of 
New Jersey for 1879, W. H. Scranton, M. E., makes 
a report, accompanied by a map, upon a magnetic 
survey made at Oxford, Warren Co., New Jersey, to 
determine the location of a vein, and the proper 
places to sink shafts. Mr. Scranton finds Gurley's 
Norwegian compass the best, though the slowest to 
work with. He sums up the indications from the 
magnetic needle in searching for ore, as it usually 
occurs in New Jersey, as follows : 

" An attraction which is confined to a very small 
spot and is lost in passing a few feet from it, is most 
likely to be caused by a boulder of ore or particles 
of magnetite in the rock. 

" An attraction which continues on steadily in the 
direction of the strike of the rock for a distance of 
many feet or rods, indicates a vein of ore ; and if it 
is positive and strongest towards the southwest, it is 
reasonable to conclude that the vein begins with the 
attraction there. If the attraction diminishes in 
going northeast, and finally dies out without becom- 
ing negative, it indicates that the vein has con- 
tinued on without break or ending until too far off 
to move the compass needle. If, on passing towards 
the northeast, along the line of attraction, the south 
pole is drawn down, it indicates the end of the vein 
or an offset. If, on continuing further still in the 
same direction, positive attraction is found, it shows 

that the vein is not ended ; but if no attraction is 
shown, there is no indication as to the further con- 
tinuance of the ore. 

" In crossing veins of ore from southeast to north- 
west, when the dip of the rock and ore is as usual to 
the southeast, positive attraction is first observed to 
come on gradually, as the ore is nearer and nearer 
to the surface, and the northwest edge of the vein is 
indicated by the needle suddenly showing negative 
attraction just at the point of passing off it. This 
change of attraction will be less marked as the 
depth of the vein is greater, or as the strike is nearer 
north and south. The steadiness and continuance 
of the attraction is a much better indication of ore 
than the strength or amount of attraction is. The 
ore may vary in its susceptibility to the magnetic 
influence from impurities in its substance ; it does 
vary according to the position in which it lies — 
that is, according to its dip and strike ; and it also 
varies very much according to its distance beneath 
the surface. 

" Method of Using the Compass in Searching for Ore. 
— It is sufficient to say that the first examinations 
are made by passing over the ground with the com- 
pass in a northwest and southeast direction, at in- 
tervals of a few rods, until indications of ore are 
found. Then the ground should be examined more 
carefully by crossing the line of attraction at inter- 
vals of a few feet, and marking the points upon 
which observations have been made, and recording 
the amount of attraction. Observations with the 


ordinary compass should be made and the varia- 
tion of the horizontal needle be noted. In this way 
material may soon be accumulated for staking out 
the line of attraction, or for constructing a map for 
study and reference. 

" After sufficient exploration with the magnetic 
needle, it still remains to prove the value of the 
vein by uncovering the ore, examining its quality, 
measuring the size of the vein, and estimating the 
cost of mining and marketing it. Uncovering 
should first be done in trenches dug across the 
line of attraction, and carried quite down to the 
rock. When the ore is in this way proved to be of 
value, regular mining operations may begin. 

" In places where there are offsets in the ore, or 
where it has been subject to bends, folds, or other 
irregularities, so that the miner is at fault in what 
direction to proceed, explorations may be made with 
the diamond drill." 



I. Mercury or Quicksilver. At ordinary tem- 
peratures it is fluid, a character which no other 
metal possesses. The usual properties of a metal 
are, however, highly developed in it, and when 
solid it has much resemblance to silver, especially 
in its high metallic lustre, ductility, malleability, 
its capability of being cut with a knife, its granular 
fracture, and its high degree of conductibility of 
heat and electricity. It is sometimes found native, 
either as globules disseminated through its ores, or 
in rocks containing them. It is bright white and 
of specific gravity 13.6 at 50° F., and about 15.6 
when solid. 

Mercury readily combines with most of the other 
metals, and the compounds thus formed are called 
amalgams. The amalgams with the heavy elements 
are generally easy of decomposition, and hence it is 
exceedingly useful for the extraction of gold and 
silver from their ores or matrices. The mercury 
picks up the almost invisible specks of gold, and in 
this way the gold is concentrated into a compara- 
tively small space. By heating the amalgam the 
mercury is driven off and the gold is separated in 
nearly pure form. 



Mercury is most commonly found in association 
with sulphur. Antimony is also a frequent com- 
panion, but not in chemical union. The ore of 
greatest industrial importance is 

Cinnabar, or sulphide of mercury, found massive, 
of a granular texture, reddish color, and scarlet-red 
streak. Composition : Mercury 86.2, sulphur 13.8, 
when pure. It is the only regular and most valu- 
able ore of mercury. 

Hardness 2 to 2.5 ; specific gravity 8.99 ; sectile. 
Easily scratched with a knife, affording a deep red 
streak. Before the blow-pipe on charcoal it is vola- 
tile if pure, gives sulphurous fumes if heated in an 
open tube, and mercury condenses on the sides of 
the tube, so that it may easily be seen with a lens 
or even the naked eye. 

There is also a black sulphide, called metacinna- 
barite, found in one locality in California ; and, in 
California and Mexico, a sulphoselenide named 
guadalcazarite (81J per cent, mercury, 10 sulphur, 
6J selenium) is sometimes encountered. 

Native Amalgams. Only two native amalgams 
are known, namely, those with silver and gold. As 
in all alloys the proportions of the constituents vary, 
and the properties of a specimen will vary according 
as the silver, the gold or the mercury predominates. 
The native amalgam most frequently found is a 
mixture of silver and mercury, and when pure con- 
tains from 64 to 72 per cent, mercury. Color, sil- 
ver white ; hardness, 3 to 3.5 ; specific gravity 10.5 
to 14. On charcoal before the blow-pipe, the mer- 
cury evaporates, and the silver remains. 

The quicksilver deposits at Aim ad en, in Spain, 
have a far remote history, for in the time of Pliny 
10,000 lbs. were sent annually to Kome from these 
mines. They occur in upper Silurian slates, some- 
times interstratified with beds of limestone ; but the 
ordinary slates themselves, which are much con- 
torted, rarely contain cinnabar. The enclosing 
rock usually consists of black carbonaceous slates 
and quartzites alternating with schists and fine- 
grained sandstones. 

At Idria, Austria, cinnabar is found in impreg- 
nated beds and stockworks, in bituminous shales, 
dolomitic sandstones and limestone breccias of tri- 
assic age, dipping 30° to 40°, and covered by car- 
boniferous sandstones and shales in a reversed 
position. This deposit has been worked for nearly 
400 years, and is said to become richer as the depth 

The quicksilver-bearing belt of California extends 
along the coast range for a distance of about 200 
miles. According to a report by M. G. Holland, 
these deposits are generally impregnations in the 
cretaceous and tertiary formations. They seem to 
be richer when the beds are more schistose and 
transmuted. They are more or less closely in rela- 
tion with serpentines, which are themselves some- 
times impregnated with oxide of iron, sometimes in 
quartzose schists, in sandstones, more rarely in 
limestone rocks, limestone breccias, etc. Native 
mercury is found in some magnesian rocks near the 
surface. There are no defined fissures nor veins 


proper. The cinnabar with quartz, pyrites, and 
bituminous substances is sometimes disseminated in 
the rock in fine particles and spots, sometimes forms 
certain kinds of stockworks or reticulated veins and 
nests. The parts thus impregnated congregate and 
form rich zones, the size of which occasionally 
reaches 80 fathoms, and the percentage 35 per cent., 
and flat-like veins or lenticular deposits, the strike 
and dip of which agree with those of the schists of 
the country generally. These rich zones without 
denned limits gradually merge into poor stuff con- 
taining half a per cent., or more traces, and are of 
no value. 

Sulphur Bank, one of the principal mines, was 
originally worked as a sulphur deposit. Sulphur 
in workable quantities is known to exist in some 
volcanic countries, and volcanic rocks are abundant 
at the California cinnabar mines. 

II. Bismuth. This metal occurs native, of a red- 
dish silver-white color. Brittle when cold ; hard- 
ness 2-2.5 ; specific gravity 9.7. Malleable and 
sectile when heated, but breaks under the hammer. 
It carries, sometimes, traces of arsenic, sulphur, tel- 
lurium and iron. On charcoal before the blow-pipe, 
it fuses and entirely volatilizes, leaving a coating 
which is orange-yellow while hot and lemon-yellow 
on cooling (this is the trioxide of bismuth). It dis- 
solves in nitric acid, but subsequent dilution causes 
a white precipitate. 

Very little bismuth has been found in our coun- 
try. The metal occurs on the Continent of Europe, 

206 prospector's field-book and guide. 

associated with silver and cobalt, also with copper 
ores. Although there is but little call for it in the 
arts, a deposit or lode of bismuth would be valuable. 

Where it has been found in the United States it 
has been associated with wolfram (tungstate of iron 
and manganese), also with tungstate of lime, with 
galena and zinc blende in quartz. 

Its Geology is the same as that of copper ; it 
occurs in veins in gneiss and other crystalline rocks 
and clay slate, accompanying ores of silver, copper, 
lead and zinc. 

III. Nickel. It does not occur native except in 

Under the blow-pipe, nickel requires care and 
some practice. On charcoal, with soda in the inner 
flame, it gives a gray metallic powder, attractable 
by the magnet. In the borax bead in the outer 
flame it gives a hyacinth-red to violet-brown while 
hot, a yellowish or yellow-red when cold. In the 
reducing or inner flame, a gray appearance is given. 
These appearances are modified by the impurities 
and the amount of nickel in the mineral. The wet 
process is the only method of determining the true 
value of a nickel-bearing mineral. 

Its chief ores are : 

Smaltite, which is a combination of cobalt, iron 
and nickel, and arsenic in varying proportions. It 
will be more fully referred to, later on, under 

Nickel arsenide, " copper nickel" mineralogical 
name, nicolite. Composition : nickel 44.1 ; arsenic 


55.9. It looks somewhat like pale copper, but con- 
tains no copper. Hardness 5-5.5, specific gravity, 
6.67-7.33 ; streak, pale brownish to black ; brittle. 
It frequently contains a little iron, and sometimes a 
trace of antimony, lead and cobalt. 

If carefully treated under the blow-pipe with 
borax, it will show the iron if present, in the bead, 
and the cobalt and nickel by successive oxidations 
(see under Smaltites later on). But the nickel re- 
quires especial treatment, the detection of which we 
will speak of in this chapter. 

There is another mineral, not properly an ore, 
called : 

Emerald-nickel, a carbonate of nickel, contain- 
ing 28.6 water when pure. It forms incrustations 
on other minerals, like another called 

Millebite, a sulphide of nickel forming tufts of 
very fine acicular, brassy-looking crystals, in cavities 
of the red hematite of Sterling Iron Mines in North- 
ern New York, and velvety incrustations on ores 
in Lancaster Co., Penna., where nickel was found and 
worked. In the former place no nickel abounds, 
but in the latter it has in the past been found in 
paying quantities. But the sulphides forms at the 
latter place vary very much, as examined under the 
microscope, from the acicular crystals found in the 
ores at Sterling, N. Y., and yet they are of the same 
chemical combination. The ore upon which the 
tufts of velvety covering are found at the Gap Mine, 
Lancaster Co., Penn., is pyrrhotite or sulphide of 
iron, holding 4 to 5.9 per cent, nickel in composi- 
tion ; that of Sterling, N. Y., is the red hematite. 

The sources of nickel discovered in Sudbury, 
Canada, north of Georgian Bay, yield nickel in 
pyrrhotite (sulphide of iron), and apparently also in 
chalcopyrite, whose typical composition is copper 
34.6, iron 30.5, sulphur 34.9. It is a mineral of 
brass-yellow appearance, and one which furnishes 
the copper of commerce at the Cornwall Mines 
(Eng.) and at the copper beds in Fahlun, Sweden. 
In the latter place it is imbedded, as it appears to 
be in the region of the Sudbury Mines, only that 
the Sudbury ore is imbedded in pyrrhotite and the 
Swedish in gneiss. 

The chalcopyrite does not mix intimately with 
the nickel ore so as to form a homogeneous mass ; 
it occurs by itself in pockets or threads, etc., but 
inclosed with massive pyrrhotite, which, while it 
may have more than 30 per cent, of nickel present, 
does not show any sign of the changed composition.* 

This per cent, is far above the average of nickel 
in the pyrrhotite, which seldom carries less than 2J 
per cent, or more than 9 per cent, of nickel. 

The following new ores of nickel are reported by 
Dr. Emmons from Sudbury, Canada : 

Foleyrite, of a bronze-yellow color, grayish-black 
streak, and metallic lustre. It occurs massive and 
contains 32.87 per cent, of nickel. Its specific 
gravity is 4.73, hardness 3.5. 

Whartonite contains 6.10 per cent, of nickel. It 
has a pale bronze-yellow color, black streak and 

* Dr. E. B. Peters, Manager of the Canada Copper Company. 


metallic lustre. Specific gravity about 3.73 ; hard- 
ness about 4. 

Jack's Tin or Blueite contains 3.5 per cent, of 
nickel. It is of an olive-gray to bronze color, me- 
tallic lustre and black streak. Specific gravity 4.2; 
hardness 3 to 3.5. 


As this analysis requires care, we give the follow- 
ing method in full : 

1. Keduce finely 50 grains of the ore. Put it in 
a dry beaker-glass and pour over it a mixture of one 
part sulphuric acid with three parts nitric acid, both 
pure and concentrated, or 40 to 50 c.c. to 2 grams 
of ore. 

2. Heat the covered beaker on a sand-bath to 
near 212° Fah. for two hours. Then partly un- 
cover, and evaporate the nitric acid entirely. 

3. Cool and add 100 or more c.c. of water and 
let it stand for four hours ; the insoluble residue is 
lead sulphate, silex, etc. 

4. Filter off the soluble part and place the moist 
lead sulphate in a beaker and dissolve it by first 
pouring in ammonia (20-25 c.c), and next acetic 
acid till it is decidedly acid. The sulphate now 
dissolves if kept warm for some twenty minutes. 
Filter and wash, and if any residue remains (silex, 
etc.), reserve for future examination. 

5. The lead 'is now separate, but if the amount 
is sought, pass a current of hydrogen sulphide 
through the solution till the lead is entirely pre- 


210 prospector's field-book and guide. 

cipitated. Filter, dry, place the residue in a porce- 
lain crucible and heat to a low-red heat, passing a 
current of dry hydrogen into the crucible while 
heating, to prevent any oxidizing of the sulphide. 
When the crucible and contents remain the same 
in weight, the last weight of the lead sulphide is the 
correct amount. Of this weight, 86.61 parts in 100 
are lead, 13.39 are sulphur. 

If the ore has no lead in it, the above work is 
omitted entirely. The likelihood of lead may be 
tested qualitatively from a small quantity dissolved, 
precipitated by hydrogen sulphide, and the precipi- 
tate determined by the blow-pipe on charcoal giving 
the lead coating, and with soda, the metallic globule. 

6. To separate the copper. The filtrate re- 
maining after the insoluble lead sulphate was fil- 
tered ofT, as in No. 4, now contains whatever the 
mineral is composed of, copper, iron, nickel, cobalt, 
etc. Dilute the filtrate to about 500 c.c, heat to 
nearly boiling, and pass hydrogen sulphide through 
it, and thus precipitate all the copper after adding 
1 or 2 c.c. of hydrochloric acid. Filter, wash, dry, 
and ignite the precipitate in an atmosphere of 
hydrogen. The result will be pure Cu 2 S, from 
which the copper may be ascertained as 79.85 parts 
of the whole weight of Cu 2 S. 

7. Concentrate by evaporation the filtrate of 
No. 6 remaining after the copper was separated, add 
1 or 2 c.c. of nitric acid, and boil the filtrate two 
or three minutes, let it become nearly cold, add an 
excess of ammonia, and let it stand in a warm place 
half an hour. 


8. Filter the precipitate into a porcelain dish and 
redissolve the iron oxide (hydroxide) with hydro- 
chloric acid poured slowly into the filter, complete 
washing of the filter with hot water, reduce the free 
acid in the filtrate with ammonia, then very nearly 
neutralize it carefully with sodium (metallic) or 
ammonium carbonate ; the solution must remain 
clear, though dark red, if much iron is present. 
Now add a strong neutral solution of ammonium or 
sodium acetate (not in large excess), and then boil 
a short time. When rightly performed the iron 
oxide precipitate will settle rapidly, and the super- 
natant liquor will be clear. Wash rapidly with 
boiling water, and, at first, separate the clear part 
by decantation, and then filter. If great exactitude 
is required, redissolve in hydrochloric acid, and 
once more precipitate with the acetate just as before. 
Add this filtrate to the ammoniacal filtrate men- 
tioned at the beginning of No. 7 paragraph. 

The iron is now separated as basic ferric acetate, 
and it is almost, if not entirely, separated from all 
nickel and cobalt which are yet in solution. 

9. The first filtrate, No. 7, contains all the nickel 
and cobalt. It must now be concentrated to about 
250 c.c. If it is slightly acid, proceed ; if not, then 
add muriatic acid until it is very slightly acid. 
Now heat the filtrate in a beaker to gentle boiling, 
and pass hydrogen sulphide through the liquid. A 
black precipitate follows ; if nickel sulphide with 
cobalt sulphide, they are together. 

10. Filter, wash, and dry ; incinerate the filter- 

212 prospector's field-book and guide. 

paper with the precipitate if very small in quantity, 
otherwise separately ; heat in porcelain crucible. 
Dissolve in aqua regia (nitro-muriatic acid), and 
treat it till only yellow sulphur remains, evaporate 
and expose the residue to a heat of 180° Fah. to 
make any silica insoluble. Moisten with a few 
drops of muriatic acid, add 20 c.c. of water to dis- 
solve the salts, add some solution of hydrogen sul- 
phide to separate any copper or lead which may 
have escaped separation, filter into a porcelain dish 
and concentrate all to about 100 c.c. 

11. Boil gently, and while boiling add pure so- 
dium carbonate solution until the liquid is slightly 
alkaline. Continue boiling a few minutes, add a 
few grains of pure soda solution (sodium hydroxide). 
This is best prepared freshly by dropping a small 
ball of metallic sodium into a half ounce of water 
in a platinum dish or crucible, or, not so well, in a 
porcelain dish. Heat to a boiling again a few min- 
utes till all the nickel and cobalt are precipitated, 
wash the precipitate with boiling hot water by de- 
cantation, and finally on the filter, until a drop on 
polished platinum shows no residue. After drying 
the precipitate remove it to a piece of glazed paper ; 
cover with a bell-glass. Then incinerate the filter 
till the carbon has entirely disappeared, add it to 
the precipitate already obtained, place all in a cru- 
cible, cover it and expose to heat to redness, and, 
finally, if desired, reduce the oxides to the metallic 
condition by ignition under a stream of hydrogen. 

12. As this process of reduction to metal is some- 



times very useful, we give a sample plan of appa- 
ratus for this purpose. Get a half-pint wide- 
mouthed pickle bottle and introduce two glass tubes 
of a quarter-inch diameter into a cork fitting the 
mouth, after having nicely adjusted the cork to the 
mouth of the bottle. The tubes may be easily bent 
and blown as in A B, Fig. 60, over the flame 
of an alcohol lamp, before permanently fastening 
them in place. To blow a funnel end, heat the end 

Fig. 60. 

of the tube to softness and mash it together, her- 
metically seal, then reheat rapidly, roll it between 
finger and thumb while gently blowing at the other 
end until swollen large enough, then, with pincers, 
break it or chip it off ; if enlarged twice or three 
times the diameter, it is large enough for the pur- 
pose. The tubes intended to be bent should be 
rapidly rotated in the enlarged flame until red-hot, 
and then bent to the right angle and gradually 


It is well to make another of these bottles for dry- 
ing the hydrogen, as in B. Introduce the tube as 
shown in the figure, wherein B represents the drying 
bottle in which is placed a quantity of fragments 
of chloride of calcium of the size of peas or even 
smaller. In putting the cork with tubes into this 
bottle, the bottle should be on its side and rolled 
while introducing the longer tube into the calcium 
chloride, so that the fragments may not obstruct 
the tube as it is pushed down. The exit tube may 
be bent or straight, and properly-sized india-rubber 
tubing may be fitted over the ends so as to make 
connections. A common clay stem smoking pipe 
arranged as in the figure, with the bowl inverted 
into the crucible which is placed on a wire support 
on a retort stand, c, is quite sufficient. The usual 
alcohol blast lamp, d, is necessary for this operation. 
To put the apparatus to work it is only necessary to 
introduce some three or four ounces of broken-up 
pieces of zinc into A, together with water sufficient 
to half fill the bottle, cork up with the tubes ar- 
ranged as above, and pour into the funnel-shaped 
tube common oil of vitriol gradually, until the gas 
begins to come over, then stop as the water becomes 
heated, and the gas will increase without addition. 
You may now prepare your crucible, and, when in 
place, and the tubes all arranged, the gas may be 
made to come over more rapidly by adding a little 
more oil of vitriol, drop by drop. 

13. The crucible should be weighed after cooling 
and replaced, the flame of the blast lamp relighted, 


and red heat renewed under the hydrogen apparatus 
until the crucible, when again weighed, shows no 
alteration in weight. The oxide has now been re- 
duced to the pure metal form, and it may then be 

In the case of the analysis we are now upon, the 
metallic reduction will be that of both nickel and 
cobalt, and they will appear as a dark powder in 
the bottom of the crucible. 

When the hydrogen apparatus is no longer to be 
used, the generator bottle A should be washed thor- 
oughly and the zinc also ; the latter may be left i n 
the bottle and the cork replaced loosely, but the 
cork must be removed from bottle B, and a tight- 
fitting cork be used in its place, as the chloride may 
be used again. All is ready for another operation 
by simply replacing and adding water and acid as 

14. Separation op Nickel and Cobalt. The 
two metals should be weighed in order that, if the 
cobalt be found, the nickel may be known by the 
difference. Dissolve the two metals in nitric acid 
and evaporate them till there is no free nitric acid. 
Next add about 6 to 8 grams (100 grains) potas- 
sium nitrate dissolved in 10 to 15 c.c. of hot water. 
If any flocculent particles appear, add a little 
acetic acid, just sufficient to dissolve them, and 
now a precipitate of cobalt (as tripotassium cobaltic 
nitrate), takes place slowly. The whole volume 
should now be 15 to 20 c.c. Cover the beaker con- 
taining it with glass, and set it aside in a warm 

216 prospector's field-book and guide. 

place for twenty-four hours. Filter, wash with a 
solution of potassium acetate (which may be made 
by neutralizing acetic acid with crystallized potas- 
sium bicarbonate, leaving the solution slightly 
acid), and proceed to more efficiently separate the 
cobalt as a metal, as follows : 

Dilute the filtrate, heat, and precipitate with 
caustic soda (sodium hydroxide), wash the greater 
part of the saline matter out and then dissolve the 
precipitate in nitric acid, evaporate to dryness, add 
two or three drops of nitric acid and dissolve in a 
small volume of water, filter, concentrate the fil- 
trate, and repeat the process of separation of potas- 
sium nitrate as before. Put this precipitate, with 
the filter-paper, into a beaker, add about 100 c.c. of 
water, heat, add muriatic acid to dissolve it, separate 
the filter-paper by filtering it and washing it in a 
funnel, evaporate the solution on a water-bath, and 
let it remain on the water-bath two or three hours 
to render the silica insoluble, then moisten with 
muriatic acid, add water, filter, and convert the co- 
balt to metallic form, as was done before for both 
nickel and cobalt, namely, as in paragraph No. 11. 
The cobalt is now entirely separate from the nickel. 
Weigh it, and by difference from the weight of the 
two determine the weight of nickel as suggested in 
No. 14. The amount of nickel is now known by 
weight, and readily compared with the whole 
amount of the original weight of ore employed at 
the beginning. 

If the above process is carefully followed out, in a 


mineral containing lead, copper, iron, cobalt, and 
nickel, the cobalt and nickel are separated with 
great exactness. 

But the main ore of nickel is pyrrhotite, and, as 
in the Gap Mine, Lancaster Co., Penn., and in the 
Sudbury Mines, Canada, pyrrhotite contains only 
iron and nickel, seldom cobalt enough to notice. 
So that much less work is required, as follows : Pul- 
verize, dissolve in muriatic acid in a flask. If 
much free acid is present, nearly neutralize with 
sodium or ammonium carbonate; the solution should 
be clear, but, if there is much ferric chloride, it 
should be of a deep-red color ; now do as directed in 
No. 8, to add the ammonium acetate, and proceed 
as before. 

In view of the importance of nickel-steel armor 
plates, prospecting for nickel is a work of unusual 
interest. In addition to the discovery of the nickel 
pyrrhotite in Canada, which we have already no- 
ticed, new discoveries have been reported from New 
Caledonia, an island 900 miles east of Australia. 
The ore is a nickel silicate and has been named 
Garnierite, after M. Gamier, its discoverer. It is 
also found in Oregon. It contains from 8 to 10 per 
cent, of nickel, has a green color and yields an un- 
colored streak. 

The mines at the Gap, Lancaster Co., Penn., are 
considered nearly, if not quite, exhausted. There is 
now, as may readily be imagined, increased demand 
for nickel ores. 

IV. Cobalt. — Cobalt does not occur in native 

218 prospector's field-book and guide. 

form. The following are the minerals of impor- 
tance : 

Smaltite seems to be composed of cobalt, nickel, 
iron and arsenic; the typical form is arsenic 72.1, 
cobalt 9.4, nickel 9.5, iron 9 = 100. Hardness 
5.5-6 ; specific gravity 6.4-7.2. Color, tin-white, 
sometimes iridescent. Streak, grayish-black. Brit- 
tle. Before the blow-pipe, on charcoal with soda, the 
arsenious acid fumes are given off, and the garlic 
smell is plainly observed. With borax for the bead 
the assay may be made to show (with successive 
heatings) the reactions, first of iron, then cobalt, and 
nickel, provided the operator is skillful in oxidizing 
the powdered ore by cautious degrees ; when one 
borax bead shows iron reaction by a certain amount 
of carefully applied F to the bead, try another 
w T ith increased degree of oxidation until you per- 
ceive the cobalt blue and nickel brown, if both are 

Cobaltite is composed of sulphur, arsenic, and 
cobalt in the typical proportions of 19.3, 45.2, 35.5 
= 100, but it frequently, as a mineral, contains iron. 
Hardness 5.5 ; specific gravity 6-6.3. Under the 
blow-pipe, in an open tube, it sends off sulphurous 
fumes and a sublimate of arsenious acid. With borax 
bead gives the blue of cobalt. Dissolves in warm 
nitric acid, separating the sulphur and arsenic. 

Cobaltite and smaltite are valuable as affording 
the greater part of smalt of commerce, and the for- 
mer is used in porcelain painting. 

Erythrite is a soft (1.5-2.5) peach-red mineral 


of specific gravity 2.9, transparent or translucent, 
sometimes pearl- or greenish-gray. 

Composition, typical, arsenic 38.43, cobalt oxide 
37.55, water 24.02 = 100. 

In a closed tube, under blow-pipe, it yields water 
and turns bluish. Gives the usual blue for cobalt 
in the borax bead. 

Valuable for the manufacture of smalt. It is 
sometimes knowm as " cobalt bloom" 

Linn^eite. This is valuable for the large amount 
of both cobalt and nickel it sometimes contains. 
Hardness 5.5 ; specific gravity 4.8-5; metallic lustre ; 
color, pale steel-gray, tarnishing to red. Composi- 
tion, sulphur 42, cobalt 58 == 100, but cobalt is re- 
placed by large amounts of nickel, and sometimes 
copper. Some specimens from Mineral Hill, Mary- 
land, and from Missouri, have yielded as high as 
29.56 and 30 per cent, nickel, with 21 to 25 per 
cent, cobalt in the same specimen, but with a small 
amount of iron (3 per cent.). 

Earthy Cobalt, or Cobalt Wad (Asbolite is the 
mineralogical name), occurs as a bog ore, with man- 
ganese, iron and copper, and nickel. It is blue 
black at times, has a hardness of 1 to 1.5, and 
specific gravity of 2.2 to 2.6. It sometimes contains 
up to 35 per cent, of cobalt oxide. 

The geological position of cobalt is in the earlier 
rocks, as the chlorite slates with chalcopyrite, blende, 
and pyrite, as in Maryland. Sometimes the ore is 
found in cavities in the limestone of the carbonifer- 
ous age, as in Great Britain. The tin-white cobalt 

is found in the gneissic and primitive rocks, as in 
Norway. Linnaeite is found at Mine la Motte, Mo., 
in masses, sometimes in octahedral crystals among 
its rich ores of lead and nickel. 

Cadmium. Of this mineral but one ore is known, 
namely, the sulphide, or Greenockite, with 77.7 
per cent, cadmium. Color, honey to orange-yellow 
and brick-red ; in hexagonal prisms ; hardness 3 to 
3.5 ; specific gravity 4.5 to 4.908. Before the blow- 
pipe, on charcoal with soda, it yields a red-brown 
deposit. Cadmium is frequently associated with 
zinc ores, some varieties of sphalerite or blende con- 
taining 3.4 per cent. 

Metallic cadmium is white like tin, and shares 
with it the property of emitting a crackling sound 
when bent. It is so soft that it leaves a mark upon 



I. Aluminium. The distribution of aluminium 
in nature is very wide, rivaliug that of iron, yet there 
are but few minerals which serve as sources of the 
metal. These are : Bauxite, a limonite, in which 
most of the iron is replaced by aluminium ; soft and 
granular, with 50 to 75 per cent, alumina. Corun- 
dum, crystalline and very hard, specific gravity 4, 
generally quite pure, but too valuable for abrasive 
purposes to be used as an ore. Diaspore, hard and 
crystalline, specific gravity 3.4, with 64 to 85 per 
cent, alumina, and ordinarily quite pure. Gibbsite, 
stalactic, specific gravity 2.4, containing, when pure, 
65 per cent, alumina. Aluminite, specific gravity 
1.66, a sulphate of aluminium found in large beds, 
chiefly along the Gila River, in New Mexico, con- 
taining about 30 per cent, alumina, and easily solu- 
ble in water. Cryolite, specific gravity 2.9, easily 
fusible, and when fused its specific gravity is about 
2. It contains 40 per cent, aluminium fluoride and 
60 per cent, sodium fluoride. All clays contain a 
large percentage of aluminium, but always in the 
state of silicate, and the difficulty of removing this 
silica has so far prevented the employment of clay 
as an ore of aluminium. 


222 prospector's field-book and guide. 

Of the ores above named the most important is 

Bauxite, of which there are vast deposits at 
Baux, near Aries, in France, in Ireland, and in 
Alabama, Arkansas, the Carolinas, Georgia, Tennes- 
see and Virginia. 

The Arkansas deposits are said to cover a large 
area, and to reach a thickness of 40 feet, forming 
an interbedded mass in ferruginous Tertiary sand- 

The Alabama deposits are better known, and all 
occur in the lower part of the lower Silurian forma- 
tion. The district has been badly broken up by 
sharp fold and great thrust faults, and the mineral 
occurs as pockets in close association with brown 
iron ore (limonite) and clay. 

Bauxite has to undergo purification for the pur- 
pose of the aluminium manufacturer. Several 
methods are used : 

1. It is chosen as free from iron as possible, and 
is roasted at a low red heat, and afterwards treated 
with sulphuric acid, which combines with the 
alumina present, forming sulphate of alumina. 
This is readily dissolved by water, leaving the great 
bulk of silica and iron behind. The solution of 
sulphate of alumina is allowed to settle, the super- 
natant liquid is siphoned off into an evaporating 
tank and evaporated to dryness. The dry sulphate 
of alumina is calcined at a red heat, driving off the 
sulphuric acid, leaving as a residue anhydrous 

2. The bauxite is treated either by fusing with 


carbonate of soda and dissolving in water, or by 
boiling it with a strong solution of caustic soda. 
In either case a solution of sodium aluminate is ob- 
tained, which is filtered from the residue of silica 
and ferric oxide, and decomposed into aluminium 
hydrate and carbonate of soda by pumping carbonic 
acid gas through it. After a thorough washing, the 
hydrate is calcined at a high heat, and the resulting 
alumina is finely ground. 

The ore next in importance is 

Cryolite, of which there is practically only one 
productive mine, that at Ivigtut, South Greenland. 
The mine is worked as a quarry, and has been 
opened 450 feet long, 150 feet wide and 100 feet 
deep, while diamond drills have proved the perma- 
nence of the ore for a further depth of 150 feet. The 
vein appears to widen with depth, but the quality 
of the mineral becomes inferior. About 10,000 
tons of cryolite annually are shipped to the United 

With the blow-pipe, on charcoal, cryolite fuses to a 
clear bead, becoming opaque on cooling. After long 
blowing with O F the assay spreads out, the fluoride 
of sodium sinks into the charcoal, and the suf- 
focating odor of fluorine is given off and the alumin- 
ium remains as a crust which, if touched with a 
little cobalt solution and gently heated, gives a blue 
color of alumina. If some of the cryolite is pow- 
dered and placed near the open end of a glass tube 
and the flame from the blow-pipe turned carefully 
on it, the fluorine will be freed and will etch the 


glass, showing corrosion and proving the presence 
of fluorine. Besides, as a source of the metal alu- 
minium, cryolite is used as a flux, and largely for 
the manufacture of alumina of soda. 

While the older processes of aluminium manu- 
facture, dependent on the reduction of the double 
chloride of aluminium and sodium, must always 
have a scientific interest, they have been beaten out 
of the field of commercial industry by the newer 
electrolytic methods, of which there are four varie- 
ties. In England and America Cowles' and Hall's 
patent are followed ; on the Continent, Heroult's 
and Minet's. They are all virtually modifications 
of the original Deville-Bunsen process, maintaining 
fusion by the heat of the electric current. 

Corundum and Emery. While corundum and 
emery are very nearly allied mineralogically, they 
are sharply distinguished in commerce. Corundum 
is almost a pure alumina, but emery is contaminated 
with a large proportion of iron oxide, ranging gen- 
erally between 20 and 33 per cent. Physically they 
are also distinguished by the following features : 
Corundum is variously colored, commonly gray, but 
never black. It is much harder than emery, with 
sharper edges, and cuts more deeply and rapidly. 
It is, however, more brittle, aud therefore less dur- 
able. Emery -is practically always black. 

Corundum is infusible before the blow-pipe, and 
is not affected by acids nor by heat. It crystallizes 
in six-sided prisms, often irregularly shaped and 
sometimes occurs in granular masses. Transparent 


or opaque. Lustre, glassy, sometimes pearly. 
Fracture uneven or conchoidal. Specific gravity, 
3.9 to 4.2. Hardness, 9, it being, next to diamond, 
the hardest of minerals. It is generally found 
associated with some member of the chlorite group, 
and a series of aluminous minerals in part pro- 
duced from its alteration. 

The blue variety of corundum is called Sapphire, 
the most esteemed shade being deep velvet blue ; 
the blood-red variety is the Oriental Ruby, which 
can be readily distinguished from other red gems 
by its superior hardness ; the bright yellow variety 
is the Oriental Topaz, distinguished by its hard- 
ness from the topaz, yellow tourmaline and false 
topaz ; the bright green is the Oriental Emerald ; 
the bright violet, Oriental Amethyst. One vari- 
ety exhibits a six-rayed star inside the prism, and 
is called the Asterias. Euby is the most highly 
prized form of this mineral. 

Corundum has been found in a large number of 
localities in the United States, but only a few places 
have been actual producers. The emery vein or 
bed at Chester, Mass., has furnished a large quan- 
tity of the mineral, but the chief American source 
at present is a belt of serpentine that extends from 
southwestern North Carolina into Georgia. It is an 
altered olivine rock, and has gneiss for its immedi- 
ate associate, and along the contact of the two are 
found the veins or beds of decomposed rock which 
have the corundum disseminated through them. 
Corundum Hill, in North Carolina, and Laurel 

226 prospector's field-book and guide. 

Creek, in Georgia, are the chief producers. The 
mineral is crushed, sifted and washed, and thus 
comes to market in various sizes. Care is taken to 
avoid making undue amounts of the finest product, 
or " flour," for this has less value than the coarser 

The chief European sources of emery are the 
Greek island of Naxos and Asiatic Turkey. 

The usual test for the quality of a sample of 
emery or corundum is to compare a weighed sample 
with an equal amount of the standard grade or of 
some well-recognized brand. Two weighed pieces 
of plate glass of convenient size are then rubbed to- 
gether with the sample between, and the process is 
continued until the grit has disappeared and the 
plates no longer lose in weight from the abrasion. 
The amount of loss is a measure of the hardness 
and abrading power of the sample, the better grade 
giving the greater loss. 

III. ANTIMONY. This metal occurs in three 
forms, namely, the oxide, senarmontite, containing 
83.56 per cent, antimony ; the sulphide, stibnite, 
antimonite or antimony glance, affording 71.8 per 
cent., a sulphoxide, kermesite, giving 75.72 per cent., 
in addition to some unimportant combinations with 
silver, etc. While it may be said that antimony is 
somewhat widely distributed in nature, yet, owing 
to cost and difficulties in extraction, only compara- 
tively few mines affording a rich ore can be profit- 
ably worked. Beyond the considerable quantities 
of oxide coming from Algiers and of kermesite from 


Tuscany, almost the entire output is in the form of 

Stibnite, which contains 78.8 per cent, antimony 
and 28.2 sulphur. Hardness, 2 ; specific gravity, 
4.5. Streak and color, lead grey inclining to steel 
grey, subject to blackish tarnish, sometimes irides- 
cent. Lustre, metallic ; sectile. Occurs in rhom- 
bic, generally in radiated or divergent bunches ; 
massive with columnar or fibrous structure. Sol- 
uble in hydrochloric acid giving a slight crystalline 
precipitate of lead chloride if lead be present. 

Before the blow-pipe, on charcoal, it fuses, spreads 
out, gives sulphurous and antimonious fumes, coats 
the charcoal with white oxide of antimony ; this 
coat, treated in R F, tinges the flame greenish blue. 

Foremost in antimony production stands Portu- 
gal, due principally to the mining district of Oporto. 
The geological formations of Portugal are chiefly 
igneous and old sedimentary. The most favorable 
rocks for good antimony ore are bluish gray argil- 
laceous Silurian shales. 

Among the other European centers of production, 
the Bohemian mines are in granite and mica schist ; 
the Hungarian in granite — sometimes auriferous ; 
the Styrian in dolomite, and the Turkish also in 
granite. Victoria, New South Wales, and Western 
Australia are large producers of auriferous stibnite. 
In New Brunswick, antimony is mined in a quartz 
and calcite gangue in clay-slates and sandstones of 
Cambro-Silurian age. 

Within the United States stibnite has been found 
in a number of places, all in the West. At San 

228 prospector's field-book and guide. 

Emigdio, Kern Co., California, it is contained, with 
quartz gangue, in a vein in granite. The vein 
varies in thickness from a few inches to several feet. 
Several other small deposits occur in San Benito 
Co. and elsewhere in California. Stibnite has also 
been discovered in Humboldt Co., Nevada, and in 
Louder Co., not far from Austin, in a quartz gangue. 
Some remarkable deposits occur in Iron County, 
Utah, as masses of radiating needles, which follow 
the stratification planes of sandstone and fill the 
interstices of a conglomerate. Stibnite is found in 
Sevier Co., Arkansas, filling veins, with a quartz 
gangue, in sandstone. 

MANGANESE. The ores of manganese are 
divided into three general classes : 

1. Manganese ores. 

2. Manganiferous iron ores. 

3. Argentiferous manganese ores. 

Wad is the name given to manganese oxide. It 
is found in earthy compact masses of a dark brown 
color, chiefly oxide of manganese and water. 

Easily recognized under the blow-pipe, as it gives 
(in minute quantities), in the borax bead, a violet 
color in the F, but disappears when the R F is 
turned upon it, and reappears when the F is 

It is found in beds varying from several inches to 
a foot or more in thickness. Hardness 1 to 3 ; spe- 
cific gravity 2.3 to 3.7. Wad is used as a flux in 
iron smelting, and in a lixiviated state as a paint. 

Pyrolusite. This is the peroxide or dioxide, 


with 63.2 per cent, of manganese and 36.8 per cent, 
oxygen. Its crystalline form is the rhombic prism 
and it generally occurs in the form of minute crys- 
tals grouped together and radiating from a common 
centre. It has an iron-black or steel-gray color, a 
semi-metallic lustre and yields a black streak. 
Specific gravity 4.7 to 5 ; hardness 1.5 to 2.5 ; in- 
fusible before the blow-pipe, and acquires a red- 
brown color. On heating it generally yields some 
water and loses 12 per cent, of oxygen. With 
borax, soda and microcosmic salt it shows man- 
ganese reaction. It dissolves in hydrochloric acid, 
when heated, with vigorous evolution of hydrogen. 

Psilomelane occurs massive, frequently shelly, 
seldom fibrous; color, iron-black to bluish-black, 
streak bluish-black and shining ; fracture, con- 
choidal to smooth. Specific gravity 4.1 to 4.2, 
hardness 5,5 to 6. Before the blow-pipe it yields 
manganic oxide, giving off oxygen. It is soluble 
in hydrochloric acid, chlorine being evolved. The 
powdered ore colors sulphuric acid red. Psilome- 
lane contains from 40 to 50 per cent, of manganese, 
and some baryta and potassa. A solution in hydro- 
chloric acid of the variety containing baryta gives 
a heavy white precipitate with sulphuric acid. 

Rhodocrosite or Manganese Carbonate oc- 
curs in spherical and nodular aggregations of 
cauliform texture or in compact masses of granu- 
lar texture. It is rose-red to raspberry-red in 
color, by weathering frequently brownish, with 
a glassy or mother-of-pearl lustre. It cleaves like 

230 prospector's field-book and guide. 

calcite. It contains 61.4 per cent, of manganese 
protoxide and 38.6 per cent, of carbonic acid, 
with part of manganese frequently replaced by cal- 
cium, magnesium, or iron. Specific gravity 3.3 
to 3.6 ; hardness 3.5 to 4.5. Before the blow-pipe 
it is infusible and becomes black. From simi- 
lar minerals it is distinguished by its rose-color and 
the manganese reaction with soda and borax ; and 
from silicate of manganese by its inferior hardness, 
its effervescence with acids and its non-fusibility. 

The manganese in ores of the third class is valu- 
able, even where the silver alone is sought, as it 
facilitates the work whereby the silver is extracted; 
this it does because of its fluxing quality. 

Virginia, Georgia and Arkansas are the chief pro- 
ducing States. 

The geological position of manganese in some 
places seems to be the same as with the red hema- 
tite, as in Virginia. 

In Tennessee it is found in the foot-hills of the 
mountains, four miles from Newport, Cocke Co., in 
pockets, and is a black oxide of 48 per cent, metal- 
lic manganese. 

In Vermont it is found near a siliceous limestone, 
and in the vicinity of brown hematite ores. It ex- 
ists in the triassic formation in Bosnia. 

In North Carolina it is found in light-colored 
gneissic schists. 



Alum. This name is applied to a group of min- 
erals which are hydrous sulphates of aluminium 
with potash, soda, ammonia, magnesia, etc. They 
all crystallize in the regular system, are soluble in 
water and have an astringent sweetish taste. Hard- 
ness, 2 to 2.5 ; specific gravity, 1.8. Potash alum 
is the most common, and is usually found in the 
form of an efflorescence or an incrustation, with a 
mealy and sometimes a fibrous structure. It is 
abundant in clays, argillaceous schists, which, when 
largely impregnated with alum, are called alumi- 
nous schists or shales. 

Soda alum has a general resemblance to potash 
alum but is rather more soluble in water. Magnesia 
alum occurs in silky-lustred fibrous masses. Iron 
alum forms yellowish- white silky masses. 

It differs somewhat from the other alums in turn- 
ing red when heated. Alum is used in dyeing and 
calico printing, candle making, dressing skins, clari- 
fying liquids, and in pharmacy. 

Apatite, Phosphate of Lime, occurs in six-sided 
prisms, also in masses. It is transparent or opaque ; 
colorless, white, yellowish, green, violet, with a 

232 prospector's field-book and guide. 

glassy lustre, and yields always a white streak. 
Fracture, conchoidal or uneven. Specific gravity 
3.16 to 3.22 ; hardness 5. In thin laminae it is 
fusible with difficulty before the blow-pipe ; when 
moistened with sulphuric acid, tinges the flame 
greenish. It is soluble in hydrochloric and nitric 
acids without effervescence. From beryl it is dis- 
tinguished by its inferior hardness and its solubility 
in acids. It occurs in rocks of various kinds, but 
more frequently in those of a metamorphic crystal- 
line character, as in Laurentian gneiss, which is 
usually hornblendic, granitic or quartzose in char- 
acter, in Canada, and in association with granular 
limestone. It is also found as an accessory mineral 
in metalliferous veins, especially those of tin, and 
beautifully crystallized and of various colors in 
many eruptive rocks. It also occurs in veins by 
itself, mostly in limestone, but sometimes in gran- 
ites and schists. In these deposits apatite is also 
found as concretions, sometimes showing a radiated 
structure, but of an earthy appearance externally. 
In sedimentary formations where a considerable 
accumulation of fossils has provided the phosphate 
of lime it occurs in two principal forms, namely 
coprolites, which are excreta of large animals, 
especially saurians, and concretions formed at the 
expense of the same coprolites, together with shells, 
bones, etc. The richest of these deposits are from 
Lower Cretaceous to Lower Jurassic in age, but 
phosphatic deposits are found and worked in sedi- 
mentary deposits of all ages. 


The principal use of apatite is as a source of phos- 
phoric acid and phosphorus, and before the dis- 
covery of the phosphate-rock deposits in Florida 
was largely sold to the manufacturers of fertilizers. 

Arsenic is found in the mineral kingdom partly 
in a metallic state, partly in combination with 
oxygen, sulphur and other bodies. 

1. Native Arsenic occurs seldom distinctly crystal- 
lized, but usually in fine granular, spherical or 
nodular masses. Specific gravity 5.7 to 5.8 ; hard- 
ness 3.5 ; brittle ; uneven and fine-grained fracture ; 
metallic lustre ; color, whitish lead-gray, usually 
with a grayish-black tarnish ; evolves an odor 
of garlic on breaking ; contains occasionally more 
or less iron, cobalt, nickel, antimony and silver. 

Before the blow-pipe it quickly volatilizes before 
fusing, giving off white fumes having an odor 
of garlic. Native arsenic occurs especially in veins 
in crystalline slates and transition rocks in sub- 
ordinate quantities associated with ores of silver, 
lead, cobalt and nickel. 

2. Realgar, with 70.029 per cent, of arsenic and 
29.971 per cent, sulphur. Color, red ; crystallizes 
clinorhombic ; fracture conchoidal to splintery ; 
hardness 1.5 to 2.0 ; specific gravity 3.4 to 3.6. It 
it but slightly affected by acids ; soluble with a de- 
posit of sulphur in aqua regia, and in concentrated 
potash lye with separation of dark brown sulphuret 
of arsenic. From ruby silver and cinnabar, it is 
readily distinguished by its inferior hardness, 
slighter specific gravity and orange-yellow streak, 

234 prospector's field-book and guide, 

the streak of the two above-mentioned minerals 
being cochineal-red. 

3. Orpiment, with 69.9 per cent, of arsenic and 
39.1 per cent, of sulphur ; occurs in nature, but for 
industrial purposes is mostly artificially prepared. 
The mineral has a lustrous lemon-yellow or orange- 
yellow color, is cleavable into thin, flexible, trans- 
parent laminae ; hardness 1.5 to 2 ; specific gravity 
3.4 to 3.5 ; soluble in nitric acid, potash lye and 

Asbestus. Fibrous. Color, green or white. The 
asbestus of commerce is practically a finely fibrous 
form of serpentine, that is to say, it is essentially a 
hydrated magnesium silicate. Every deposit of ser- 
pentine is a possible repository of asbestus. It 
occurs in seams half an inch to several inches in 
width, running parallel to or crossing one another, 
the width of each seam making the length of the 
fibre. Canada furnishes at present a large portion 
of the world's supply of asbestus. The profitable 
mining, however, is at present confined to a small 
area in the great serpentine belt of the Province of 
Quebec, that lies to the south of the St. Lawrence 
River. In the form of a rough cloth asbestus is 
used for covering steam-pipes, and for many pur- 
poses requiring an incombustible material. 

Barytes, or barium sulphate, commonly called 
heavy spar, occurs in tabular, glassy crystals, and 
also in dull masses in veins of various rock forma- 
tions. Color, white or tinted ; transparent or trans- 
lucent ; lustre, vitreous or pearly. Specific gravity, 


4.3 to 4.7. Hardness, 3 to 3.5. It is readily dis- 
tinguished by its great comparative weight. When 
heated in the blow-pipe flame splinters fly off the 
crystals. It fuses with difficulty, and imparts a 
green tinge to the flame. After fusion with soda, it 
stains a silver coin black. It is not acted upon by 

In the United States barytes is found in many 
places, it being mined in Virginia, Missouri, New 
Jersey and other states. It frequently occurs in 
connection with lead and zinc deposits forming the 
gangue of the metal-bearing vein. The best varie- 
ties of barytes are the white and gray. The chief 
use of barytes is as a pigment, as a cheaper substi- 
tute for white lead. It is also used as a make- 
weight by paper manufacturers, etc. 

The carbonate of barium, with&rite, is a much less 
common mineral than the sulphate. It sometimes 
occurs in crystals, but the more common form is 
that in fibrous masses. It occurs in veins. It 
fuses easily in the forceps, and gives a yellow-green 
flame. In hydrochloric acid it dissolves with effer- 
vescence, the solution yielding a heavy white pre- 
cipitate (barium sulphate) if a little sulphuric acid 
is added. Witherite is used in the refining of 
sugar, and also in the manufacture of plate glass. 

Borax. Monoclinic. Fracture, conchoidal. Lus- 
tre, vitreous to resinous. Color, white, sometimes 
grayish, bluish, or greenish. Streak, white. Taste, 
slightly alkaline and sweetish. Translucent to 
opaque. Principal producing localities in the 

236 prospector's field-book and guide. 

United States : the Columbus and Rhodes marshes 
in Nevada, the Saline marshes in California. In 
the Calico district the borate of lime is taken from 
a fissure vein, and this district is the only place in 
the world where deep mining for borax is carried on. 

Borax is used in medicine and as an antiseptic 
by meat packers and others. Its chief use, how- 
ever, is as a flux in metallurgical operations, in 
enameling, glazing of pottery and in the manu- 
facture of glass. 

Clays. The clays are all products of alteration 
from other minerals. Their composition is variable 
and they do not crystallize. The true clays are all 
plastic and refractory to a greater or less degree, 
and on these properties their value for industrial 
purposes depends. Pure kaolin is the type of all 
the clays. 

The presence of alkalies in clays is objectionable, 
as it renders them fusible, as also do many other 
oxides. Iron is not only objectionable on the score 
of fusibility, but also as coloring matter. The 
presence of too large a proportion of water, carbonic 
acid or organic matter, causes clay to contract 
under the action of fire, and the same result will 
ensue if the clay is partially fusible. 

The soft clays are divided as follows : 

Kaolin, porcelain clay or China clay. This is a 
product of decomposition of feldspar and other min- 
erals, and never occurs in any crystalline form. Its 
composition varies somewhat according to the source 
from which it has been derived. In all cases it is a 


hydrated silicate of alumina, and its usual source is 
feldspar. It is a friable, soft substance of a white 
yellow, or flesh-red color, and capable of resisting 
the highest heat of a porcelain furnace. It usually 
contains more or less silica in an uncombined state. 
Its specific gravity is 2.2. Kaolin is almost entirely 
from the older feld spathic rocks, while clays are 
generally derived from younger rocks. 

Pottery or plastic clay is not so pure as Kaolin con- 
taining a large percentage of iron. 

Bole is a hydrated silicate of alumina and iron, 
of a somewhat variable composition, but generally 
containing about 42 per cent, of silica and 24 per 
cent, of water. It also contains a large amount of 
ferric oxide, which gives it its yellow-red or brown- 
ish-black color. It is soft and greasy, translucent 
or opaque, adheres to the tongue, and falls to pieces 
with a crackling noise when immersed in water. 
The hardness is 1.5 and the specific gravity 1.4 to 
2. It fuses with facility into a greenish enamel. 

Fuller's earth is a kind of clay composed, when 
pure, of 45 per cent, silica, 20 to 25 per cent, alum- 
ina, and water. It was formerly largely used as an 
absorbent in fulling or freeing woolen fabrics and 
cloth from fatty matters, but in modern times other 
substances have been substituted, and the consump- 
tion of it has greatly fallen off. 

Coal (Mineral). Massive, uncrystalline. Color, 
black or brown ; opaque. Brittle or imperfectly 
sectile. Hardness 0.5 to 2.5. Specific gravity 1.2 
to 1.80. Coal is composed of carbon with some 

oxygen and hydrogen, more or less moisture, and 
traces also of nitrogen, besides some earthy material 
which constitutes the ash. 

Anthracite {Glance coal, Stone coal). Lustre high, 
not resinous, sometimes submetallic. Color, gray- 
black. Hardness 2 to 2.5. Specific gravity, if pure, 
1.57 to 1.67. Fracture often conchoidal. Good 
anthracite contains 78 to 88 per cent, of fixed 

Bituminous coal. Color, black. Lustre, usually 
somewhat resinous. Hardness 1.5 to 2 ; specific 
gravity 1.2 to 1.4. Contains usually 75 to 85 per 
cent, of carbon. 

Cannel coal. Very compact and even in texture, 
with little lustre, and fracture largely conchoidal. 

Brown coal (often called lignite). Color, black to 
brownish-black. Contains 52 to 65 per cent, of 
fixed carbon. 

Jet resembles cannel coal, but is harder, of a 
deeper black and higher lustre. It takes a brilliant 
polish and is set in jewelry. 

Dolomite is composed of carbonic acid, lime, 
magnesia. It occurs in rhombohedrons, faces often 
curved. It is frequently granular or massive; 
white or dull tinted ; and glassy or pearly. Specific 
gravity 2.8 to 2.9 ; hardness 3.5 to 4. Effervesces 
in nitric acid and dissolves more slowly than calc 
spar. Yields quicklime when burnt. Occurs in 
extensive beds of various ages like limestone. It is 
used as a building-stone and in the manufacture 
of Epsom salts. It is difficult to distinguish from 
calcite without chemical analysis. 


Feldspar, Orthoclase, is composed of silica 
64.20, alumina 18.40, potash or soda (lime) 16.95. 
Crystallized or in irregular masses. Opaque ; 
usually flesh-red or white, or of various dull tints. 
Lustre, glassy or pearly ; fracture, irregular, but in 
some directions it splits with an even, glimmering 
cleavage face. Specific gravity, 2.3 to 2.8 ; hardness 
6. Before the blow-pipe it fuses with difficulty ; is 
not touched by acids. Where found in sufficient 
quantity to be of industrial value, it is usually ob- 
tained from veins in granite or pegmatite. The 
minerals associated with feldspar are chiefly quartz 
and mica, while tourmaline and topaz also occur 
commonly. Feldspar is, to a limited extent, em- 
ployed in the manufacture of glass, but the chief 
use for it is as a china glaze and as a glass-forming 
ingredient in the body of the porcelains. 

One of the finest varieties of feldspar is that 
known as Adularia, from Mount Adula, near, the St. 
Gothard Pass, where it is found redeposited from 
the rock mass in veins and cavities. It consists of 
silica 64, alumina 20, lime 2, and potash 14. Moon- 
stone is another variety, with bluish- white spots of a 
pearly lustre. Sunstone is another, with a pale yel- 
low color with minute scales of mica. Aventurine, 
feldspar sprinkled with iridescent spots from the 
presence of minute particles of titanium or iron. 
The last three varieties are employed as gem-stones, 
being occasionally set in brooches, but are too soft 
for rings. 

A beautiful variety of orthoclase known as Ama~ 

240 prospector's field-book and guide. 

zon stone occurs in large green crystals near Pike's 
Peak, in Colorado, in Siberia and elsewhere. 

Flint consists of silica, which in a very fine con- 
dition has been separated from the surrounding 
rock, and which, attracted to some organic or inor- 
ganic nucleus, and sometimes only to itself, has 
grown in successive layers or bands, often of different 
colors. Hornstone or chert is allied to flint, but it is 
more brittle and it takes its color — dirty grey, red, 
and reddish-yellow, green or brown — from the rocks 
in which it is found. It occurs in portions of sand- 
stone rocks usually containing a little lime, the fine 
silica being seemingly collected into one spot. 

Fluorspar, Fluorite, consists of 48.7 per cent, 
of fluorine and 51.3 per cent, of calcium. It occurs 
in cubes or octahedrons, and also in masses. It is 
transparent or opaque ; white or light violet, blue, 
green or yellow ; sometimes layers of different tints 
in the same piece. Lustre, glassy. It breaks with 
smooth cleavage planes parallel to the octahedral 
faces. Specific gravity 3 to 3.2 ; hardness 4. Be- 
fore the blow-pipe it is fusible with difficulty to an 
enamel. It is used in the manufacture of hydro- 
fluoric acid, with which glass is etched, and also as 
a flux for copper and other ores. Sometimes it is 
employed for ornaments, especially massive pieces, 
they taking a high polish. It occurs in veins with 
lead and silver ores. 

Graphite, Plumbago, Blacklead, consists es- 
sentially of carbon, in mechanical admixture with 
varying proportions of silicious matter, as clay, sand 


or limestone. It occurs in hexagonal crystals, but 
usually in foliated or massive layers. Color, steel 
gray to bluish black. Hardness very slight, 0.5 to 
1. Soils the fingers, makes a mark upon paper, and 
feels greasy. The specific gravities of different 
kinds of graphite vary according to the content of 
foreign admixtures, but lie within the limits of 
2.105 and 2.5857. Graphite is not affected by acids 
and strongly resists other chemical agents. It is 
largely used in the manufacture of pencils, crucibles, 
stove polish, and lubricants for heavy machinery. 
It is found in various parts of the world, chiefly in 
crystalline limestone, in gneiss and mica schists, 
frequently replacing the mica in the latter so that 
they become actual graphite schists. The chief 
source whence the bulk of the mineral has for 
many years been derived is the Island of Ceylon. 
In the United States graphite is obtained from a 
mountain, locally known as the Blacklead Moun- 
tain, which rises close to the village of Ticonderoga, 
Essex Co.,- New York. The graphite beds are 
interstratified between gneissic rocks. The beds 
dip at an angle of 45°. The ore in them is chiefly 
of the foliated variety, and is mixed with gneiss 
and quartz in the beds in veins or layers from 1 to 
8 inches in thickness, some of the deposits being 
richer than others. One of these has been followed 
to a depth of 350 feet. It is found of varying thick- 
ness and it opens out at times into pockets. 

Graphite is said to occur in great purity in 
different localities in Albany Co., Wyoming, in 

242 prospector's field-book and guide. 

veins from 1 foot 6 inches to 5 feet thick. At 
Pilkin, Gunnison Co., it occurs massive in beds 2 
feet thick, but of impure quality. It is also found 
in the coal measures of New Mexico, in Nevada, in 
Utah, and in the Black Hills of South Dakota. 

The value of graphite depends upon the amount 
of its carbon. To test the purity of graphite, pul- 
verize and then dry at about 350° F. 20 grains 
of it ; then place it in a tube of hard glass 4 to 5 
inches long, half an inch wide, and closed on one 
end. Add twenty times as much dried oxide 
of lead and mix intimately. Weigh the tube and 
contents, and afterwards heat before the blow-pipe 
until the contents are completely fused and no 
longer evolve gases. Ten minutes will suffice for 
this. Allow the tube to cool, and weigh it. The 
loss in weight is carbonic acid. For every 28 parts 
of loss there must have been 12 of carbon. 

Gypsum is a hydrous sulphate of lime, and is 
composed of sulphuric acid, lime and water. It 
occurs in prisms with oblique terminations, some- 
times resembling an arrow-head. It is transparent 
or opaque, white or dull tinted, with a glassy, 
pearly or satin lustre. Cleavage occurs easily in 
one direction ; specific gravity 2.3 ; hardness 2 ; can 
be readily cut with the knife. In the blow-pipe 
flame it becomes white and opaque without fusing, 
and can then be easily crumbled between the 
fingers. Nitric acid does not cause effervescence. 
It occurs .in fissures and in stratified rocks, often 
forming extensive beds. When pure white it is 


called Alabaster ; when transparent, Selenite ; 
and when fibrous, Satin Spar. When burnt, 
gypsum loses its water and falls to powder. This 
powder, called Plaster of Paris, which is per- 
fectly white when free from iron, possesses the 
property of reabsorbing the water lost, and in a 
very short time of assuming again the solid state, 
expanding slightly is so doing. It is this last 
property that renders plaster of Paris so valuable 
for obtaining casts. It is also used as a fertilizer. 

Infusorial Earth is an earthy, sometimes 
chalk-like siliceous material, entirely or largely 
made up of the microscopic shells of the minute 
organisms called diatoms. It occurs in beds some- 
times of great extent, sometimes beneath peat beds, 
and is obtained for commerce in Maine, New 
Hampshire, Massachusetts, Virginia, California, 
Nevada, Missouri. It feels harsh between the fin- 
gers and is of a white or grayish color, but often 
discolored by various impurities. Infusorial earth 
is used as a polishing powder, electro-silicon being 
the trade-name of one kind much used for polishing 
silver. It is also used for making soda silicate and 
for purposes of a cement. Being a bad conductor 
of heat, it is applied as a protection to steam boilers 
and pipes. It is also employed for filling soap. 

Lithographic Limestone. The only stone yet 
found possessing the necessary qualifications for 
lithographic work is a fine-grained homogeneous 
limestone, breaking with an imperfect shell-like or 
conchoidal fracture, and, as a rule, of a gray, drab 


or yellowish color. A good stone must be suffi- 
ciently porous to absorb the greasy compound 
which holds the ink, soft enough to work readily 
under the engraver's tool, yet not too soft, and must 
be firm in texture throughout and entirely free from 
all veins and inequalities. The best stone, and in- 
deed the only one which has yet been found to fill 
satisfactorily all these requirements, occurs at Solen- 
hofen, Bavaria. These beds are of Upper Jurassic 
age, and form a mass of some eighty feet in thick- 
ness. The prevailing tints of the stone are yellow- 
ish or drab. 

In the United States materials partaking of the 
nature of lithographic stone have been reported 
from various localities, but it is believed all have 
failed as a source of supply of the commercial arti- 
cle, though it is possible that ignorance as to the 
proper methods of quarrying may in some cases 
have been a cause of failure. 

Meerschaum or Sepiolite is a manganese sili- 
cate. When pure, it is very light ; and, when dry, 
it will float upon water. It will be recognized by 
its property, when dry, of adhering to the tongue, 
and by its smooth, compact texture. It is generally 
found in serpentine, in which rock it occurs in nod- 
ular masses ; but it is also found in limestones of 
tertiary age. It is of a snowy-white color and a 
useful substance when found in quantity, being 
much employed for the bowls of tobacco pipes, and 
for this purpose is mined in Asia Minor. 

Micas. These are silicates of alumina with pot- 


ash, rarely soda or lithia, also magnesia, iron and 
some other elements. Always crystallized in thin 
plates, which may be split into extremely thin flex- 
ible layers. Transparent in thin layers. Color, 
white, green, brown to black. Specific gravity 2.7 
to 3.1. Hardness 2 to 2.5 ; very easily scratched 
with a knife. Before the blow-pipe it whitens, but 
is infusible except on thin edges. When it can be 
obtained in large sheets, mica is very valuable. It 
is sometimes used in the place of window glass on 
board ship, for stoves and for chimneys for lamps. 
The ground material is used as a lubricant and in 
making ornamental and fire-proof paint. 

Biotite, or black mica, contains more magnesia 
than alumina. It is often present in eruptive rocks, 
especially some granites. Muscovite, or white mica, 
on the contrary, contains more alumina than mag- 
nesia, and as it also contains potash in small but 
appreciable quantities, it is sometimes called potash 
mica, and biotite magnesian mica. Muscovite is an 
important mineral to the tin miner, since it is 
always found in that class of granite in which tin- 
stone occurs, and with quartz alone forms the rock 
called greisen, which is very generally associated 
with tin. The rock in which large sheets of mica 
are found is called by some geologists pegmatite, and 
has the same composition as granite itself, but the 
crystals are of a larger size. 

Molybdenum. The sulphide occurs native as 
Molybdenite in crystallolaminar masses or tabular 
crystals, having a strong metallic lustre and lead- 

246 prospector's field-book and guide. 

gray color, and forming a greenish-black streak 
which is best seen by drawing a piece across a china 
plate. Specific gravity 4.5 to 4.6 ; hardness 1 to 
1.5 ; easily scratched by the nail. It contains 58.9 
of molybdenum and 41.1 per cent, of sulphur. It 
occurs sparingly in granite, syenite and chlorite 
schists, and is sometimes mistaken for graphite, from 
which it is, however, readily distinguished by the 
streak, that of graphite being black. Before the 
blow-pipe it is infusible, but tinges the flame faint 
green. Heated on charcoal for a long time it gives 
off a faint sulphurous odor and becomes encrusted 
white. Its chief use is in the preparation of a blue 

Nitre or Saltpetre is white, inodorous, not de- 
liquescent ; at a red heat it is decomposed with evo- 
lution first of oxygen. It has a cooling saline taste, 
a vitreous lustre, a hardness of 2, and specific grav- 
ity of 1.9. It is usually found native as an efflo- 
rescence on the soil. It is constantly forming in the 
neighborhood of decomposing organic matter, espe- 
cially in stables and certain caves, such as those in 
Ceylon, America and elsewhere, which are inhab- 
ited by a large number of bats. It is distributed 
through many limestones and soils. 

Rock Salt has the character of ordinary table 
salt, but is more or less impure. Occurs in beds 
interstratified with sandstones and clays, which are 
usually of a red color and associated with gypsum. 
Specific gravity 2 to 2.25 ; hardness 2 to 2.5. It 
contains 39.30 per cent, of sodium and 60.66 per 


cent, of chlorine, but most samples contain clay and 
a little lime and magnesia. The surface indications 
of rock salt are brine springs supporting a vegeta- 
tion like that near the sea coast, also occasional 
sinking of the soil caused by the removal of the 
subterranean bed of salt by spring water. Rock 
salt is obtained by sinking wells from which the 
brine is pumped and evaporated in large pans, or 
by mining, the same as for any other ore. 

Salt deposits occur in the strata of all ages, from 
the Silurian to those now forming. In North 
America a chain of mountains extends along the 
west bank of the river Missouri for a length of 80 
miles by 45 in breadth, and of considerable height. 
These mountains consist largely of rock salt. The 
same formation extends into Kentucky, where the 
deposits are called " licks," because of the licking 
of the rocks and soil by the herds of wild cattle 
that once roamed there. In Michigan, in the 
neighborhood of Marine City, a well was sunk to a 
depth of 1,633 feet, when a deposit of rock salt was 
entered and penetrated to a depth of over 1,500 feet 
without the tools passing through it. The deposit 
seems to increase in thickness, but it is reached at 
an increasing depth as it trends in a south-westerly 
direction by Inverhuron, Kincardine, and War- 

An extraordinary superficial deposit of rock salt 
occurs in Petite Anse Island, parish Iberia, Lou- 
isiana. The island is about two miles in diameter, 
and the salt deposit on it is known to extend 

248 prospector's field-book and guide. 

under 165 acres. It is covered with 16 feet of soil. 
It has been proved to a depth of 80 feet. The salt 
occurs in solid masses of pure crystals, and it is 
taken out by blasting. 

The bulk of the manufactured salt in North 
America is obtained from brine springs. Valuable 
and productive springs are worked in Syracuse and 
Salina districts, New York, and in Ohio. Some of 
these arise from a red sandstone whose geological 
place is said to be below the coal measures. 

Rock salt has been discovered in Nevada. The 
southern termination of the deposits is about seven 
miles from the uppermost limit to the navigation of 
the Colorado river. Some of the specimens are 
sufficiently pure and transparent to allow of small 
print being read through them. In the same state 
there is an interesting salt lake, the water of which 
contains about two pounds of salt and soda to every 
gallon. It is several hundred feet deep. Soda and 
salt have been obtained from this lake for sev- 
eral years by natural evaporation. The water is 
pumped into tanks at the beginning of the summer 
season. It is left in these tanks during the warm 
summer months until the frost sets in. When the 
first frost comes the soda is precipitated in crystals. 
The water is then drained off into a large poncl, 
where slow evaporation goes on, and a deposit of 
common salt is obtained. 

The famous salt mine of Wieliezka, near Cracow, 
in Galicia, has been worked since the year 1251, 
and it has still vast reserves of the mineral. 


Slate is an argillaceous shale easily recognized 
by its cleavability, and varies in color from light 
sea-green and gray to red, purple and black. It has 
been formed by sedimentary deposits, and now con- 
stitutes extensive beds in the Silurian formation. 

Sulphur. Native sulphur or brimstone occurs 
crystallized or massive in volcanic regions and in 
beds of gypsum. Color, yellow ; lustre, resinous ; 
specific gravity 2.1 ; hardness 1.5 to 2.5. It is 
fusible and burns with a blue flame and well-known 
odor. It is frequently found contaminated with 
clay or pitch. Italy and Sicily together furnish 
the greater part of the sulphur of commerce, the 
major portion coming from Sicily. The most im- 
portant deposits of brimstone in the United States 
are found in Utah at Cove Creek, 22 miles from 
Beaver, while there are other deposits at a point 
about 12 miles southwest from Frisco. Large de- 
posits of sulphur are know T n to exist in Wyoming, 
California and Arizona, but none of them is at 
present available for working at a profit. 

A scarcity of brimstone has led to greater atten- 
tion being paid to native pyrites, especially for the 
manufacture of sulphuric acid. While there are 
many deposits of iron pyrites in most parts of the 
world, they are not always accessible to mining at 
a low cost, and situated so that transportation of 
the low-valued product is easy and cheap. These 
primary conditions are essential to the industrial 
usefulness of any pyrites bed. The production of 
pyrites on a commercial scale in the United States 
is at present confined to Massachusetts and Virginia. 

As a rapid and accurate method of estimating the 
sulphur available to the acid maker in a sample of 
pyrites, J. Cuthbert Welch has published the fol- 
lowing in the Analyst : Place 5 grammes of pyrites 
in a porcelain boat in a combustion tube, heat to 
redness, pass oxygen* over till combustion is com- 
plete, and absorb the gas formed in about 30 cubic 
centimeters of a solution of bromine in a mixture of 
equal parts of hydrochloric acid (specific gravity 
1.1) and water, in potash (or preferably nitrogen) 
bulbs. Wash out the solution into a beaker, boil, 
precipitate by boiling solution of barium chloride, 
cool, filter, and wash, dry and ignite the barium 

Talc or Soapstone, called Steatite when mas- 
sive, is a hydrated silicate of magnesia, from which 
the water is only driven off at a high temperature. 
It usually occurs in foliated laminar masses, like 
mica, but differs from the latter in not being elastic, 
in being softer and readily marked by the nail, in 
yielding an unctuous feeling powder and in not 
containing alumina as an essential ingredient. The 
laminated variety of talc has been adopted by min- 
eralogists as representing 1 in the scale of hardness ; 
its specific gravity is 2.7. The color is white, some- 

* The oxygen should be prepared from pure potassium chlorate 
in glass vessels, or at any rate in an iron one, kept especially for the 
purpose, and the gas should be passed through a strong solution of 
potash in the bulbs, through a U-tube containing calcium chloride, 
and lastly either through another calcium chloride tube or, prefer- 
ably, over phosphoric anhydride before use. 


times tinged with green, and the lustre pearly. 
When heated in a matrass, it undergoes no appre- 
ciable loss of water or transparency ; when subjected 
to a high heat it exfoliates and hardens, but does 
not melt. Acids have no effect upon it, either after 
or before ignition. Talc is quarried and employed 
for various purposes. It is mixed with clay to in- 
crease the translucency of the finished porcelain ; 
when powdered it is used for diminishing the fric- 
tion of machinery, and as a basis for colored cos- 
metic powders. Pencils are made from it for remov- 
ing grease from silks and cloths, and for marking 
out the paterns of clothes. 



Crude petroleum occurs only in the higher 
strata of rocks, it being never found in metamorphic 
rocks or crystalline formation. The Pennsylvania 
oil strata belong to the Devonian age, the anticlinal 
ridges being more favorable, it is said, than the 
synclinal ones. In Kentucky it occurs near the 
base of carboniferous limestone. In California it is 
found in strata belonging to the tertiary age, in 
Colorado and other western States, in those belong- 
ing to the cretaceous, and in North Carolina in 
those belonging to the triassic. In West Virginia 
it occurs in strata belonging to the coal measures. 
Crude petroleum is a fluid of a dark color, sometimes 
black, and contains 84 to 88 per cent, of carbon, the 
rest hydrogen. 

In prospecting for petroleum, the prospector, be- 
sides the customary outfit, should carry a stick pro- 
vided with a long iron point. It is best to follow 
the courses of rivers and creeks upward, because the 
progress of the work will not then be impeded by 
the turbidity of the water. It is also advisable to 
make such excursions in the warm season of the 
year, because the oil exudes more freely at that time 


than in cooler weather, when especially heavy oils 
and mineral tar, or maltha, are readily converted 
into a butyraceous mass. It is also best to wait 
until the water in the rivers and creeks is low. 

Observe whether the surface of the water exhibits 
variegated iridescent figures, this being especially 
the case in places where the water stands quietly or 
moves very little, for instance, in coves. Such an 
iridescent film, when found, may be due to petro- 
leum, but also to iron oxides and similar substances. 
However, by touching the surface of the water, for 
instance, with the iron-pointed stick, a film of oxide 
of iron may be disintegrated in angular pieces and 
very small flakes, which can be moved in any direc- 
tion, while oil films, when separated, reunite, and 
can be readily distinguished from allied indications 
by the many changes in color and figures. To be 
sure, films of very heavy oil may occasionally be 
met with which can be separated into angular pieces, 
behaving in this respect like iron oxides, but they 
almost invariably exhibit variegated movable rings 
of color. In swamps other substances may produce 
a phenomenon similar to crude oil. 

When indications of oil have in this manner been 
discovered in a quiet part of a water-course, try to 
remove the iridescent film of the water course and 
turn up the bottom by several times driving the 
iron-pointed stick into it. If films of oil together 
with bubbles of gas reappear, and this phenomenon 
occurs regularly after repeated experiments, there 
may be an outcrop of oil which deserves further 


However, if the work with, the iron-pointed stick 
yields negative results, the oil must have floated 
down from above, and the examination of the water 
course has to be continued until by means of the 
iron-pointed stick the source of the traces of crude 
oil has been found. This source will usually be in 
sandstone or other porous rock, and pieces knocked 
off with a hammer will exhibit the oil generally in 
the form of drops, partly upon the surfaces of the 
strata and partly also in small cavities. Instead of 
petroleum, mineral tar — a black, smeary mass — 
will frequently be found. 

The rock itself is occasionally impregnated, which 
may be recognized partly by the odor and partly by 
the so-called water-test For this purpose place a 
piece of the rock in quiet water, if possible exposed 
to the rays of the sun ; if the rock contains oil the 
characteristic iridescent colors appear, as a rule, 
immediately upon the surface of the water. 

The fresh fracture of oil-bearing sandstone is, as 
a rule, of a darker color than that of adjoining rock. 
After rain, drops of water adhere to out-crops of oil 
sandstone in a manner similar to that observed on 
other fatty substances. 

If in prospecting in water-courses oil-bearing 
sandstone has been found, the question has to be 
answered whether the prospector has to deal with 
contiguous rock or simply with an erratic block. 
This question can, as a rule, be decided without 
much difficulty, from the position of the stratifica- 
tion and the petrographic character of the rock in 


question as compared with the surroundings. How- 
ever, if there is still a doubt, examine, by means of 
the water-test, the portions of rock in the natural 
continuation of the block. 

Should the oil-bearing rock actually turn out to 
be an erratic block, the rock from which it has been 
derived will be found above, either on the slopes or 
in the water-course itself. Knowing the petro- 
graphic character of the oil-bearing block, it will 
not be difficult to find in the neighborhood the rock 
from which it is derived. In the above-described 
manner the water-courses are traced to the limits 
of the territory. In carrying on the work of pros- 
pecting, it is advisable to examine specimens of all 
the sandstone by means of the water-test, since the 
latter frequently shows the presence of petroleum, 
though there may be no external indications of it. 

It may be mentioned, that in cooler weather the 
traces of oil upon the surface of the water do not 
yield blue, red, yellow, etc., figures, or at least not 
very vivid ones, but a milky coloration, which 
possibly may also be due to other causes, so that 
determination is more difficult and less certain. 
This is another reason why it is advisable to select 
warm days for prospecting. That oil may also be 
detected by its odor need scarcely be mentioned. 

In swampy puddles iridescent films, which do not 
consist of iron oxides, but of hydrocarbons formed 
by decomposition, are occasionally met with. If due 
to the latter cause, they do not reappear, or at least 
only to a slight extent, when removed with the iron- 

256 prospector's field-book and guide. 

pointed stick from the surface of the water. How- 
ever, in examining the bottom, gas-bubbles gener- 
ally rise to the surface. Such puddles are examined 
first in the centre, and then by detaching pieces 
from the edges with the iron-pointed stick. 

Salses (mud-volcanoes), as well as abundant ex- 
halations of natural gas, if not derived from coal 
measures, are promising indications of the presence 
of petroleum in the territory. 

It need scarcely be mentioned that porous rock — 
if oil-bearing — justifies greater expectations than 
compact rock, and that larger quantities of oil may 
be looked for in oil-bearing sandstones of greater 

Although, generally speaking, a rich occurrence 
of oil may be inferred from abundant indications in 
the outcrop, the reverse is not always correct ; in 
many oil-fields, now productive, the indications 
when first found were not especially encouraging. 

If the oil occurs in definite geological horizons, 
the latter must be particularly searched for and 
traced and carefully examined in the water-courses 
crossing them, not only because the strata are there 
most denuded so as to allow of the best view of their 
geological structure, but also because the oil, since 
the restraining covering is wanting, has the best 
chance of exuding there, and the cut of the water- 
course is generally one of the lowest points of the 
outcrop, where the most abundant exudation takes 
place in consequence of the greater head of pressure. 

A very important question is whether the oil 


occurs in beds or in veins. In answering this ques- 
tion the following particulars may serve as guiding 
points : 

With proportionately greater denudation of the 
oil-bearing rock, it is sometimes possible directly to 
decide this question by observation, whereby the 
prospector, however, must take into consideration 
that even with a bed-like occurrence the oil will 
collect in small fissures. With a vein-like occur- 
rence a fissure may be traced to where it assumes 
larger dimensions in the strike and dip. 

If the prospector has to deal with a thick seam or 
stratum of sandstone, recognized as oil-bearing, im- 
bedded in another rock, for instance, shale, such 
seam should be traced and pieces freshly cut from it 
examined as to their content of oil by the water-test. 
If positive results are obtained, it may be inferred 
that the sandstone is the bearer of the oil, and that 
it is a bed-like occurrence. 

In a large mass of sandstone several outcrops of 
oil may sometimes be found at quite a distance 
from each other. If in tracing the stratum of the 
first outcrop according to its strike, the second, 
third, etc., outcrops are encountered, we have to do 
with a bed-like occurrence. This tracing of the 
stratum is effected by means of a compass, however, 
always with due consideration to the configuration 
of the ground. Suppose the cross-section of the 
sandstone bed with the declivity — the so-called out- 
crop-line — construed and traced. The outcrop-line 
will deviate the more from the straight line of 

258 prospector's field-book and guide. 

strike, the flatter the strata and declivities lie. In 
tracing the same stratum, it must be observed 
whether its strike does not change, which, of course, 
will necessitate a change in the route of the pros- 

If some promising outcrops of oil have been found, 
which will justify the execution of more extensive 
and more expensive prospecting work, it is advis- 
able to mark accurately in the sketch-map, in addi- 
tion to the outcrops, the relative heights, generally 
determined by an aneroid barometer, the strike and 
dip of the stratum reduced to the astronomical 
meridian, and the outcrops of well characterized 
concordant strata, for instance, imbedded shale, S, 
Fig. 61, no matter whether they lie in the upcast or 
downcast of the outcrops of oil, a. The relative 
heights of one of these strata are determined in 
several places, selecting points which can be readily 
found upon the map, and, if possible, lie at the same 
height, which can be readily effected without essen- 
tial error with the assistance of an aneroid barome- 
ter by taking observations in rapid succession. The 
points of same height, for instance, 1 and 2, give 
the strike of the stratum for a greater distance. 

By connecting the outcrops of oil a by a line AA, 
and again determining in the latter several points 
of the same height, for instance, 3, 4 and 5, the 
general strike is again obtained. If the latter runs 
parallel with the general strike of the characteristic 
stratum S, previously traced, one is justified in in- 
ferring a bed-like occurrence of oil, even if the con- 


strued dip of the outcrop line of oil corresponds 
with the observed local dip of the strata. 

In these investigations it is presupposed that the 
oil is recognized as exuding from the solid rock, an 
error regarding the outcrop of it being, therefore, 

Fig. 61. 

excluded. Such an error may, however, occur when 
the outcrop is covered with loose masses of earth 
and rock, to the base of which the oil exuding 
above flows down hidden, and escapes further below 
by some accidental cause. 

A vein-like occurrence of oil will not show the 



above-mentioned conformities with the characteristic 
concordant strata. Such an occurrence presupposes 
a fissure, which is generally connected with a throw 
of the strata. This is most frequently established 
by the fact that a characteristic stratum suddenly 
ends and does not reappear in its natural continua- 
tion, but either to the right or left, or higher or 
lower. If two or more such points of disturbance 

Fig. 62. 

have been found, their connecting line is the out- 
crop line of the fissure, Fig. 62. If this line passes 
through the outcrop a, or if several outcrops lie in 
it, a vein-like occurrence of oil must be inferred. 

However, sometimes the oil occurs in a maze of 
smaller and larger fissures. This is shown in the 
construction by the fact that in the presence of sev- 
eral outcrops a linear distribution of the same can- 
not be recognized, and that the combinations yield 


the most varying results, according to whether ex- 
ploration is carried on from the one or the other 
outcrop. Such occurrence presents uncommon dif- 
ficulties in prospecting. 

It need scarcely be mentioned that in prospecting 
for oil, it is of great importance to hunt up and map 
the anticlinals and their saddles, as well as faults. 

The directions here given for prospecting may 
have to be modified according to local conditions. 
With a sufficient preliminary knowledge of geology, 
any difficulties will, as a rule, be readily overcome 
by thoroughly digesting the principles of the direc- 
tions given. 

As regards the quality of the surface oil, it must 
be remembered that it is not a criterion for the oil 
occurring at greater depth. The oil thickens on 
the surface of the earth, and with increasing density 
becomes viscous and dark. If pale, limpid, and 
specifically lighter oil is found at the outcrop, it is 
sure evidence of oil of excellent quality at greater 
depth. In every case it may be expected that the 
quality of the oil at greater depth is superior to that 
at the outcrop. 

Ozocerite is a mineral paraffine or wax, and 
occurs generally in fissures and cavities in the 
neighborhood of coal-fields and deposits of rock salt, 
or under sandstone pervaded with bitumen. It is 
found in various localities in Africa, America, Asia 
and Europe. In the United States it occurs in 
Arizona, Texas and Utah. 

The most interesting deposit is in East Galicia, 



The ozocerite occurs there in a saliferous clay be- 
longing to the miocene of the more recent tertiary 
period, and forming a narrow, almost continuous 
strip on the northern edge of the Carpathian Moun- 
tains. This miocene group of saliferous clay con- 
sists chiefly of bluish and variegated clays, sands 
and sandstones, with numerous occurrences of gyp- 
sum, rock salt and salt springs. In Boryslaw, the 
strata of saliferous clay form a perceptible saddle as 

Fig. 63. 

of Ozo&erc'te 

they sink on the south below the so-called menilite 
slates, which are very bituminous and foliated, and 
form here the most northern edge of the Carpathian 
Mountains. The principal deposit of ozocerite con- 
verges with the axis of this saddle as shown in Fig. 
63, 8 being the strata of saliferous clay, and M 
menilite slate. 

Closely allied to ozocerite are the following min- 
eral resins : 


Retinite, generally of a yellowish-brown, some- 
times of a green-yellow or red color. It is found 
with brown coal in various localities. 

Elaterite or elastic bitumen, of a blackish 
brown color, subtranslucent, and occurring in soft, 
flexible masses in the lead-veins of Castleton, in 
Derbyshire, in the bituminous sandstone of Wood- 
bury, Connecticut, etc. 

Pyropissite occurs in strata in brown coal. 

Ozocerite occurs in various shades of color, from 
pale yellow to black ; when melted it generally 
shows a dark-green color. The pale varieties are 
chiefly found in places containing much marsh gas. 
The dark-green, heavy variety is the best, while the 
black kind, or asphaltic wax, is the poorest ; it con- 
tains resinous combinations of oxygen, and is inter- 
mediate between mineral oil and ozocerite. 

The odor of ozocerite is, according to its purity, 
agreeably wax-like. In consistency it is soft, pli- 
able, flexible to hard ; the mass in the latter case 
showing a conchoidal fracture, but softens on 
kneading. The boiling point lies between 133° 
and 165° F., and of the so-called " marble wax" 
even as high as 230° F. The specific gravity is 
from 0.845 to 0.930. 

Ozocerite is readily soluble in oil of turpentine, 
petroleum, benzine, etc., and with difficulty in 
alcohol and ether ; it burns with a bright flame, 
generally leaving no residue. Its elementary com- 
position is about that of petroleum, 85 per cent, of 
carbon and 15 per cent, of hydrogen. 

264 prospector's field-book and guide. 

Native Asphalt or Bitumen is solid at the ordi- 
nary temperature, of a black to blackish-brown 
color and a conchoidal fracture with glossy lustre. 
Hardness 1 to 2 ; specific gravity 1 to 2. It melts 
at 90° F., and is very inflammable. It appears to 
be formed by the oxidation of the non-saturated 
hydrocarbides in petroleum. The most remarkable 
deposits are in Cuba, Trinidad, and Venezuela. 
Other noted localities are the Dead Sea, Seyssel 
(France), Limmer, the Abruzzo, and Val de Travers. 
It occurs also of every degree of consistence, and in 
immense quantity, along the coast of the Gulf of 
Mexico, chiefly in the States of Tamaulipas, Vera 
Cruz and Tabasco, where not unfrequently it is as- 
sociated with rock salt and "saltpetre." It also 
occurs in Utah in widely separated places. It has 
been found associated with ozocerite and more ex- 
tensively as melted out of sandstone. California 
includes a large area which furnishes asphalt, much 
the larger proportion being the product of the de- 
composition of petroleum, while the remainder 
occurs in veins that are evidently eruptive, the for- 
mer occurring in beds of greater or less extent on 
hill-sides or gulch slopes, below springs of more 
fluid bitumen. These deposits are scattered over 
the country between the bay of Monterey and San 
Diego, but are chiefly observed west and south of 
the coast ranges, between Santa Barbara and the 
Soledad pass. Asphalt occurs also in other localities 
in the United States, for instance in Connecticut, in 
thin seams and veins in eruptive rock ; in New 


York in the region of eruptive and metamorphic 
rocks, in Tennessee in the Trenton limestone, etc. 
In some American specimens sulphur has been 
found to the extent of 10.85 per cent. Asphalt is 
in great request for paving purposes ; it is of in- 
creasing value, and deposits are eagerly sought for. 

Peat. Peat is not a mineral, but consists of the 
cumulatively resolved fibrous parts of certain mosses 
and graminacese. It gradually darkens from brown 
to black with increasing age. It occurs in beds or 
in bogs. As a fuel it is most economically used at 
the place where it is grown. Good peat yields about 
3 to 6 per cent, of tar proper, which is comparatively 
easy to purify by the usual method. 

The examination of a peat bog is very instructive 
with reference to the formation of coal as affording 
examples of vegetable matter in every stage of de- 
composition, from that in which the organized 
structure is still clearly visible to the black carbon- 
aceous mass which only requires consolidation by 
pressure in order to resemble a true coal. 



Although many varieties of gems and precious 
stones are known to occur in the United States, 
systematic mining for them is carried on only at a 
few places, and the annual output is still very small 
in comparison with the prospective extent of the 
field. Not many persons are familiar with the ap- 
pearance of gem stones in their native state, so that 
while quartz pebbles are often mistaken for rough 
diamonds, garnets for rubies, ilmenite for black 
diamonds, etc., on the other hand it is quite proba- 
ble that many valuable occurrences have escaped 

Many of the gems are of comparatively little 
value, so that it is not always profitable to pay 
much attention to their discovery unless the quan- 
tity of them is great, for the cost of polishing is an 
important factor in assigning a value to them. 
Many colored transparent and translucent kinds of 
quartz colored by metallic oxides fall under this 
category. But it is so easy to prospect a stream, for 
instance, in a country of crystalline, plutonic, or 
metamorphic rocks, that a search for precious stones 
and gems of all kinds should be made much more 
frequently than is usually the case. With regard to 


the precious varieties, it is well to bear in mind that 
the valuable specimens may be associated with all 
sorts of worthless specimens, all of which, though 
impure in quality, may really be sapphires, spinels, 
chrysoberyls, tourmalines, zircons, etc. 

Though many are translucent rather than trans- 
parent, many dark in outward appearance, and all 
water-worn, more or less, and with surfaces not at 
all glass-like, and the majority not apparently trans- 
parent or translucent unless held up to the light, yet 
here and there a good specimen may be found. 
For all that, a knowledge of the general appearance 
of such impure specimens is probably of as much 
importance as that of the good ones, for the pros- 
pector who comes across them has an encouragement 
in his search for valuable ones. 

For some reason or other, diamonds and gold are 
often found in the same alluvial deposit, and aurif- 
erous beds should therefore be examined for the 
precious stone. The specific gravity of the diamond 
— higher than that of quartz or most pebbles — and 
that of gold are so very different that it does not 
follow that, for instance in a stream bed, these two 
minerals are always found close together. 

Whilst certain characteristics of precious stones, 
such as hardness and specific gravity, given in the 
table later on, may be useful to the prospector, yet 
it is not always an easy matter to distinguish a cer- 
tain precious stone from one which may be similar 
in appearance though perhaps of much less value. 
To assist any one in doubt, and in many instances 

268 prospector's field-book and guide. 

to settle the point, the diehroiscope, Figs. 64 and 65, 
is very useful, taking for granted that some practice 
with the various kinds of translucent or transparent 

Fig. 64. 


stones of various shades and colors has been ac- 
quired. The diehroiscope is in the shape of a cylin- 

Fig. 65. 

When a transparent or semi-transparent stone is examined through the 
diehroiscope, the color of the square A is different or of a different shade to 
that of the square B when dichroism exists. 

der 2 inches long and 1 inch in diameter, and thus 
easily carried about.. 

Placing by means of tweezers a translucent or 
transparent stone close to the one end of the instru- 


ment where the two square images are seen when 
the instrument, held skywards, is looked into, and 
turning it about in various directions, and at the 
same time turning the instrument round, the ob- 
server will notice whether the color of the two 
squares is one and the same. If the stone is amor- 
phous, such as flint, obsidian, etc., or crystallizing 
according to the cubic system, such as diamond, 
spinel ruby, garnet, etc., the two squares will be of 
the same color to that of the other when the colored 
stone is examined in certain directions, though it 
may be the same in certain others. 

Thus a true ruby, which affords two shades of 
pink, can be distinguished from a spinel ruby or 
garnet without dechroism, or from a pink tourma- 
line, which gives two colors but somewhat differ- 
ently to those of ruby ; so, too, a sapphire, which 
gives a blue shade in one square, and a light shade 
of color without any shade of blue in the other, can 
be distinguished from an amethyst, which affords 
two shades of purple, or from a blue spinel, which 
does not show any twin coloration, or from an iolite 
(or water sapphire), in which the coloration is of its 
own kind. 

A tourmaline, either the green or brown variety, 
can be recognized directly by the color of the one 
square being quite dark compared to that of the 

An emerald affords two distinct shades of green 
(one bluish), easily remembered, so a green garnet, 
which does not show twin colorations, cannot be 
mistaken for it, 

270 prospector's field-book and guide. 

With the dichroiscope and two or three minerals, 
such as the sapphire, topaz and rock crystal to test 
for hardness and a little practice, and a slight 
knowledge of the crystallization of minerals which, 
though frequently found water-worn, not uncom- 
monly retain traces of the original crystal edges and 
faces, the prospector can examine his specimens 
with a very much easier mind than he would with- 
out them. Frequently neither the hardness of a 
gem stone nor its behavior before the dichroiscope 
is sufficient to enable its identity to be reliably 
known. In such a case its specific gravity may 
settle the question, but this may require a more ac- 
curate balance than the prospector may possess, and 
the advice of an expert may be necessary. 

Diamond. Diamonds are usually met with in 
alluvial soil, often on gold-diggings. In some In- 
dian fields a diamond-bearing conglomerate occurs 
which is made up of rounded stones cemented 
together, and lies under two layers, the top one 
consisting of gravel, sand and loam, the bottom 
one of thick clay and mud. In the neighborhood 
of Pannah, between Sonar and the Sona river 
diamonds are found in ferriferous pebble conglom- 
erate and in river alluvium. The most beautiful 
crystallized specimens are, however, found on the 
west side of the Nalla-Malla mountains, near Ban- 
ganpally, between Pennar and Kistnah, in a dia- 
mond-bearing layer between beds of primitive con- 

In Borneo, the diamond is found associated with 


magnetic iron ore, gold and platinum, in alluvial 
deposits consisting of serpentine and quartz frag- 
ments as well as marl. 

In Brazil, the province Minas Geraes is rich in 
diamonds, the most important occurrence being at 
Sao Joao do Barro, where they are found in an en- 
tirely weathered talcose slate. In other parts of the 
same country the diamond is also obtained from a 
conglomerate of white quartz, pebbles and light 
colored sand, sometimes with yellow and blue 
quartz and iron sand. In the province of Bahia 
occurs a substance known as carbonado or black dia- 
mond. It is an allotropic form of carbon closely 
related to the diamond, and is found in small irreg- 
ular crypto-crystalline masses of a dark gray or 
black color. Although its density is not so great as 
that of the diamond, it is very much harder ; in fact, 
it is the hardest substance known. At first it was 
used only in cutting diamonds, but since the inven- 
tion of the core-drill for boring in rocks it has found 
a greatly extended use, and is now employed for the 
so-called " diamond crown " of this drill. The bort 
of the South African mines finds a similar industrial 
application, being worthless as a gem. 

In South Africa the diamond occurs associated 
chiefly with garnet and titanic iron ore, as well as 
with quartz opal, calcareous spar, and more rarely 
with iron pyrites, bronzite, smaragdite and vaalite. 
According to St. Meunier the South African dia- 
mond-bearing sands are composed of an exceedingly 
large number of constituents, eighty different vari- 


eties of minerals and rocks having been found in 
them. Of minerals occur, for instance, diamond, 
topaz, garnet, bronzite, ilmenite, quartz, tremolite, 
asbestus, wallastonite, vaalite, zeolite, iron pyrites, 
brown iron ore, calcareous spar, opal, hyalite, jasper, 
agate, clay. Of rocks are found, serpentine, eklo- 
gite, pegmatite and talcose slate. At the Kimberley 
mine, which more or less represents others in the 
neighborhood, the diamond-bearing ground forms a 
"pipe" or " chimney " surrounded by formations 
totally different from the payable rock. The en- 
casing material is made up of red sandy soil on the 
surface, underneath which is a layer of calcareous 
tufa, then yellow shale, then black shale, and below 
this, hard igneous rock. The diamond-bearing 
ground consists of " yellow ground " (really the de- 
composed " blue ground "), which is comparatively 
friable ; and deeper down the " blue ground " 
(hydrous magnesian conglomerate), which needs 
blasting by dynamite. The " blue ground " is of a 
dark bluish to a greenish gray color and has a 
more or less greasy feel. With it are mixed por- 
tions of boulders of various kinds of rocks such as 
serpentine, quartzite, mica-chist, chlorite-chist, 
gneiss, granite, etc. All this "blue ground" has 
evidently been subjected to heat. The gems are in 
the matter which binds these rocks, not in the rocks 

Diamonds are also found in the Ural, various 
parts of Australia, New Zealand and in the United 
States. In the latter country diamonds have been 


found at a number of localities, but never enough to 
warrant any extended mining for them. Many ex- 
perienced geologists hold to the opinion that since so 
many associations of the diamond are present in 
North Carolina they have hopes of their being found 
there. The garnet districts of Arizona and New 
Mexico may also be looked upon as favorable for 
the occurrence of this gem. Of the localities where 
diamonds have been found in the United States may 
be mentioned : The gold diggings of Twitty's mine 
in the itacolumite region of Rutherford Co., North 
Carolina, 1847 ; further in Hall Co., Georgia, 1850, 
in the gold diggings of the south slopes of the 
Alleghany mountains, in Arizona, and in Califor- 
nia, together with platinum in various gold dig- 
gings. Further at Dysartville, McDowell Co., North 
Carolina, in Idaho, San Juan Co., Colorado, and 
Cherokee Flat and several other localities in Butte 
Co., California. 

The natural surface of the diamond is often 
unequal ; its sides are lined, somewhat convex, and 
generally appear dulled, or as they are commonly 
called, rough, by the evident action of fire. The 
diamond breaks regularly into four principal cleav- 
ages. It does not sparkle in the rough, and the 
best test is its hardness and its becoming electric, 
when rubbed before polishing. The color of the 
diamond varies through all tones of the color-scale, 
from absolute colorless through all shades of yellow, 
red, green, blue to intense black. Some colorless 

274 prospector's field-book and guide. 

diamonds acquire on heating a reddish shade, which 
disappears on cooling. 

The occurrence of diamonds of different colors 
affords a remarkable illustration of what has been 
said about the colors of minerals. As pure carbon, 
diamond is colorless, as are also the microscopic 
diamonds artificially produced by an electric cur- 
rent, but in nature the stones are of different colors, 
which are imparted to them by a very small pro- 
portion of foreign matter. The yellow and gray 
tints decrease the value of the diamond, but red, 
blue and green varieties, on the contrary, are so 
rare, that when diamonds are so colored their value 
is considerably greater than if perfectly colorless. 
For instance, the best blue diamond known is esti- 
mated at double the calculated value of a good 
colorless diamond of the same size. 

In Borneo a kind of black diamond is found 
which is very highly prized in consequence of its 
exceptional lustre and rarity. It is even harder 
than the ordinary diamond. 

The specific gravity of the pure diamond varies 
from 3.5 to 3.6 ; that of the black diamond is from 
3.012 to 3.255. 

One of the most beautiful qualities of the diamond 
is its power of refraction ; that of water is 0.785 ; 
that of the ruby, 0.739 ; that of the rock crystal, 
0.654 ; that of the diamond, 1.396. The refraction 
of the diamond is single in the entire crystals ; when 
broken it possesses double, but imperfect refraction, 
in the thin layers. 



The value of the diamond is dependent on its 
color, its size and the finish given to it by working. 
Perfectly colorless stones bring the highest price, 

Fig. m. 

and next stones with a reddish, greenish andjbluish 
shade, which, however, are quite rare. Yellowish 
diamonds are of less value, the price paid for them 
being the lower the more the yellow color plays into 

276 prospector's field-book and guide. 

Of the largest diamonds each has its own name 
and its own history. Of these may here be men- 
tioned the Koh-i-noor or mountain of light, Fig. 66, 
d. It weighs 106 T V carats. The Orlof, Fig. 66, a, 
weighs 194| carats, and is as large as half a pigeon's 
egg ; it adorns the sceptre of the Russian emperor. 
The Grand Duke of Tuscany or Florentine, Fig. 66, 
b, is one of the most beautiful diamonds. It is a 
yellow diamond, and weighs 139| carats. It be- 
longs to the house of Austria. The Pitt or Regent, 
Fig. 66, c, belongs to the French treasury and, 
with the exception of the Koh-i-noor, is the most 
beautiful and most regular diamond. It weighs 
136| carats. 

Sapphire. The sapphire is the blue variety of 
corundum in its purest crystalline state. Its gen- 
eral composition is alumina 92, silica 5.25, oxide of 
iron 1.0. The color most highly valued is a highly 
transparent bright Prussian blue. More frequently 
the color is a pale blue, passing by paler shades 
into perfectly colorless varieties. The paler varieties 
are frequently marked by dark blue spots and 
streaks which detract from their value. But these 
paler varieties lose their color when subjected to 
great heat, a fact that has sometimes been taken 
advantage of b}^ unscrupulous dealers to pass them 
off as diamonds. 

The principal form of the sapphire is an acute 
rhomboid, but it has many modifications and va- 
rieties. On being broken it shows a conchoidal 
fracture, seldom a lamellar appearance. The prin- 


cipal locality for sapphires in the United States is 
in the garnet districts near Helena, Montana ; Santa 
Fe, New Mexico ; southern Colorado and Arizona. 
Here they occur in the sand, associated with peri- 
dot, pyrope and alinandine garnet. 

Ruby. The ruby is the red variety of corundum 
and in composition varies from almost pure 
alumina to a compound containing 10 to 20 per 
cent, of magnesia, and always about 1 per cent, of 
oxide of iron. The ruby is subdivided into several 
varieties according to color, which in its turn is 
affected by mineral composition, spinel ruby occur- 
ring in bright red or scarlet crystals, rubicelle of an 
orange red color, bala ruby rose red, almandine ruby 
violet, chlorospinel green, and pleonast is the name 
given to dark varieties. 

The crystals are usually small and when not 
defaced by friction they have a brilliant lustre, as 
has also the lamellar structure, with natural joints 
which it shows on being broken. It exhibits va- 
rious degrees of transparency. The color most 
valued is the intense blood red or carmine color of 
the spinel ruby. When the color is a lilac blue, 
the specimen was formerly known as the Oriental 
amethyst, and was regarded as a connecting link be- 
tween the ruby and the sapphire. In the United 
States the ruby is found in various localities, in 
some of which the cr} 7 stals have partly decomposed 
and show a soft structure resembling steatite. It 
occurs in gneissic and metamorphic rocks and in 
granular limestone. In Ceylon it is found with the 
sapphire in the river deposits. 

278 prospector's field-book and guide. 

Topaz is composed of silica, alumina and fluorine. 
It occurs in prismatic crystals, sometimes furrowed 
lengthwise, variously terminated, breaking easily 
across with smooth brilliant cleavage. Transparent 
or semi-transparent. White, yellow, greenish, blu- 
ish, pink. Lustre, glassy. Specific gravity, 3.5. 
Hardness, 8. Scratches quartz ; is scratched by 
sapphire. Infusible, but often blistered and altered 
by heat. When smooth surfaces are rubbed on 
cloth they become strongly electric, and can attract 
small pieces of paper, but rough surfaces do not 
show this. The brilliant cleavage of topaz distin- 
guishes it from tourmaline and other minerals. 
Topaz occurs in gneiss or granite with tourmaline, 
mica, beryl ; also cassiterite or tin-stone, apatite, 
fluorite. The white topaz resembles the diamond, 
but unlike the latter it can be scratched by sapphire. 
The pale blue variety is of value for cutting into 
large stones for brooches ; specimens are occasion- 
ally found of several pounds weight. Topaz of a 
beautiful sherry color occurs in Brazil. Specimens 
of this when heated become pink, when they are 
known as burnt topaz. The yellow varieties are 
cut as gems. Although not very valuable, they are 
quite brilliant and look very well. 

Topaz has been found in Arizona, New Mexico, 
and occasionally in southern California. In the 
latter state, and in Utah and Mexico, it sometimes 
occurs in fine, clear crystals in volcanic rocks. A 
notable locality, especially for very large crystals, 
is at Stoneham, Maine, and another at Trumbull, 


Beryl or Emerald is composed of silica, alumina, 
and beryllium or glucinum. It is almost always 
found in distinct crystals, and usually in forms easy 
to recognize. The crystals are hexagonal prisms, 
usually green, transparent or opaque. Lustre, 
glassy ; fracture uneven ; specific gravity, 2.7 ; hard- 
ness, 7 to 8 ; scratches quartz. Infusible, or nearly 
so, but becomes clouded by heating. Occurs in 
granite rocks with feldspar and quartz. Valuable 
for jewelry when transparent and rich grass-green 
(emerald) or sea-green (aquamarine). Emerald has 
been found in North Carolina and aquamarine at a 
number of localities in the United States. 

A productive emerald mine is that of Muso, in 
New Granada, Mexico. The emerald occurs in 
veins and cavities in a black limestone that contains 
fossil ammonites. The limestone also contains 
within itself minute emeralds and an appreciable 
quantity of glucina. When first obtained the em- 
eralds from this mine are soft and fragile ; the 
largest and finest emeralds could be reduced to 
powder by squeezing and rubbing them with the 
hand. After exposure to the air for a little time 
they become hard and fit for the jeweler's use. 

Phenactte is a silicate of beryllium or glucinum. 
Its hardness is about the same as topaz and its 
specific gravity 3.4 to 3.6. It occurs in glassy 
rhombohedral crystals, and its hardness, beautiful 
transparency and color make it valuable for cutting 
as a gem, since it is capable of extreme polish. 
Phenacite has been found at Pike's Peak, Colorado, 

280 prospector's field-book and guide. 

in crystals of sufficient size and quality to furnish 
fair gems. 

Zircon is composed of silica and zirconia. It is 
found in square prisms terminated by pyramids, 
and in octahedrons, but often also in pebbles and 
grains. Transparent or opaque. Wine or brown- 
ish red, gray, yellow, white. Lustre, glassy ; frac- 
ture, usually irregular, but in one direction it can 
be split so as to exhibit a smooth even cleavage 
face having an adamantine lustre like the diamond. 
Specific gravity 4.0 to 5.0 ; hardness 7.5 ; scratches 
quartz, is scratched by topaz. Infusible ; the red 
varieties, when heated before the blowpipe, emit a 
phosphorescent light, and become permanently col- 
orless. Zircon occurs in syenite, granite, basalt. 
In some regions it occurs in the rock so abundantly 
that when the rock has been worn down by the 
weather, it is left unaltered in considerable quanti- 
ties. It may then be obtained by washing the 
gravel in the manner of the gold miner. Clear 
crystals are used in jewelry, in jeweling watches, 
and imitation of diamond. It may be distinguished 
from the latter by its inferior hardness, and in not 
becoming so readily electric by friction. Fine 
crystals are obtained in New York and Canada ; 
and good specimens also come from North Carolina 
and Colorado. 

Garnet is composed of silica, alumina, lime, 
iron, magnesia, manganese. It is found almost 
always in distinct crystals, and as these crystals are 
commonly isolated and scattered through the rock, 


it is not difficult to recognize them. The crystals 
are usually twelve-sided, having the form of a 
rhombic dodecahedron. They are transparent or 
opaque ; generally red ; also brown, green, yellow, 
black, white. Lustre, glassy or resinous ; fracture 
conchoidal or uneven ; specific gravity 3.5 to 4.3 ; 
hardness, 6.5 to 7.5 ; cannot be scratched with a 
knife. Fusible with more or less difficulty. Red 
varieties impart a green color to borax bead owing 
to presence of chromium. Garnet usually occurs in 
crystals scattered through granite, gneiss or mica 
schist, also in crystalline limestone ; with serpen- 
tine or chromite; also in some volcanic rocks. Fine 
colored transparent varieties (carbuncle, cinnamon 
stone, almandine) are used in jewelry. The garnets 
found in New Mexico and Southern Colorado, and 
there called " rubies," are as line as those from any 
other locality, the blood-red being the most desir- 
able. Very fine crystals of cinnamon stone, cinna- 
mon garnet or essonite have been found in New 
Hampshire, Maine, and at many other points in 
the United States. 

Tourmaline is composed of silica, alumina, mag- 
nesia, boracic acid, fluorine, oxides of iron (lime 
and alkalies). It is found in prisms with three, six, 
nine or more sides, furrowed lengthwise, terminat- 
ing in low pyramids. Commonly black and opaque, 
rarely transparent, and of a rich red, yellow, or 
green color. Lustre glassy ; fracture uneven ; spe- 
cific gravity 3.1 ; hardness 7 to 8 ; cannot be 
scratched with a knife. When the smooth side of 

282 prospector's field-book and guide. 

a prism is rubbed on cloth it becomes electric and 
can attract a small piece of paper. Tourmaline 
occurs in granite and slate. Only the fine colored 
transparent varieties, which are used as gems and 
for optical purposes, are of value. The principal 
source of tourmaline in the United States is the 
locality Mount Mica, at Paris, Maine. 

Epidote is a silicate of alumina, iron and lime, 
but varies rather widely in composition, especially 
as regards the relative amounts of alumina and 
iron. It is usually found in prismatic crystals, 
often very slender and terminated at one end only ; 
they belong to the monoclinic system. Lustre, 
vitreous ; color, commonly green, although there 
are black and pink varieties. Epidote is found in 
many localities in the United States and in very 
large crystals ranging from brown to green in color, 
but as a rule the crystals are only translucent or 
semi-opaque, though some stones of considerable 
value and great beauty have been found in Rabun 
county, Georgia. 

Opal is composed of silica and water. It is never 
found in crystals, but only in massive and amorphous 
form. Fracture, conchoidal ; specific gravity 2.2 ; 
hardness, 6 ; can be scratched by quartz and thus 
distinguished from it. It is infusible and generally 
milk-white. The most beautiful variety of opal is 
that called precious opal, which exhibits a beautiful 
play of colors and is a valuable gem. One kind of 
precious opal with a bright red flash of light is 
called the fire opal, and another kind is the harle- 


quin opal. Common opal does not exhibit this play 
of colors, and it varies widely in color and appear- 
ance. Milk opal, as one variety is called, has a pure 
white color and milky opalescence, while resin opal 
or wax opal has a waxy lustre .and yellow color. 
Jasper opal is intermediate between jasper and opal ; 
wood opal is petrified wood, in which the mineral 
material is. opal instead of quartz. Opal is com- 
monly met with in seams of certain volcanic rocks ; 
sometimes it occurs in limestone and also in metal- 
lic veins. Precious opal is rare in the United 
States, though some of high value is said to have 
been found in Creek Co., near John Davy's River, 

Turquois is a hydrated phosphate of aluminium, 
containing also a little copper phosphate, which is 
probably the source of the color, which in the most 
precious variety is robin's-egg blue, and bluish- 
green in less highly prized varieties. It occurs only 
in compact massive forms, filling seams and cavi- 
ties in volcanic rock. Specific gravity 3.127. Tur- 
quois has been found in the Holy Cross mining 
region, thirty miles from Leadville, Colorado, and 
of late years a number of mines have been opened 
in New Mexico, at Los Carillos and in Grant 
County. The latter mines produce stones having a 
faint greenish tinge, which is either due to a partial 
change or metamorphism, which has taken place 
while the turquois was in the rock, or it may be a 
local peculiarity. Turquois occurs also in Arizona 
and at a point in Southern Nevada. At the latter 

284 prospector's field-book and guide. 

place it is found in veins of small grains in a hard 
shaly sandstone. The color of this turquois is a 
rich blue, almost equal to the finest Persian, and 
the grains are so small that the sandstone is cut 
with the turquois in it, making a rich mottled stone 
for jewelry. 

Agate is found in almost every part of the world, 
and the difference of the constituent parts makes 
the specific gravity vary from 2.58 to 2.69. The 
agate, properly so called, is naturally translucent, 
less transparent than crystalline quartz, but yet 
less opaque than jasper. It is too hard to be even 
scratched by rock crystal. It takes a very good 
polish. It is never found in regular forms, but 
always either in nodules, in stalactites, or in irregu- 
lar masses. Eye agates consist of those parts of the 
stone in which the cutting discovers circular bands 
of very small diameter arranged with regularity 
round one circular spot. These circles are fre- 
quently so perfect that they appear to be traced by 
the compass. The first round is white, the second, 
black, green, red, blue or yellow ; the most rare are 
those whose circles are at equal distance from the 
centre. Moss agate contains brown-black, moss-like 
or dendritic forms distributed rather thickly through 
the mass. These forms consist of some metallic 
oxide (as of manganese). Of all the American 
stones used in jewelry there is no other of which so 
much is sold as the moss agate. The principal 
sources of supply are Utah, Colorado, Montana and 


Chalcedony is a semi-transparent variety of 
quartz, of a waxy lustre and varying in color from 
white through grey, green and yellow to brown. 
It is translucent or semi-transparent. It occurs in 
stalactite, reniform or botryoidal masses, which 
have been formed in cavities in greenstones and 
others of the older rocks. Into these cavities, as 
into miniature caverns, water holding silicious 
matter has penetrated and deposited its solid con- 
tents, consisting almost exclusively of silica tinged 
by the presence of other minerals. Some of these 
cavities are several feet in diameter, and besides the 
coloring of the encircling mass there are often, in 
the interior of the concretions in them, cavities or 
central nuclei which contain sometimes as many as 
twenty-four different substances, as silver, iron 
pyrites, rutite, magnetite, tremolite, mica, tourma- 
line, topaz, with water, naphtha, and atmospheric 

Chrysoprase is of a beautiful apple-green color, 
due to oxide of nickel. In a warm, dry place the 
color of chrysoprase is destroyed, but it can be again 
restored by keeping it damp. 

Carnelian and Sard have red or brownish tints 
and are varieties of chalcedony. 

Jasper is quartz rendered opaque by clay, iron 
and other impurities. It is of a red, yellow or green 
color. Sometimes the colors are arranged in rib- 
ands, or in other fantastic forms. It is used for 
ornamental work. 

Bloodstone or Heliotrope is green jasper, with 
splashes of red resembling blood spots. 

286 prospector's field-book and guide. 

Rock crystal is pure, transparent, colorless 
quartz, and is found at a great many localities in 
the United States, In Herkimer County, at Lake 
George, and throughout the adjacent regions in 
New York state, the calciferous sandstone contains 
single crystals, and at times cavities are found filled 
with doubly terminated crystals, often of remarkable 
perfection and brilliancy. These are collected, cut, 
and, often uncut, are mounted in jewelry and sold 
under the name of " Lake George diamonds." 

Amethyst is a transparent variety of quartz of a 
rich violet or purple color due to the oxide of man- 
ganese which it contains. It crystallizes in the form 
of a hexagon, terminated at the two heads by a 
species of cone with six facets. These crystals are 
often in masses, and the base is always less colored 
than the top. Amethysts are generally found in 
metalliferous mountains, and are always in combi- 
nation with quartz and agate. They occur in many 
localities in the United States, but not in as fine or 
large specimens as in Brazil or Siberia. 

Rose Quartz is pink, red and inclining to violet- 
blue in color. Occurs in fractured masses and is 
imperfectly transparent. The color is most perma- 
nent in moisture. 

Smoky Quartz are quartz crystals tinted with a 
smoky color, becoming sometimes black and opaque. 

Yellow or Citron Quartz or False Topaz 
occurs in light-yellow translucent crystals. It is 
often set and sold for topaz, but it may be distin- 
guished from it by the absence of cleavage. 


Onyx and Sardonyx. A variety of quartz hav- 
ing a regular alternation of strata more or less even, 
and variously colored in black, white, brown, gray, 
yellow and red. When the onyx has one or two 
strata of red carnelian, it is more valued and takes 
the name of sardonyx. In the onyx the dark strata 
are always opaque and contrast strongly with the 
clear, which, when thinned, become almost trans- 

Cat's Eye consists of a quartz mixed with paral- 
lel fibres of asbestus and amianthus. It is found in 
pebbles and in pieces more or less rounded : it has a 
concave fracture ; is translucent and also transpar- 
ent at the edges. It has a vitreous and resinous 
light. It is generally either green, red, yellow or 
gray. It marks glass. Its specific gravity is from 
2.56 to 2.73. When exposed to a great heat it loses 
lustre and transparency, but does not melt under 
the blowpipe unless reduced to minute fragments. 

Many other gem stones are known to occur in the 
United States, and the following list compiled by 
Mr. George F. Kunz * is here given : 

* Mineral Kesources of the United States, Washington, 1883. 



List of gem stones known 
Achroite (tourmaline). 
Agate (quartz). 
Agatized wood (quartz). 
Almandine (garnet). 
Amazon stone (microlene). 

Amethyst (quartz). 
Aquamarine (beryl). 
Bowenite (serpentine). 
Cairngorm (quartz). 

Chalcedony (quartz). 

Diopside (pyrozene). 
Elpeolite (nephelite). 
Emerald (beryl). 

Essonite (garnet). 
Fleche d'amour (quartz). 
Fossil coral. 

Grossularite (garnet). 

Hiddenite (spodumene). 
Hornblende in quartz. 

Indicolite (tourmaline). 

to occur in the United States. 

Jet (mineral coal). 

Labrador spar (labradorite). 
Lake George diamonds (quartz). 
Lithia emeralds (spodumene). 

Moonstone (feldspar group). 
Moss agate (quartz). 
Novaculite (quartz). 

Olivine (chrysolite). 
Opalized wood (oyal). 
Peridot (chrysolite). 
Pyrope (garnet). 

Rock crystal (quartz). 
Rose quartz (quartz). 
Ruby (corundum). 
Rubellite (tourmaline). 

Rutile in quartz (quartz). 
Sagenite (quartz). 
Sapphire (corundum). 
Silicified wood (quartz). 
Smoky quartz (quartz). 
Smoky topaz (quartz). 
Sunstone (feldspar). 
Thetis hair stone (quartz). 




Venus hair stone quartz. 


Williamsite (serpentine). 

Wood agate (quartz). 

Wood jasper (quartz). 

Wood opal (opal). 


Zonochlorite (prehnite). 

List of species and varieties found in the United States, but not met 
with in gem form. 








Prase (quartz). 



List of species and varieties not yet identified in any form in the 
United States. 


Cat's-eye chrysoberyl 
Cat's-eye quartz. 
Chrysoberyl cat's eye 

Quartz cat's eye. 

List of gem stones occurring only in the United States. 





Lithia emerald. 




Thetis hair stone. 





290 prospector's field-book and guide. 





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Fluorine, 15.06 
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Alumina, 15.75 
Glucina, 12.50 
Oxide of iron, 1.00 
Lime, • 0.25 

Silica, 33.0 
Zircoma, • 66.8 
Peroxide of iron, 0.10 

Silica, 38.25 
Alumina, 19.35 
Red oxide of iron, 7.33 
Lime, 31.75 
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Mr. Leon Draft and Mr. Alfred Williams have 
invented a method of finding ore by means of elec- 
tricity, by which they claim to be able to detect the 
presence of certain mineral ores invisible to the eye 
and undiscoverable by mining engineering. It is 
claimed that by this method not only can deposits 
be located, but that the extent and depth of the 
lode can be determined with an accuracy that is 
quite impossible with any existing system of pros- 

In working this method there are two stations, 
the transmitting and receiving. At the former 
there is a battery of 12 volts, giving 4 amperes and 
50 watts ; a special form of break works in methyl- 
ated spirits, and is driven by a motor, which is 
supplied with current by a special local battery and 
a primary condenser. The current is next led 
through the primary by an inductor, a special form 
of induction coil having a large core and a very 
heavy winding on the secondary circuit. The cur- 
rent now passes through a secondary condenser to 
adjustable series and parallel spark-gaps. The elec- 
tric waves generated by this arrangement are taken 

294 prospector's field-book and guide. 

to earth by means of two iron spikes driven two to 
three inches into the ground. 

The receiving set comprises two similar iron 
spikes, driven into the ground to a depth of an inch 
or two, and connected up to a tripod on which are 
placed a series parallel and with a transformer and 
two delicate receivers or resonators. The inter- 
rupter breaks contact 700 times a minute. 

By adjusting his earth connections the operator 
can focus the waves on any field that he may wish 
to explore ; the lines of force travel outward and 
onward until they reach the iron spikes in the re- 
ceiving set. When this occurs, the observer can by 
means of the resonators detect their presence by 
hearing the noise of the break, or by the sparking 
across the gaps. 

Now, in a normal condition, i. e., if the ground 
be of a homogeneous character, the prospector 
should hear the noises loudest when exactly oppo- 
site the center of the base line of the transmitting 

The existence, however, of a vein or reef contain- 
ing metal has the tendency of throwing the waves 
out of normal course, by reason of the fact that it 
has a different conductivity from the material by 
which it is surrounded. The prospector must there- 
fore make his earth connections in different places, 
and shift his position until he can detect the pres- 
ence of the waves. When directly over the lode, 
the noise in the resonators will be loudest. 

Condenser-discharges from lodes manifest them- 


selves as overtones in the receivers, and at certain 
spots or nodal points the noise will cease altogether 
owing to the influence of the waves. 

The condenser-discharges can be heard over some 
lodes when the distance from the inductor is so great 
that the noise of the break or of the spark-gap can- 
not be heard ; thus they form a great assistance to 
prospecting, helping to determine not only the posi- 
tion and depth of a mineral deposit, but also, to a 
great extent, its nature and characteristics. 

The area to be energized by the electrical waves 
may be as small as 300 square feet and as large as 
30 square miles, and the terminals may be placed 
hundreds of yards apart. 

It will, of course, be necessary to train mining 
engineers and prospectors in the use of the instru- 
ments and in the detection of the presence of the 
waves. The whole outfit is, however, simple and 
easy to work with. Its development during the 
next few years will be watched with interest by all 
interested in mining operations. 


British weights and measures, and those used in 
our country, are based upon the weight of a cubic 
inch of distilled water at 62° Fall., and 30 inches 
height of the barometer, the maximum density. 
This was decided by Parliament, in the reign of 
George IV., to be 252.458 grains. Recent experi- 
ments, however, show that a cubic inch of water at 

the temperature of maximum density is 252.286 
standard grains. On this account scientists are 
urging the readjustment of the gallon, bushel, etc., 
but at present the tables below are correct. See also 
No. 8. 

Weights and measures of various nations : — 

No. 1. — English Length. 

3 barleycorns = 1 inch. 

12 inches = 1 foot. 

3 feet = 1 yard. 

5£ yards = 1 rod, pole, or perch (16J feet). 

4« poles or 100 links = 1 chain (22 yards or 66 feet). 
10 chains = 1 furlong (220 yards or 660 feet). 

8 furlongs = 1 mile (1760 yards or 5280 feet). 

A span = 9 inches ; a fathom = 6 feet ; a league = 3 miles ; a 
geographical mile = 6082.66 feet, same as nautical knot, 60 being a 
degree, i. e., 69.121 miles. 

Particular Measures of Length. 

A point, 7 \ of an inch. A pace, military, 2 feet, 6 inches. 

A line, j 1 ^ of an inch. A pace, geometrical, 5 feet. 

A palm, 3 inches. A cable's length, 120 fathoms. 

A hand, 4 inches. A degree (average), 69^ miles. 
A link, 7.92 inches. 

No. 2. — Surface Measure. 

144 square inches = 1 square foot. 

9 square feet =b 1 square yard. 

30^ square yards = 1 pole, rod, or perch (square). 

16 poles (square) = 1 chain (sq.) or 484 sq. yds. 

40 poles = 1 rood (sq.) or 1210 sq. yds. 

10 chains or 4 roods = 1 acre (4840 sq. yds.). 

640 acres = 1 sq. mile. 


No. 3. — Surface 

Measure in Feet. 

9 square feet 


1 square yard. 

272i " " 


1 pole, rod, or perch. 

4,356 " " 


1 square chain. 

10,890 *t i( 


1 square rood. 

43,560 " " 


1 acre. 

27,878,400 " " 


1 square mile. 


No. 4. — Solid Measure. 

1728 cubic inches = 1 cubic foot. 
27 cubic feet = 1 cubic yard. 
16 j feet long, 1 foot high, and H feet thick — 1 perch stone = 
24f cubic feet. 

No. 5. — Troy Weight. 
Platinum, gold, silver, and some precious stones 
are weighed by Troy weight, diamonds by carats 
of 4 grains each. 

24 grains 

20 pennyweights 

12 ounces 

No. 6.- 

16 drams 
16 ounces 
14 pounds 

2 stones 

4 quarters 
20 hundred-weight 

= 1 pennyweight. 

= 1 ounce (480 grains). 

= 1 pound (5760 grains). 

-Avoirdupois Weight. 

= 1 ounce (437-J grains). 
= 1 pound (7000 grains). 
= 1 stone. 
= 1 quarter. 

1 hundred-weight (112 pounds). 

1 ton (long ton) (2240 pounds). 

No. 7. — Weight by Specific Gravity. 
Frequently the weight of masses is required 
where it is very inconvenient, or, perhaps, impos- 
sible to use scales. The following method may be 
sufficiently accurate : — 

298 prospector's field-book and guide. 

Find the average specific gravity of the mass 
either by actual weight of a piece or by the follow- 
ing table. Then measure the cubic contents of the 
mass as nearly as possible and multiply by the 
weight of a cubic foot. Thus, a mass of limestone 
(say good marble) measures 40 cubic feet. The 
specific gravity of good marble is 2.6, that is, it is 
2.6 as heavy as a cubic foot of water, which weighs 
62.5 pounds. Therefore 62.5 



A cubic foot of good marble weighs 162.5 pounds, 
and the 40 cubic feet will weigh 162.5 


or about 3| tons. Of course all rock masses have 
not plane sides, and the irregularity requires some 
calculation and various allowances which the pros- 
pector must make, and can easily do with a little 

When greater accuracy of specific gravity and of 
bulk is desired for small masses, and no scales are 
at hand, the following plan may be very satisfac- 
torily adopted. Fill a tub or hogshead or large box 
with rain water, after having inserted a tube or 
piece of tin pipe into the upper edge. Pour in more 
water until it will hold no more without running 


out of the spout. Introduce the mass of rock and 
catch all the water which runs out of the pipe. 
Now measure the overflow ; this represents the 
exact cubic measure of the rock introduced. 

1 gallon contains 231 cubic inches. 

1 quart " 57.75 or 57f cubic inches. 

1 pint " 28.87 or 28| " " 

1 gill " 7.21 or 7| " 

See Appendix, No. 8. 

Suppose the overflow was 8 gallons, 1 quart, 4J 
gills, and that the specific gravity of the rock or ore 
was 6.5 by the table below. Then the mass will 
cause an overflow of 1936.99 cubic inches, and this 
is 208.99 more than one cubic foot, or about 1.120 
of a cubic foot for the mass. 

Since 6.5 was the specific gravity of the ore, 
6.5x62.5 pounds = 406.25, which would be the 
weight of a cubic foot of the ore, and 406.25 x 1.120 
= 455 pounds, the exact weight of the mass you 
introduced into the water. 

Specific Gravity, how to Find. Where the 
mass is of very nearly the same density in all parts, 
the specific gravity may be taken of a small part as 
follows : 

Suspend the scales so that they will be steady 
weigh about an ounce or pound of the ore accu- 
rately, then tie the ore by a horse-hair or a fine silk 
thread to the hook that holds one of the scales, and 
let it (the ore) hang below the scale pan, and then 
weigh the ore entirely submerged in water. The 
thread or hair may be attached to the centre of the 

300 prospector's field-book and guide. 

scale pan and weighed in that way, but the pan in 
either case must remain on the scales just as before. 
Then the weight in air divided by the weight in air 
minus the weight in water, is the specific gravity ; 
e. g.j a piece of ore weighs in air 100 grains, in 
water 80 grains, then 100 divided by (100—80 = 
20) = 5, the specific gravity of that piece of ore. 
You may now proceed as in the case of the marble 

No. 8. — Special Weights, etc. 

One cubic foot of water is equal to 7.475 U. S. 
gals, of 231 cubic inches each, or 7J gallons nearly ; 
or 6.2321 Imperial gals, of 277^ cubic inches each. 
This, with what follows, is important in the con- 
struction of tanks, pools, etc., where contents, 
weight, and pressure are to be considered. 

It should be remembered that, although the Eng- 
lish Imperial gallon is 277 J cubic inches = 10 lbs. 
avoir, of distilled water at 62° Fah., Bar. 30 inches, 
and equal to 277.274 cubic inches, the United States 
standard gallon is 231 inches, or 58372.1754 grains, 
or 8.3389 lbs. of distilled water maximum density. 
This is almost exactly = to a cylinder 7 inches 
diameter, 6 inches high. The beer gallon = 282 

One gallon = 8.3389 lbs.; one quart = 2.0847 
lbs.; one pint = 1.0423 lbs.; one gill = 0.2606 lb., 
U. S. standard measure. One cubic foot of water 
= 62.3210 lbs., British weight; recent and correct, 



No. 9. — French Measures. — Length. 

Millimetre ( j^^ of a metre) 
Centimetre ( r f - " " 
Decimetre ( T X o " " 

Metre (the unit of length) 
Decametre (10 metres) 
Hectometre (100 metres) 
Kilometre (1000 metres) 
Myriametre (10,000 metres) 

.03937 inch. 
.3937 " 
39.3708 " or 3.2809 ft. 
32.809 ft. or 10.9363 yds. 
109.3633 yards. 
1093.63 yds. or .62138 mile. 
6.2138 miles. 


Centiare ( j^ of an are or sq. metre 
Are (unit of surface) 

Decare (10 ares) 

Hectare (100 ares) 

- { 

1.1960 sq. yds. 
119.6033 sq. yards or 

.0247 acre. 
1196.033 sq. yards or 

.2474 acre. 
11960.33 sq. yards or 

2.4736 acres. 

Solid Measure. 

Decistere (y 1 ^ of a stere) 
Stere (cubic metre) 
Decastere (10 steres) 

= 3.5317 cubic feet. 
= 35.3166 " " 
= 353.1658 " " 


Milligramme ( T o X oo °f a gramme) = .0154 grain. 

Centigramme ( T ^ 
Decigramme (y^ 
Gramme (unit of weight) 
Decagramme (10 grammes) 

) — .1544 grain. 
) = 1.544 grains. 

==■ 15.44 grains. 

== 154.4 grains. 

1,544 grains. 

Hectogramme (100 " ) 

Kilogramme (1000 wt ) 

Myriagramme (10,000 grammes) — 22.057 pounds. 

f 3.2167 ozs. 
j Troy or 
■ 3.5291 ozs. 
L Avoir. 

= 32£ ozs. or 2.2057 pounds. 

302 prospector's field-book and guide. 

No. 10. — Specific Gravity of Metals, 
Ores, Rocks, etc. 

Platinum 16-21 

Gold 16-19.5 

Mercury 13.5 

Lead 11.35-11.5 

Silver 10.1-11.1 

Copper 8.5-8.9 

Iron when pure 7.78 

Iron, cast, average 6.7; foundry 6.9 to 7 

Ores : associated with gold and silver. 

(Gold) Iron pyrites 4.8-5.2 

Copper pyrites 4.0-4.3 

(Silver) Galena 7.2-7.7 

Glance (silver) 7.2-7.4 

Euby silver (dark) 5.7-5.9 

" (light) 5.5-5.6 

Brittle silver (sulphide) 5.2-6.3 

Horn silver 5.5-5.6 

Other Ores. 

Zinc blende 3.7-4.2 

Mercury (Cinnabar) 8.8-9.9 

Tin — tinstone, cassiterite 6.4-7.6 

Tin pyrites 4.3-4.5 

Copper — Red or ruby copper 5.7-6.15 

Gray. . 5.5-5.8 

Black oxide 5.2-6.3 

Pyrites 4.1-4.3 

Carbonate (Malachite) 3.5-4.1 

Lead — sulphide (Galena) 7.2-7.7 

Carbonate (white lead) 6.4-6.6 

Zinc— Blende 3.7-4.2 

Calamine 4.0-4.5 

Iron— Hematite (red) • • • .4.5-5.3 

Magnetic 4.9-5.9 

Brown hematite 3.6-4.0 

Spathic (carbonate) 3.7-3.9 

Pyrites (mundic) 4.8-5.2 


Antimony — gyray sulphide 4.5-4.7 

Nickel — Kupfer nickel 7.3-7.5 

Cobalt— Tin-white 6.5-7.2 

Glance 6.0 

Pyrites 4.8-5 

Bloom 2.91-2.95 

Earthy 3.15-3.29 . 

Manganese — Black oxide 4.7-5.0 

Wad, Bog manganese 2.0-4.6 

Bismuth— Sulphide , 6.4-6.6 

Oxide 4.3 

Minerals of Common Occurrence. 

Quartz 2.5-2.8 

Fluorspar 3.0-3.3 

Calc spar 2.5-2.8 

Barytes 4.3-4.8 

Granite \ 2 4_2 7 

Gneiss / 

Mica slate 2.6-2.9 

Syenite 2.7-3.0 

Greenstone trap 2.7-3.0 

Basalt 2.6-3.1 

Porphyry 2.3-2.7 

Talcose slate 2.6-2.8 

Clay slate 2.5-2.8 

Chloritic slate 2.7-2.8 

Serpentine 2.5-2.7 

Limestone and Dolomite 2.5-2.9 

Sandstones 1.9-2.7 

Shale 2.8 

Other minerals are mentioned in the text with their specific 

No. 11. — A Ton Weight of the Following will 
Average in Cubic Feet : 

Earth 21 cubic feet. Pit sand 22 cubic feet. 

Clay 18 " " Biversandl9 " " 

Chalk 14 " " Marl 18 " " 

Coarse gravel 19 " " Shingle 23 " " 

304 prospector's field-book and guide. 

Assay -of Gold by the Touchstone.* 

This is a rough and rapid method of approxi- 
mately ascertaining the quality of a gold alloy 
without injury to the article, as is the case in dry 
and wet assaying. 

An experienced person may determine the correct 
standard within 1 per cent, of the truth. The method 
is based on the fact that the richer an alloy is in 
gold, the more clearly does a streak drawn with it 
on a black ground exhibit a pure golden yellow 
color, and the less it is attacked by a test acid. 

The touchstone is a hard siliceous stone of a black 
color, its surface being prepared and left so that it 
will just abrade the metal from any sharp angle of 
the alloy when the latter is drawn over the stone. 

In order to ascertain the quality of the alloy, its 
streak is compared with streaks drawn by alloys of 
known fineness, called touch 'needles, of which five 
series are required. 

1. Red series, consisting of gold and copper, the 
gold increasing by half carats in successive needles. 

2. White series contains gold and silver. 

3. Mixed series, in which the quantities of silver 
and copper alloyed with the gold are equal. 

4. Unequal mixed series, in which the silver is to 
the gold as 2 : 1. 

5. Series in which the silver is to the copper as 

*From Hiorns's "Practical Metallurgy and Assaying." 


Besides these, special needles are prepared for dif- 
ferent kinds of work. 

The mark left on the stone by the alloy having 
been matched with the corresponding mark of one 
of the touch needles it is assumed to have the same 
composition. To confirm this assumption, a drop 
of acid is placed on each streak, allowed to work for 
some time, and its effect observed in each case, then 
wiped off to see if the mark is left unchanged. 

The test acid consists of : 98 parts pure nitric acid, 
2 parts hydrochloric acid, 25 parts distilled water. 

The first streak made by a body is discarded, as 
in the case of colored gold, for example, the surface 
having a different composition to the general mass. 

The above test mixture has no effect on alloys of 
18 carats and upwards, so that streaks made by 
these alloys will not be wiped off with a linen rag 
after treating with acid. Pure nitric acid has no 
effect on alloys of 15 carats upwards. 

Estimation of Gold in Alloys (Hiorns). 

In places where a large number of assays have to 
be conducted a special set of weights is employed, 
as with silver, the unit quantity being termed the 
assay pound, which is subdivided into carats, carat 
grains, eights, and excess grains. The amount 
taken as a unit may be 10 grains or half a gramme 
=s 7.716 grains. The relation of the parts are 
well shown in the following table by Prof. Roberts- 
Austen : 

306 prospector's field-book and guide. 



























The excess grains in one assay pound are the 
same as the number of grains in the troy pounds. 

Gold is reported to the trade according to the 

above table, in carats or the decimal equivalents. 

Thus pure gold is 24 carats or 1000 fine ; standard 

22 x 1000 
gold, 22 carats = ^ = 916.66 fine. 

When an alloy is slightly " worse " than the 
standard, it is said to be " worse so much." When 
above the standard, the alloy is called " better so 
much," the difference being expressed in carat 
grains, eights, and excess grains, or in its decimal 



equivalent. In both cases the excess grains repre- 
sent gold present in excess of the report. 

Standard Values of Gold in Different 


England \ 

(one troy ounce) / 

United States . . . \ 
(one troy ounce) J 

France (Kilogramme), 

Germany ' ' 

(24 carats). 

£4 4 10 


Fr. 3,444.44 
Mk. 2,790 

(22 carats). 

£3 17 10 


Fr. 3,157.40 

(21.6 carats). 

£3 16 6 


Fr. 3,100 
Mk. 2,511 

Power for Mills. 

As the Pelton wheel seems to find the most fre- 
quent application in California, it may be conveni- 
ent to have the following rule, applicable to this 
wheel : 

When the head of water is known in feet, multi- 
ply it by 0.0024147, and the product is the horse- 
power obtainable from one miner's inch of water. 

The power necessary for different mill parts is : 

For each 850 lbs. stamp, dropping 6 inches 95 times per 

minute 1.33 H. P. 

For each 750 lbs. stamp, dropping C inches 95 times per 

minute 1.18 " 

For each 650 lbs. stamp, dropping 6 inches 95 times per 

minute . . 1.00 " 

For an 8-inch by 10-inch Blake pattern rock breaker .9.00 " 
For a Frne or Triumph vanner with 220 revolutions per 

minute 0.50 " 

308 prospector's field-book and guide. 

For a 4-foot clean-up pan, making 30 revolutions per 

minute 1.50 H. P. 

For an amalgamating barrel, making 30 revolutions per 

minute 2.50 " 

For a mechanical batea, making 30 revolutions per 

minute 1.00 " 

Rock is bored with jumpers of 10 to 18 lbs., used 
alone or with boring bars and hammer. The 
former are more effective, but can only be used 
perpendicularly, or nearly so, and with rock of 
moderate hardness ; they require more skill. 

18 lb. hammers are used for 3 inch boring bars. 
16 lb. " " " 2 j inch boring bars. 

14 1b. " l< k ' 2 and If inch boring bars. 

5 to 7 lb. " " " 1 inch boring bars. 

The boring bars may be made of lj-inch bar 
iron of various lengths, with steel bits up to 3 
inches. A bit should bore from 18 to 24 feet with 
each steeling, and requires to be sharpened once for 
every foot bored. 

Diamond Drill. 

This drill is applicable to sinking a bore-hole for 
prospecting for minerals or water, shafts, etc., or 
blasting under water. 

It consists of a circular row of " carbonados," a 
species of diamond, set in a circular steel ring. 
This is attached to a hollow steel tube, which is 
kept rotating at about 250 revolutions per minute, 
pressed forward by a force varying from 400 to 800 
lbs., according to the nature of the rock. Water is 



supplied through the tube, which washes out the 
debris and cools the diamonds. 

Granite and the hardest limestones are penetrated 
at the rate of 2 or 3 inches per minute, sandstones 
4 inches, quartz 1 inch. 

The diamond drill is not effective in soft strata, 
such as clay, sand and alluvial deposits. 

The Chemical Elements, their Symbols, Equiva- 
lents and Specific Gravities. 


Aluminium . 
Antimony . . 
Arsenic . 
Barium . . . - 
Bismuth . . • 

Cadmium . . . 
Caesium . ... 
Calcium . 
Carbon . ... 
Cerium . . . 

Chlorine . . . 
Chromium ... 
Cobalt .... 


Didymium . . . 


Fluorine .... 
Gallium . 
Glucinum . 
Gold (Aurum) . . 
Hydrogen .... 
Indium . ... 


Iridium . 
Iron (Ferrum) . 
Lanthanum . 
Lead (Plumbum) 
















































































! 127.0 



; 198.0 



! 56.0 




11 37 


! 207.0 


310 prospector's field-book and guide. 

The Chemical Elements, their Symbols, Equiva- 
lents and Specific Gravities. 





Mercury (Hydrargyrum) 






Oxygen ....... 



Platinum . .... 

Potassium (Kalium) . - 






Silver (Argentum) . . . 
Sodium (Natrium) . . . 







Tin (Stannum) .... 


Tungsten (Wolfram) . . 


















































































































The figures indicating the proportions by weight 
in which the elements unite with one another are 


called the combining or atomic weights, because they 
represent the relative weights of the atoms of the 
different elements. Since hydrogen is the lightest 
element, it is taken as the standard, and its combin- 
ing or atomic weight = 1. 

To find the proportional parts by weight of the ele- 
ments of any substance whose chemical formula is 
known : 

Rule. — Multiply together the equivalent and the 
exponent of each element of the compound ; the 
product will be the proportion by weight of that 
element in the substance. 

Example. — Find the proportionate weights of the 
elements of alcohol, C 2 H 6 : ' 

Carbon C a = equivalent 12 X exponent 2 = 24 
Hydrogen H 6 = " IX " 6= 6 

Oxygen O =■■ " 16 X " 1 — 16 

Of every 46 lbs. of alcohol, 6 lbs. will be H ; 16 ; 
24 C. 

To find the proportions by volume, divide by the 
specific gravity. 

Common Names of Chemical Substances. 
Common Names. Chemical Names. 

Aqua fortis. Nitric acid. 

Aqua regia. Nitro-hydrochloric acid. 

Blue vitriol. Sulphate of copper. 

Cream of tartar. Bitartrate of potassium. 

Calomel. Chloride of mercury. 

Chalk. Carbonate of calcium. 

Caustic potash. Hydrate of potassium. 

Chloroform. Chloride of formyl. 



Common salt. 

Copperas and green vitriol. 
Corrosive sublimate. 
Dry alum. 

Epsom salts. 

Ethiops mineral. 


Glauber 1 s salt. 


Iron pyrites. 

Jeweler's putty. 

King's yellow. 

Laughing gas. 


Lunar caustic. 

Mosaic gold. 

Muriate of lime. 

Muriatic acid. 

Nitre or saltpetre. 

Oil of vitriol. 



Red lead. 

Rust of iron. 

Sal ammoniac. 

Salt of tartar. 

Slaked lime. 


Spirits of hartshorn. 

Spirits of salt. 

Stucco or plaster of Paris. 

Sugar of lead. 




Volatile alkali. 


White precipitate. 

White vitriol. 

Chloride of sodium. 
Sulphate of iron. 
Bichloride of mercury. 
Sulphate of aluminium and potas- 
Sulphate of magnesium. 
Black sulphide of mercury. 
Sulphide of lead. 
Sulphate of sodium. 
Grape sugar. 
Bisulphide of iron. 
Oxide of tin. 
Sulphide of arsenic. 
Protoxide of nitrogen. 
Oxide of calcium. 
Nitrate of silver. 
Bisulphide of tin. 
Chloride of calcium. 
Hydrochloric acid. 
Nitrate of potash. 
Sulphuric acid. 
Oxide of potassium. 
Sulphide of arsenic. 
Oxide of lead. 
Oxide of iron. 
Chloride of ammonia. 
Carbonate of potassium. 
Hydrate of calcium. 
Oxide of sodium. 
Hydrochloric acid. 
Sulphate of lime. 
Acetate of lead. 
Basic acetate of copper. 
Sulphide of mercury. 
Acetic acid (diluted). 
Oxide of hydrogen. 
Ammoniated mercury. 
Sulphate of zinc. 




Take a soft pine board, and a hard lead pencil, 
and the writing will sometimes outlast your claim. 
I have seen such notices that have withstood the 
storms of seven or eight years and still remain 
legible. There is a great variety of ways to write 
a notice ; and nearly every prospector has his own 
way. But the briefest and most concise way is as 
good as any, and the easiest. Now, I'll write you 
one for the Catharine this way : 

Catharine Lode. 

Notice is hereby given that I, the undersigned 
citizen of the United States, having complied with 
Chapter 36, Title 32, Revised Statutes of the United 
States, and the local regulations of Barker district, 
claim by right of discovery, 1500 feet in length, and 
600 feet in width, along the mineral-bearing vein, 
to be known as the Catharine (or any other name). 

Beginning at centre of discovery shaft and run- 
ning : " How far do you run northerly ? " 

" Seven hundred feet northeast." 

" Seven hundred feet in a northerly direction and 
800 feet in a southerly direction. 

" Always say northerly, southerly, easterly, and 
westerly in writing notices. Don't give it any spe- 
cific direction. When you say ' northerly,' it gives 


you a chance to swing your stakes all round the 
North Pole, if necessary. You can swing your 
stakes after your location is made any way you 
want to, provided there are no conflicting claims, 
unless you change from northerly and southerly to 
easterly and westerly, or vice versa. In that case, 
you have to make an amended location and record 
it. Let's see. Where were we ? Oh, yes ; together 
with 300 feet on either side of the vein. 
"Located this 18th day of June, 1891." 
" Locator — Tenderfoot, Prospector." 
Now that is all that is necessary to hold any 
claim, as far as the notice goes. Some prospectors 
put in a claim for all dips, spurs, angles, and varia- 
tions throughout the width, breadth and depth of 
the claim ; but that's all foolishness. The law 
grants you all the spurs and angles and dips you 
want. You just go ahead and do as the law re- 
quires you to do, to hold any mining claim." — 
Butte Bystander. 




Abraded. Reduced to powder. 

Acicular. Needle-shaped. 

Adamantine. Of diamond lustre. 

Adit. A nearly horizontal passage from the surface by which a 
mine is entered. In the United States an adit is usually called a 

Aerolite. A stone or other body which has come to the earth from 
distant space. 

Agate. Name given to certain siliceous minerals. 

Aggregation. A coherent group. 

Alligator. A rock-breaker operating by jaws. 

Alloy. A compound of two or more metals fused together. 

Alluvium. The earthy deposit made by running streams, especi- 
ally in times of Hood. 

Amalgamation. The production of an amalgam or alloy of mer- 
cury; also the process in which gold and silver are extracted from 
pulverized ores by producing an amalgam from which the mercury 
is afterwards expelled. 

Amorphous. Without any crystallization or definite form. 

Amygdaloid*. Small almond-shaped vesicular cavities in certain 
igneous rocks, partly or entirely filled with other minerals. 

Analysis (in Chemistry). An examination of the substance to find 
out the nature of tiie component parts and their quantities. The 
former is called qualitative and the latter quantitative analysis. 


316 prospector's field-book and guide. 

Anemometer. An instrument for measuring the rapidity of an air- 

Anticlinal. The line of a crest, above or under ground, on the 
two sides of which the strata dip in opposite directions. The con- 
verse of synclinal. 

Apex. In the U. S. Revised Statutes, the end or edge of a vein 
nearest the surface. 

Aqua for 'tis. Name formerly applied to nitric acid. 

Aqua regia. A mixture of nitric and hydrochloric acids. One 
volume of strong nitric to three or four of hydrochloric acid is a 
good mixture. 

Arborescent. Of a tree-like form. 

Arenaceous. Siliceous or sandy (of rocks). 

Argentiferous. Containing silver. 

Argillaceous. Containing clay. 

Arrastre. Apparatus for grinding and mixing ores by means of a 
heavy stone dragged around upon a circular bed. Chiefly used for 
ores containing free gold. 

A rsenite. Compound of a metal with arsenic. 

Assay. To test ores and minerals by chemical or blow-pipe ex- 

Assay-ton. A weight of 29.166f grammes. 

Assessment-work. The work done annually on a mining claim to 
maintain possessory title. 

Auriferous. Containing gold 

Axe Stone. A species of jade. It is a silicate of magnesia and 

Back of a lode. The part between the roof and the surface. 

Back-shift. The second set of miners working in any spot each 

Bank claim. A mining claim on the bank of a stream. 

Banket. Auriferous conglomerates cemented together with quartz. 

Bar. A vein or dike crossing a lode ; also a sand or rock ridge 
crossing the bed of a stream. 

Bar-diggings. Gold-washing claims located on ihe bars (shallows) 


of a stream, and worked when the water is low, or otherwise with 
the aid of coffer-dams. 

Barilla. Native copper disseminated in grains in copper ores. 

Barrel-amalgamation. The amalgamation of silver ores in wooden 
barrels with quicksilver, metallic iron, and water. 

Base metals. The metals not classed as noble or precious. See 
Noble metals. 

Bases. Compounds which are converted into salts by the action 
of acids. 

Basin. A natural depression of strata containing a coal bed or 
other stratified deposit; also the deposit itself. 

Battery. A set of stamps in a stamp mill comprising the number 
which fall in one mortar, usually five; also a bulkhead of timber. 

Battery-amalgamation. Amalgamation by means of mercury placed 
in the mortar. 

Bed. A seam or deposit of mineral, later in origin than the rock 
below, and older than the rock above; that is to say, a regular mem- 
ber of the series of formation, and not an intrusion. 

Bedded-vein. A lode occupying the position of a bed, that is, 
parallel with the stratification of the inclosing rocks. 

Bed-rock. The solid rock underlying alluvial and other surface 

Bed-way. An appearance of stratification, or parallel marking, in 

Belly. A swelling mass of ore in a lode. 

Black band. A variety of carbonate of iron. 

Black flux. A mixture of charcoal and potassium carbonate 

Blackjack. Zinc-blende. 

Black tin. Tin ore ready dressed for smelting. 

Blanch. Lead ore mixed with other minerals. 

Blanched copper. An alloy of copper and arsenic. 

Blende. Sulphide of zinc. 

Blind level. A level not yet connected with other \rorkings. 

Blind lode, One that does not show surface croppings. 

Blossom. The oxidized or decomposed outcrop of a vein or coal 
bed. Also called smut and (ailing. 

318 prospector's field-book and guide. 

Blow-out. 1. A large outcrop beneath which the vein is smaller. 
2. A shot or blast is said to blow out when it goes off like a gun, and 
does not shatter the rock. • 

Blue-john. Fluorspar. 

Blue lead. The bluish auriferous gravel and cement deposit found 
in the ancient river-channels of California. 

Bluff. A high bank or hill with a precipitous front. 

Bonanza. A body of rich ore. 

Booming. The accumulation and sudden discharge of a quantity 
of water (in placer-mining, where water is scarce). See also Hushing. 

Bort. Opaque black diamond. 

Botryoidal. Like a bunch of grapes. 

Boulder. A fragment of rock brought by natural means from a 
distance, and usually large and rounded in shape. 

Brasque. A lining for crucibles; generally a compound of clay, 
etc., with charcoal dust. 

Breast. The face of a working. 

Breccia. A conglomerate in which the fragments are angular. 

Buddie. An inclined vat, or stationary or revolving platform 
upon which ore is concentrated by means of running water. 

Bullion. Uncoined gold and silver. Base bullion is pig lead con- 
taining silver and some gold, which are separated by refining. 

Buried rivers. .River beds which have been buried below streams 
of basalt or alluvial drifts. 

Burr. Solid rock. 

Button. The globule of metal remaining in a crucible at the end 
of fusion. 

Cage. A frame with one or more platforms used in hoisting in a 
vertical shaft. 

Cairngorm. A variety of quartz, frequently transparent; used as 
an ornament. 

Calcareous. Containing carbonate of lime. 

Calcination. Roasting at a gentle heat. 

Calcine. To expose to heat with or without oxidation. 

Calcite. Carbonate of lime. 


Canon. A valley, usually precipitous; a gorge. 

Cap or cap-rock. Barren vein matter, or a pinch in a vein, sup- 
posed to overlie ore. 

Carat. Weight, nearly equal to four grains, used for diamonds 
and precious stones. With goldsmiths and assayers the term carat 
is applied to the proportions of gold in an alloy; 24 carats represents 
fine gold. Thus 18 carat gold signifies that 18 out of 24 parts are 
pure gold, the rest some other metal. 

Carbonaceous. Containing carbon not oxidized. 

Carbonates. The common term in the West for ores containing a 
considerable proportion of carbonate of lead. 

Carbonization. Conversion to carbon. 

Case. A small fissure admitting water into the workings. 

Casing. Clayey material found between a vein and its wall. 

Cawk. Sulphate of baryta (heavy spar). 

Cement. Gravel firmly held in a siliceous matrix, or the matrix 

Champion lode. The main vein as distinguished from branches. 

Chasing. Following a vein by its range or direction. 

Chert. Hornstone; a siliceous stone often found in limestone. 

Choke damp. Carbonic acid gas. 

Chlorides. A common term for ores containing chloride of silver. 

Chloridize. To convert into chloride. Applied to the roasting of 
silver ores with salt, preparatory to amalgamation. 

Chute. A channel or shaft underground, or an inclined trough 
above ground, through which ore falls or is " shot" by gravity from 
:a lower to a higher level. 

Claim. The portion of mining ground held under the Federal 
;and local laws by one claimant or association, by virtue of one loca- 
tion and record. 

Clay slate. A slate formed by the induration of clay. 

Cleavage. The property of a mineral of splitting more easily in 
some directions than in others'. 

Cleavage planes. The planes along which cleavage takes place. 

Clinometer. An apparatus for measuring vertical angles, particu- 
larly dips. 

320 prospector's field-book and guide. 

Cobre ores. Copper ores from Cuba. 

Oolor. A particle of gold found in the prospector's pan. 

Concentration. The removal by mechanical means of the lighter 
and less valuable portions of ore. 

Conchoidal. Name given to a certain kirid of fracture resembling 
a bivalve shell. 

Concretion. A nodule formed by the aggregation of mineral mat- 
ter from without round some centre. 

Conglomerate. A rock consisting of fragments of other rocks (usu- 
ally rounded) cemented together. 

Consume. The chemical and mechanical loss of mercury in amal- 

Contact. The plane between two adjacent bodies of dissimilar 
rock. A contact-vein is a. vein, and a contact-bed is a bed, lying, the 
former more or less closely, the latter absolutely, along a contact. 

Contortion. Crumpling and twisting. 

Coprolites. Phosphate of lime; petrified excrements of animals. 

Counter. A cross vein. . 

Country, or Country rock. The rock traversed by or adjacent to 
an ore deposit. 

Course of a lode. Its direction. 

Cradle. See Rocker. 

Cranch. Part of a vein left by old workers. 

Urate dam. A dam built of crates filled with stone. 

Crater. The cup-like cavity at the summit of a volcano. 

Cretaceous. Chalky. 

Crevet. A crucible. 

Crevice. A shallow fissure in the bed-rock under a gold placer, 
in which small but highly concentrated deposits of gold are found; 
also the fissure containing a vein. 

Cribbing. Close timbering, as the lining of a shaft. 

Cribble. A sieve. 

Cropping-out. The rising of layers of rock to the surface. 

Cross-course. An intersecting (usually), a barren vein. 
-cut. A level driven across the course of a vein. 


Cross-vein. An intersecting vein. 
Cupriferous. Containing copper. 

Cyanidation. Conversion of gold into a double cyanide of potas- 
sium and gold by the action of cyanide of potassium. 

Dead-roosting. Roasting carried to the farthest practicable degree 
in the expulsion of sulphur. 

Bead-work. Work that is not directly productive, though it may 
be necessary for exploration and future production. 

Debris. The fragments resulting from shattering and disintegra- 

Decrepitate. To crackle and fly to pieces when heated. 

Deep Leads. Alluvial deposits of gold or tinstone buried below a 
considerable thickness of soil or rock. 

Delta. The alluvial land at the mouth of a river; usually bounded 
by two branches of the river, so as to be of a more or less triangular 

Dendritic. Like branches of trees. 

Denudation. Rock laid bare by water or other agency. 

Deoxidation. The removal of oxygen. 

Desilverization. The process of separating silver from its alloys. 

Desvlphurization. The removal of sulphur from sulphuret ores. 

Detritus. Accumulations from the disintegration of exposed rock 

Development. Work done in opening of a mine. 

Dialling. Surveying a mine by means of a dial. 

Diggings. Applicable to all mineral deposits and mining camps^ 
but in usage in the United States applied to placer-mining only. 

Dike. A vein of igneous rock. 

Diluvium. Sand, gravel, clay, etc., in superficial deposits. 

Dip. The inclination of a vein or stratum below the horizontal. 

Disintegration. The breaking asunder of solid matter due to 
chemical or physical forces. 

Dislocation. The displacement of rocks on either side of a crack. 

Divining rod. A rod, most frequently of witch-hazel, and forked 


322 prospector's field-book and guide. 

in shape, used according to an old but still extant superstition for 
discovering mineral veins and springs of water, and even for locating 
oil wells. 

Discovery. The first finding of the mineral deposit in place upon 
a mining claim. A discovery is necessary before the location can be 
held by a valid title. The opening in which it is made is called 
discovery -shaft, discovery-tunnel, etc. 

Ditch. An artificial water-course, flume or canal to convey water 
for mining. 

Dolly. An apparatus used in washing gold-bearing rocks (Aus- 

Domes. Strata which are dipping away in every direction. 

Drift. A horizontal passage underground ; also unstratified dilu- 

Druse. A crystallized crust lining the sides of a cavity. 

Dry ores. Silver ores which do not contain lead. 

Dyke. See Dike. 

Efflorescence. An incrustation of powder or threads, due to the 
loss of the water of crystallization. 

Elements. Substances which have never been decomposed. 

Elutriation. Purification by washing and pouring off the lighter 
matter suspended in water, leaving the heavier portions behind. 

Entry. An adit. 

Erosion. The act or operation of wearing away. 

Excrescence. Grown out from something else. 

Exfoliate. To peel off in leaves from the outside. 

Exploitation. The productive working of a mine as distinguished 
from exploration. 

Face. In any adit, tunnel, or slope, the end at which work is 
progressing or was last done. 

False Bottom. In alluvial mining a stratum on which auriferous 
beds lie, but which has other bottoms below it. 

Fathom. 6 feet. 

Fault. A dislocation of the strata or vein. 


Feather Ore. A sulphide of lead and antimony. 

Feeder. A small vein adjoining a larger vein. 

Feldspathie. Containing feldspar as the principal ingredient. 

Ferruginous. Containing iron. 

Fire-damp. Light carburetted hydrogen gas. 

Fissure-vein. A fissure in the earth's crust filled with mineral. 

Flexible. Capable of being bent without elasticity. 

Flint. A massive impure variety of silica. 

Float-copper. Fine scales of metallic copper which do not readily 
settle in water. 

Float-gold. Fine particles of gold which do not readily settle 
in water, and hence are liable to be lost in the ordinary stamp-mill 

Float-ore. Water- worn particles of ore; particles of vein -material 
found on the surface, away from the vein outcrop. 

Flocculent. Cloudy, resembling lumps of wool. 

Floor. The rock underlying a stratified or nearly horizontal de- 
posit, also a horizontal flat ore body. 

Flume. A wooden conduit bringing water to a mine or mill. 

Flux. A salt or other mineral added in smelting to assist fusion 
by forming more fusible compounds. 

Foliated. Arranged in leaf-like lamina (such as mica schist). 

Foot-wall. The wall under the vein. 

Forfeiture. The loss of possessory title to a mine by failure to 
comply with the laws prescribing the quantity of assessment work, or 
by actual abandonment. 

Formation. The series of rocks belonging to an age, period or 
epoch, as the Silurian formation. 

Fossil. Term applied to express the animal or vegetable remains 
found in rocks. 

Founder shaft. The first shaft sunk. 

Free. Native, uncombined with other substances, as free gold or 

Free-milling. Applied to ores which contain free gold or silver, 
and can be reduced by crushing and amalgamation, without roasting 
or other chemical treatment. 

324 prospector's field-book and guide. 

Fritting. The formation of a slag by heat with but incipient 

Fuller's earth. An unctuous clay, usually of a greenish-gray tint, 
compact yet friable. Used by fullers to absorb moisture. 

Fuse. In blasting the fire is conveyed to the blasting agent by 
means of a prepared tape or cord called the fuse. 

Gad. A steel wedge. 

Galiage. Eoyalty. 

Gallery. A level or drift. 

Gangue. The mineral associated with the ore in a vein. 

Gash. Applied to a vein wide above, narrow beljw, and termin- 
ating in depth within the formation it traverses. 

Geode. A cavity, studded around with crystals or mineral matter, 
or a rounded stone containing such cavity. 

Geysers. Intermittent boiling springs. 

Glacier. A body of ice which descends from the high to the low 

Glance. Literally, shining. Name applied to certain sulphides. 

Globule. A small substance of a spherical shape. 

Goaves. Old workings. 

Gopher or Gopher-drift. An irregular prospecting drift, following 
or seeking the ore without regard to maintenance of a regular grade 
or section. 

Gossan or Gozzan. Hydrated oxide of iron, usually found at the 
decomposed outcrop of a mineral vein. 

Gravel mine. In the United States, an accumulation of auriferous 

Grip. A small narrow cavity. 

Gh'it. A variety of sandstone of coarse texture. 

Gubbin. A kind of iron stone. 

Gulch. A ravine. 

Gullet. An opening in the strata. 

Hade. See Underlay. 

Hanging-side or Hanging-wall, or Hanger. The wall or side over 
the vein. 


Hard Head. A residual alloy containing much iron and arsenic, 
produced in the refining of tin. 

Heading. The vein above a drift; also an interior level or air- way- 
driven in the mine. 

Heading side. The under side of a lode. 

Heave. An apparent lateral displacement of a lode produced by 
a fault. 

Hog back. A sharp anticlinal, decreasing in height at both ends 
until it runs out; also a ridge produced by highly tilted strata. 

Homogeneous. Of the same structure throughout. 

Horse. A mass of country rock enclosed in an ore deposit. 

Hungry. A term applied to hard barren vein matter, such as 
white quartz. 

Hushing. The discovery of veins by the accumulation and sudden 
discharge of water, which washes away the surface soil and lays bare 
the rock. See Booming. 

Hydraulicking . Washing down a bank of earth or gravel by the 
use of pipes, conveying water under high pressure. 

Hydrous. Containing water in its composition. 

Igneous. Resulting from the action of fire, as, lavas and basalt 
are igneous rocks. 

Impregnation. An ore-deposit consisting of the country-rock im- 
pregnated with ore. 

Incline. A shaft not vertical; also & plane, not necessarily under 

Incrustation. A coating of matter. 

Indicator Vein. A vein which is not metalliferous itself, but, if 
followed, leads to ore deposits. 

In place. Of rock, occupying, relative to surrounding masses, the 
position that it had when formed. 

In situ. In place where formed. 

Intrusion. Forcing through. 

Irestone. Hard clay slate: hornstone; horn-blende. 

Iridescent. Showing rainbow colors. 


Jigging. Separating ores according to specific gravity with a sieve 
agitated up and down in water. The apparatus is called a jig or 

Jinny-road. A gravity plane underground. 

Jump. To take possession of a mining claim alleged to have been 
forfeited or abandoned; also, a dislocation of a vein. 

Keckle-meckle. The poorest kind of lead ore. 
Kibbal or kibble. An iron bucket for raising ore. 
Kicker. Ground left in first cutting a vein, for support of its 

King's yellow. Sulphide of arsenic. 
Knits or knots. Small particles of ore. 

Lagoon. A marsh, shallow pond or lake. 
Lamellar. In thin sheets. 
Lamina. A thin plate or scale. 

Lava. Eock formed by the consolidation of liquid matter which 
has flowed from a volcano. 
Leaching. See Lixiviation. 

Leads. The auriferous portions of alluvial deposits marking the 
former courses of streams. 

Leath. Applied to the soft part of a vein. 

Lenticular. Lens-like. 

Level. A horizontal passage or drift into or in a mine. 

Limp. An instrument for striking the refuse from the sieve 
washing ores. 

Litharge. Protoxide of lead. 

Lixiviation. The separation of a soluble from an insoluble 
material by means of washing with a solvent. 

Loadstone. An iron ore consisting of protoxide and peroxide 1 
iron; Magnetite. 

Locate. To establish a right to a mining claim. 

Lode. A regular vein carrying metal. 

Long Tom. A kind of gold-washing cradle. 


Magma. Paste or groundwork of igneous rocks. 
Mainway. A gangway or principal passage. 
Marl. Clay containing carbonate of lime. 
Mass-copper. Native copper occurring in large masses. 
Massicot. See Litharge. 

Matrix. The rock or earthy material containing a mineral or 
metallic ore; the gangue. 

Matt or Matte. A mass consisting chiefly of metallic sulphides 
got in the fusion of ores. 

Measures. Strata of coal, or the formation containing coal beds. 

Meat-earth. The vegetable mould. 

Metalliferous. Metal-bearing. 

Metamorphic. Changed in form and structure. 

Mine. In general, any excavation for minerals. More strictly, 
subterranean workings, as distinguished from quarries, placer and 
hydraulic mines, and surface or open works. 

Mineral. In miners' parlance, ore. 

Mineralized. Charged or impregnated with metalliferous mineral. 

Mineral-right. The ownership of the minerals under a given sur- 
face, with the right to enter thereon, mine and remove them. It 
may be separated from the surface ownership, but, if not so separated 
by distinct conveyance, the latter includes it. 

Mine-rent. The rent or royalty paid to the owner of a mineral 
right by the operator of the mine. 

Miners' inch. A local unit for the measurement of water supplied 
to hydraulic miners. It is the amount of water flowing under a cer- 
tain head through one square inch of the total section of a certain 
opening for a certain number of hours daily. 

Minium. Protosesquioxide of lead. 

Mock ore. A false kind of mineral. 

Monkey drift. A small prospecting drift. 

Monoclinal. Applied to any limited portion of the earth's crust 
throughout which the strata dip in the same direction. 

Mountain blue. . Blue copper ore. 

Muffle. A semi-cylindrical or long-arched oven, usually small 
and made of fire clay. 

328 prospector's field-book and guide. 

Mundic. Iron pyrites, called so in Cornwall. White mundic is 

Nacreous. Resembling mother-of-pearl. 

Native. Occurring in nature; not artificially formed; usually ap- 
plied to the metals. 

Nickeliferous or Niccoliferous. Containing nickel. 

Nittings. The refuse of good ore. 

Noble metals. The metals which have so little affinity for oxygen 
that their oxides are reduced by the mere application of heat with- 
out a reagent; in other words, the metals least liable to oxidation 
under ordinary conditions. The list includes gold, silver, mercury, 
and the platinum group. 

Nodule or Noddle. A small round mass. 

Nugget. A lump of native metal, especially of a precious metal. 

Nucleus. A body about which anything is collected. 

Open cut. A surface working, open to daylight. 

Ore. A natural mineral compound, of the elements of which one 
at least is a metal. 

Organic Compounds. Compounds containing carbon, generally 
derived from animals or plants. 

Outcrop. The portion of a vein or stratum emerging at the sur- 
face, or appearing immediately under the soil and surface debris. 

Output. The product of a mine. 

Oxidation. A chemical union with oxygen. 

Oxide. The combination of a metal with oxygen. 

Pack Walls. Walls built of loose material in mines to support the 

Panning. Washing earth or crushed rock in a pan, by agitation 
with water, to obtain the particles of greatest specific gravity it con- 
tains; chiefly practiced for gold, also for quicksilver, diamonds and 
other gems. 

Parting. The separation of two metals in an alloy, especially the 
separation of gold and silver by means of nitric or sulphuric acid. 

Pavement. The floor of a mine. 


Pay-streak. The zone in a vein which carries the profitable or 
pay ore. 

Peroxide. An oxide containing more oxygen than some other 
oxide of the same element. 

Peter or peter-out. To fail gradually in size or quality. 

Petrified. Changed to stone. 

Petrology. Study of rocks. 

Phosphates. Phosphoric acid combinations. 

Pinch. To contract in width. 

Pipe or pipe-vein. An ore-body of elongated form. 

Piping. Washing gold deposits by means of a hose. 

Placer. A deposit of valuable mineral, found in particles in allu- 
vium or diluvium, or beds of streams, etc. 

Plasma. A green variety of quartz. 

Plastic. Easily moulded. 

Plat. The map of a survey in horizontal projection. 

Plumbago. Graphite or black lead. 

Plumb Bob. A weight suspended by a string to determine vertical 

Plush Copper. A fibrous red copper ore. 

Pocket. A small body of ore. 

Porphyritic. Of the nature of porphyry. 

Potstone. Compact steatite. 

Precipitate. Term applied to solid matter which is separated from 
a solution by the addition of reagents or exposure to heat. 

Prill. A good sized piece of pure ore. 

Prisms. Solids whose bases are plane figures, and whose sides are 

Pryan. Ore in small pebbles mixed with clay. 

Pudding -Stone. A conglomerate in which the pebbles are rounded. 

Pulp-assay. The assay of samples taken from the pulp, i. e., pul- 
verized ore and water, after or during crushing. 

Putty powder. Crude oxide of tin. 

Quarry. An open or day working. 

330 prospector's field-book and guide. 

Quartz. Crystalline silica ; also, any hard gold or silver ore, as 
distinguished from gravel or earth, hence quart-mining as dis- 
tinguished from hydraulic mining, etc. 

Quartzose. Containing quartz as a principal ingredient. 

Quicksand. Sand which is, or becomes, upon the access of water, 

"quick," i. e., shifting, easily movable or semi-liquid. 

Race. A small thread of spar or ore. 

Radiating. Diverging from a centre. 

Mange. A mineral-bearing belt of rocks. 

Ravine. A deep narrow valley. 

Reduce. To deprive of oxygen; also, in general, to treat metal- 
lurgically for the production of metal. 

Refractory. Kesisting the action of heat and chemical agents. 

Reniform. Kidney-like. 

Reticulated Veins. Veins traversing rocks in all directions. 

Reverse Faults. Faults due to thrust; the hanging-wall side of the 
fault being forced upwards on the foot-wall. 

Rider. See Horse. 

Riffle. A groove or interstice, or a cleat or block, so placed as 
to produce the same effect, in the bottom of a sluice, to catch free 

Rim-rock. The bed-rock rising to form the boundary of a placer 
or gravel deposit. 

Rise. That portion of a bed or coal-seam which lies above a level 
is said to be " to the rise." 

Roasting. Calcination, usually with oxidation. 

Rocker. A short trough in which auriferous sands are agitated 
by oscillation in water, to collect their gold. 

Rolley-way. A gangway. 

Roof. The strata immediately above a coal seam. 

Rosette copper. Disks of copper, red from the presence of sub- 
oxide, formed by cooling the surface of melted copper through 
sprinkling with water. 

Royalty. The dues of a lessor or landlord of a mine, or of the 
owner of a patented invention. 


Rusty gold. Free gold which does not easily amalgamate, the 
particles being coated, as is supposed,, with oxide of iron. 

Saccharoid. Like lump-sugar. 

Saddle. An anticlinal in a bed or flat vein. 

Sal ammoniac. Chloride of ammonium. 

Saline. A salt-spring or well; salt works. 

Sampling. Mixing ores so that a portion taken from the mixture 
may fairly represent the whole body. 

Schist. Crystalline rock. 

Schorl. Black tourmaline. 

Seam. A stratum or bed of coal or other mineral. . 

Sectile. Easily cut. 

Sediment. A deposit formed by water. 

Segregate. To separate the undivided joint ownership of a mining 
claim into smaller individual ''segregated" claims. 

Segregation. A mineral deposit formed by concentration from the 
adjacent rock. 

Salvage or Selfedge. A layer of clay or decomposed rock along a 

Shaft. A pit sunk from the surface. 

Shake. A cavern, usually in limestone; also a crack in a block of 

Shale. Consolidated clay. 

Shift. The time for a miner's work in one day; also the gang of 
men working for that period, as the day-shift, the night-shift. 

Shingle. Clean gravel. 

Side-basset. A transverse direction to the line of dip in strata. 

Silicates. Compounds of silica or silicic acid with a base. 

Siliceous. Consisting of or containing silex or quartz. 

Sinter. A deposit from hot springs. 

Slag. The vitreous mass separated from the fused metals in smelt- 
ing ores. 

Slate. Indurated clays, sometimes metamorphosed. 
Slickensides. Polished and sometimes striated surfaces on the walls 
of a vein, or on interior joints of the vein-material or of rock masses. 

332 prospector's field-book and guide. 

Slide. A fault or cross course. 

Slime ore. Finely crushed ore mixed with water to the consistence 
of mud or slime. 

Sline. Natural transverse cleavage of rock. 

Slip. A vertical dislocation of rocks. 

Slope. An inclined opening to a mine. 

Sluicing. Washing auriferous earth through long boxes (sluices). 

Slums. The most finely crushed ores. 

Spall or Spawl. To break ore. Pieces of ore thus broken are 
called spalls. 

Speiss or speise. Impure metallic arsenides, principally of iron, 
produced in copper and lead smelting. Cobalt and nickel are found 
concentrated in the speiss obtained from ores containing these metals. 

Spoon. An instrument made of an ox or buffalo horn, in which 
earth or pulp may be delicately tested by washing to detect gold, 
amalgam, etc. 

Spur. A branch leaving a vein, but not returning to it. 

Stalactites. Icicle-like incrustations hanging down from the roof 
of caves. 

Stalagmites. Similar to stalactites, but formed on the floor of 
the caves by the deposition of solid matter held in solution by drop- 
ping water. 

Stannary. A tin mine, or tin works. 

Step-vein. A vein alternately cutting through the strata of country- 
rock and running parallel with them. 

Stockwork. An ore deposit of such a form that it is worked in 
floors or stories. 

Stope. To remove the ore. 

Stratum. A bed or layer. 

Streak. The powder of a mineral, or the mark which the latter 
makes when rubbed upon a harder substance. 

Striated. Marked with parallel grooves or strice. 

Strike. The direction of a horizontal line drawn in the middle 
plane of a vein or stratum not horizontal. 

String. A small vein. 

Strip. To remove from a quarry, or open working, the overlying 
earth and disintegrated or barren surface rock. 


Stull. A platform laid on timbers, braced across a working from 
side to side, to support workmen or to carry ore or waste. 

Sturt. A tribute-hdiYg&m which turns out profitable for the miner. 

Sublimation. The volatilization and condensation of a solid sub- 
stance without fusion. 

Submetallic. Of imperfect metallic lustre. 

Subsidence. The sinking down of. 

Subtransparent. Of imperfect transparency. 

Sulphate. A salt containing sulphuric acid. 

Sulphide. A combination of metal with sulphur. 

Sulphurets. In miners' phrase, the undecomposed metallic ores, 
usually sulphides. Chiefly applied to auriferous pyrites. 

Synclinal. The axis of a depression of the strata; also the depres- 
sion itself. Opposed to anticlinal, which is the axis of an elevation. 

Tailings. The lighter and sandy portions of the ore on a buddle 
or in a sluice. 

Tail-race. The channels in which tailings, suspended in water, 
are conducted away. 

Thermal. Hot, e. g., thermal springs. 

Throw. A dislocation or fault of a vein or stratum, which has 
been thrown up or down by the movement. 

Tinstone. Ore containing small grains of oxide of tin. 

Toadstone. A kind of trap-rock. 

Toughening. Refining, as of copper or gold. 

Translucent. Allowing light to pass through, yet not transparent. 

Trap. In miners' parlance, any dark igneous, or apparently 
igneous, or volcanic rock. 

Trend. The course of a vein. 

Tribute. A portion of ore given to the miner for his labor. 

Trogue. A wooden trough, forming a drain. 

Trow. A wooden channel for air or water. 

Tuff or Tufa. A soft sandstone or calcareous deposit. 

Tunnel. A nearly horizontal underground passage, open at both 
ends to day. See Adit. 

Turn. A pit sunk in a Drift. 

334 prospector's fie,ld-book and guide. 

Underlay or Underlie. The departure of a vein or stratum from 
the vertical, usually measured in horizontal feet per fathom of 
inclined depth. 

Unstratified. Not arranged in strata. 
Upcast. The lifting of a coal seam by a dike. 

Vanning. Washing "tin-stuff" by means of a shovel. 

Vein. See Lode. The term vein is also sometimes applied to 
small threads, or subordinate features of a larger deposit. 

Vein stuff. Ore associated with gangue. 

Vermilion. Mercury sulphide. 

Vitreous. Glassy. 

Volatile. Capable of easily passing off as vapor. 

Vug, Vugg or Vugh. A cavity in the rock, usually lined with a 
crystalline incrustation. See Geode. 

Walls. The boundaries of a lode, the upper one being the 
'" hanging," the lower the " foot wall." 

Wash Dirt. Auriferous gravel, sand, clay, etc. 

Wastrel. A tract of waste land, or any waste material. 

Weathering. Changing under the effect of continued exposure to 
atmospheric agencies. 

Whim or Whimsey. A machine for hoisting by means of a verti- 
cal drum, revolved by horse or steam power. 

White-damp. A poisonous gas sometimes encountered in coal 

Wild lead. Zinc blende. 

Win. To extract ore or coal. 

Wing Dams. Dams built from the side of a river with the object 
of deflecting it from its course. 

Winze. An interior shaft, usually connecting two levels. 

Working home. Working toward the main shaft in extracting ore. 

Working out. Working away from the main shaft in extracting 

Zinc-scum. The zinc-silver alloy skimmed from the surface of the 
bath in the process of desilverization of lead by zinc. 
Zinc-white. Oxide of zinc. 


ACID, nitric, preparation of, 
Acidic rocks, 185 
Acids, 12 
Actinolite, 8 
Adularia, 239 

Africa, diamonds in, 271, 272 
Agate, 3, 284 
Alabaster, 243 

Alaska, burning and drifting in, 
118, 119 

gold in, 136-138 
Albite, 3 
Alloys, estimation of gold in, 

Alluvial claims, estimating the 

value of. 41, 42 
Almaden, Spain, quicksilver de- 
posits at, 204 
Almandine, 281 
Almandine ruby, 277 
Alum, 231 

Alumina, detection of, 80 
Aluminite, 221 

Aluminous schists or shales, 231 
Aluminium, 221-226 
Aluminium, antimony, manga- 
nese, 221-230 

minerals as sources of, 221 
Amalgamating assay, 120-122 
Amalgams, 202 

native, 203 
Amazon stone, 239, 240 
Amethyst, 3, 286 

oriental, 225, 277 
Amphibole, 7, 8 
Amydolite, 27 

Analysis of ores for nickel and 
cobalt, 209-216 

qualitative, of ores, 82-94 

wet method of, 79-94 


Analyses of ores, 79 
Anglesite, 177 
Anorthite, 5 
Anthracite, 238 
Antimonite, 226, 227, 228 
Antimony, 226-228 

assay of, 101, 102 

detection of, 80 

glance, 226, 227, 228 
Apatite, 231-233 
Aqueous rocks, 29-31 
Areas, to measure, 72-75 
Argentite, 149, 150 
Arsenic, 233, 234 

indication of, 79 
Arsenical pv rites, 196 
Asbestus, 8," 11, 234 
Asbolite, 219 
Asphalt, native, 264, 265 
Assay, amalgamating, 120-122 

definition of, 49, 50 

furnace, 94, 95 

furnace, portable, for field 
testing, 95, 96 

of antimony, 101, 102 

of bismuth, 102 

of cobalt, 102 

of copper, 170-173 

of copper ore, 101 

of galena, 101 

of gold and silver ores, 98- 

of gold by the touchstone, 
304, 305 

of lead ore, 101 

of manganese, 102 

of mercury, 101 

of nickel, 102 

of tin ore, 101, 181, 182 

of zinc, 102 
Asterias, 225 



Augite, 9, 10 
Auriferous lodes, 36, 37 
Australian gold, 104, 105 
Aventurine, 239 
Avoirdupois weight, 297 
Azoic rock, 24 
Azurite, 165 

BANCA, discovery of tin in, 183 
Barium sulphate, 234, 235 
Barytes, 234. 235 
Basalt, 27, 28 
Basanite, 3 
Bases, 12 
Bassets, 34 
Batea, 108 

Bauxite, 221, 222, 223 
Beds and layers, 34 
Bell metal, 184 
Beryl, 270 

Billiton, discovery of tin in, 183 
Biotite, 6, 7, 31, 130, 245 
Bismuth, 205, 206 

assay of, 102 

gold, 105 
Bitumen, 264, 265 

elastic, 263 
Bituminous coal, 238 
Black band ore, 194, 195 

diamond 274 

gold, 105 

jack, 189, 190 

lead, 240-242 

mica, 245 

oxide of copper, 164, 165 

tellurium, 141, 142 
Blende, 189, 190 
Bloodstone, 285 
Blowing, 110 
Blow-pipe and its uses, 46-58 

experiments, 53-58 

making a, from a glass tube, 
52, 53 

manipulation of the, 48, 49 

practice, chief requirements 
for, 47 
reagents for, 47, 48 

principal means of testing 
minerals before the, 53 
Blue carbonate of copper, 165 

ground, 272 

Blueite, 209 

Bog iron, occurrence of, 44 

Bole, 237 

Borax, 47, 48, 235, 236 

blow-pipe test with, 53-55 
Boring. 308 

bars, 308 
Borneo, diamonds in, 270, 271 
Bornite, 165 
Brazil, diamonds in, 271 
British weights and measures, 

basis of, 295, 296 
Brittle silver ore, 151 
Bromic silver, 152 
Bromyrite, 152 
Brown coal, 238 

hematite, 193, 194 

iron ore, 193, 194 
Burning and drifting, 118, 119 

pADMIUM, 220 
\J Calcite, hexagonal crystal, 64 
Calamine, 188, 189 
California, gold-bearing beds in, 
Gulch, Colorado, section of 
strata in, showing portion 
of carbonate of lead de- 
posits, 176 
quicksilver-bearing belt of, 
204, 205 
Californian gold, 104, 105 
Cannel coal, 238 
Carbonate of lead, 176, 177 

deposits, section 
of, 176 _ 
soda, blow-pipe test 
with, 55, 56 
preparation of, 
Carbonates, detection of, 81 
Carbuncle, 281 
Carnelian, 285 
Casing. 34 
Cassiterite, 182, 183 

occurrence of, in the United 
States, 184, 185 
Cat's eye, 287 
Cement, 117 
Cerargyrite, 150, 151 
Cerussite, 176, 177 



Chalcedony, 3, 285 
Chalcocite, 162 

Chalcopyrite, 16, 163, 164, 208 
Chemical elements, rule for find- 
ing the propor- 
tional parts by 
weight of, 311 
alents and specific 
gravities, table of, 
309, 310 
substances, common names 
of, 311, 312 
China clay, 236, 237 
Chlorite, 10, 11 
Chlorospinel, 277 
Chromate of lead, 177, 178 
Chromic iron ore, 195 
Chromite, 195 
Chrysocolla. 164 
Chrysoprase, 285 
Chrysotile, 11 
Cinnabar, 203 
Cinnamon stone, 281 
Citron quartz, 286 
Clays, 236. 237 
Cleavage, 17 
Coal, 237, 238 
Cobalt, 217-220 

and nickel ores, analysis of, 
separation of, 215, 216 
assay of, 102 
bloom, 219 
detection of, 80 
geologv of, 219, 220 
wad, 219 
Cobaltite, 218 
Colors, accidental, effect of, 14 

of minerals, 13-15 
Compass, use of, in searching for 

ore, 200, 201 
Comstock Lode, extent of, 155 

section of, 154, 156 
Contact deposits, 35 
Copper, 160-173 

assay of, 170-173 
detection of, 81 
examining a mineral for. 169 
exploring a new country for, 
168, 169 

Copper, geology of, 166-170 

glance, 162 

in an ore, to obtain the per 
cent, of, 170-173 

native, properties of, 160 
testing of, 160, 161 

natural combinations of, 161 

nickel, 206, 207 

ore, assay of, 101 

ores, weight of, 169 

pyrites, 163, 164 

separation of, 210 

world's supply of, 166 
Corundum, 221, 224-226 

and emery, 224-226 
Country, definition of, 32 
Cradle, 111, 112 
Creeks, wash of, as a guide in 

prospecting, 38, 39 
Crocoite, 177, 178 
Crucible, melting ore in a, 99 
Crucibles, 94 
Cryolite, 221, 223, 224 
Crystalline forms, system of, 59 
Crystallography, 59-69 

systems, illustrations of, 65, 
Cube, the, 60, 61 
Cupel, 94 
Cupellation, 98, 99 
Cuprite, 161, 162 

DARTON'S gold test, 122, 123 
Delfs, 34 
Deposit of economic value, first 

indications of a, 31, 32 
Deposits, irregular, 35 

metalliferous localities of, 31, 

superficial, looking for indi- 
cations of, 43, 44 
surface, 35 
Diamond, 270-276 
black, 274 
colors of, 273, 274 
drill, 308, 309 
natural surface of, 273 
power of refraction of, 274 
specific gravity of, 274 
value of, 275 
Diaspore, 221 



Dichroiscope, use of the, 268-270 

Dip of a lode, 32 

Dodecahedron, 61 

Dolerite, 27 

Dolly Hide Mine, Md. , section 

of copper bed at, 167 
Dolomite, 238 
Dry assay of ores, 94-102 
Ductility, 20 

EAGLE Vein, Lake Superior, 
section of, 168 
Earth's crust, movements of, 24, 

Earthy cobalt, 219 
Elastic bitumen. 263 
Elasticity and flexibility, 19 
Elaterite, 263 
Electricity, prospecting by means 

of, 293-295 
Emerald, 270 

nickel, 207 
Emery and corundum, 224-226 
Emma Mine, 158 
English length, 296 
Epidote, 282 
Erubiscite, 165 
Erythrite, 218, 219 
Eureka Mines, Nevada, 157 
Eye agates, 284 

FALSE topaz, 286 
Feldspar, 3-5, 239, 240 

Fire lute, 102 

Fire opal, 282 

Flames of a sperm candle, 49, 50 
il lustration 
and practice 
showing the 
c h a r a c ter- 
istic power of 
either, 51, 52 

Flexibility and elasticity, 19 

Flint. 3, 240 

Float gold, 118 

Florentine, 276 

Fluorite, 240 

Fluorspar, 240 

Foleyrite, 208 

Foliated tellurium, 141, 142 

Formations, definition of, 33, 34 

Fracture, 17 
Franklinite, 192, 193 
French measures, 301 

weight, 301 
Fuller's earth, 237 
Fuming* nitric acid, 132 

GALENA, assay of, 101 
district of Wisconsin, Il- 
linois and Iowa, order 
of strata in the, 175 
geology and form of lodes 

of, 175 
limestones, 178, 179 
properties of, 174 
test for silver in, 174, 175 
Gap Mine, Lancaster Co., Pa., 

nickel in, 207, 217 
Garnet, 68, 69, 280, 281 
Garnierite, 217 

Gems and precious stones, 266- 
examination of, with the 

dichroiscope, 268-270 
prospecting for, 266, 267 
table of characteristics of, 
Gemstones known to occur in the 
United States, list of, 288, 
289 _ 
occurring only in the United 

States, list of, 289 
species and varieties of, not 
yet identified in any form, 
in the United States, 289 
Geology, mineralogy, mining, 
prospecting, etc , glossary 
of terms used in connec- 
tion with, 315-334 
of bismuth, 206 
of cobalt, 219, 220 
of copper, 166-170 
of gold, 125-130 
of iron, 196-198 
of lead, 178-181 
of manganese. 280 
of silver ores, 152-159 
of zinc, 190, 191 
practical, 25-31 
Gibbsite. 221 
Girdles, 34 



Glance coal, 238 
Glass tubes, tests in, 57, 58 
Glossary of terms used in connec- 
tion with prospecting, raining, 
mineralogy, geology, etc., 315- 
Gneiss, 28 
Gold. 103-140 

amalgam, 105, 124 
amalgamating assav of, 120- 

assay of, by the touchstone, 

304, 305 
association of, with iron, 124 
chief supplies of, 104 
color of, 16, 106, 107 
crystallization of, 105 
crystals, 105 
distribution of, 103, 104 
dust, 105 

free, in drifts and sands, 128 
in Alaska, 136-138 
in alloys, estimation of, 305- 

in combination, 130-136 
in metallic sulphides, sepa- 
ration of, 131-136 
in pyrites, detection of, 105 
irregular deposits of, 127.128 
native, constitution of, 104 
determination of, 79 
occurrence of, 125 
nuggets, 105, 106 
occurrence of, 104 

in different 
forms, 123- 
in granitic reg- 
ions, 126, 127 
in quartz, 125 
of the Yukon district, de- 
rivation of, 137 
ores, assay of, 98-100 
original position of, 125, 126 
panning. 108-111 
placer, 39-41, 124 
properties of, 107, 108 
quartz, assaying of, 100 
rule for ascertaining the 
amount of, in a lump of 
auriferous quartz, 139, 140 | 

Gold, section showing the two 
conditions under which 
usually found in rock and 
drift, 127 ®^ 

standard value of, in differ- 
ent countries, 307 
test, Darton's, 122, 123 
Grand Duke of Tuscany, 276 
Granite, 29-31 
Granitic regions, gold in, 126. 

Graphic granite. 30 

tellurium, 142, 143 
Graphite, 240-242 

test for the purity of, 242 
Gray copper ore, 162, 163 
Green carbonate of copper, 165 

jade, 8 
Greenockite, 220 
Greenstone, 27 
Greisen, 186 
Guadalcazarite. 203 
Gypsum, 242, 243 

Hard bars, 44 
Hardness, 18, 19 

scale of, 18, 19 
Harlequin opal, 282, 283 
Heavy spar, 234, 235 
Heights, inaccessible, to measure, 

Heliotrope. 285 
Hessian crucibles, 94 
Hessite, 142 

Hexagonal system, 62-64 
Horizons, 24 
Hornblende, 7, 8 
Horn silver, 150, 151 
Hornstone, 3, 240 
Horse, definition of, 34 
Hydraulic mining. 115-117 
Hydrogen, apparatus for evolv- 
ing, 213, 214 
sulphide, apparatus for, 85- 
Hyposyenite, 130 

IDRTA, Austria, cinnabar at, 
Igneous rocks, 27, 28, 129 



India, diamonds in, 270 
Indicative plants, 42, 43 
Infusorial earth, 243 
Instruction, preparatory, 1-45 
Iridium, 147 
Iron, 191-201 
alum, 231 

association of gold with, 124 
geology of, 196-198 
indication of, 42 
meteoric. 68 
mode of obtaining the amount 

of, in an ore, 96 
ores, geologic regions of, 
197, 198 
of Lake Superior, geo- 
logical horizons 
around the, 197 
pyrites, 16, 131-134, 195, 

separation of, 211 
sulphides, gold in, 130 
use of magnetic needle in 
prospecting for, 1 98-201 
Ironstone '• blow out," 127 
Isometric system, 59-61 
ltacolumite, 125 

Jack's tin, 209 
Jade, 8 

Jamesonite, 178 
Jasper, 285 
Jasper opal, 283 
Jet, 238 
Jumpers, 308 

KAOLIN, 236, 237 
Kermesite, 226 

Kimberley mine, diamond-bear- 
ing ground of, 272 

Klondike district. Alaska, 136- 

Koh-i-noor, 276 

Kunz, George F. , list of gem- 
stones, known to occur in the 
United States, compiled by, 

Lake George diamonds, 286 

Lake Superior copper region y 

section of strata in, 


iron ores, geological 

horizons around the, 

• 197 

Lancaster Co., Penna. , nickel in, 

Lapis lazuli, 67 
Lazulite, 66 
Lead, 174-181 

and tin, 174-187 
-antimony ores. 178 
carbonate of, 176. 177 
chief sources of, in the United 

States, 180. 181 
chromate of, 177, 178 
deposit in a fissure of lime- 
stone, section of. 181 
geology of, 178-181 
indication of, 42 
lode in micaceous slate in 
mine near Middletown, 
Conn., 175 
mine, circulation of water in 

a, 180 
ochre, 178 
ore, assay of. 101 
phosphate of, 177 
separation of, 209, 210 
sulphate of, 177 
Ledge, 32 
Length, English, 296 

particular measures of, 296 
Lepidolite, 6, 7 
Lepidomelane, 7 
Licks, 247 
Lignite, 238 _ 
Lime, detection of, 80 
Limestone, indication of, 43 

lithographic, 243, 244 
Limonite, 193, 194 
Line, ii.accessible, to measure, 

Linnseite, 219 
Lithia mica, 7 

Lithographic limestone, 243, 244 
Loadstone, 191, 192 
Locating, notice of, 313, 314 
Lode, examination of a, 44 
prospecting, 119 



Lodes, 32-34 

auriferous, 36, 37 
Long torn, 112-114 
Lustre, 21 
Lydian stone, 3 

MAGNESIA alum, 231 
detection of, 80 
Magnetic iron ore, 191, 192 

needle, use of, in prospecting 
for iron, 198-201 
Magnetite, 191, 192 

occurrence of, 44 
Malachite, 165 
Malleability, 20 
Manganese, 228-230 
assay of, 102 
carbonate, 229, 230 
detection of, 80 
geology of, 230 
localities of, 230 
occurrence of, 44 
Massicot, 178 
Measures, 34 

and weights, 295-304 
Meerschaum, 244 
Mercury, 202-205 

and silver, native amalgams 

of, 203 
assay of, 101 
bismuth, nickel, cobalt and 

cadmium, 202-220 
detection of, 81 
Metacinnabarite, 203 
Metallic sulphides, separation of 

gold in, 131-136 
Metalliferous deposits, localities 
of, 31, 32 
veins, association of ore in, 
Metals, native, 16 

specific gravitv of. 302, 303 
Metamorphic rocks, 28, 29, 129 
Meteoric iron, 68 
Mexico, emerald mine in, 279 
Mica schist, *8, 29 
Micas, 5 7, 244, 245 
Michigan, salt in, 247 
Middletown, Conn., lead lode in 
micaceous slate in mine near, 

Milk opal, 283 
Millerite, 207 
Mills, power of, 307, 308 
Mineral coal, 237, 238 
definition of a, 2 
effect of intermixture of 

coloring matter on a, 14 
examining a, for copper, 169 
test of the hardness of a, 19 
tin-bearing, testing a, 181 
Mineralogy, mining, geology, 
prospecting, etc., glossary 
of terms used in connec- 
tion with, 315-334 
special, 103-292 
technical, 1-25 
Minerals associated with tin, 186 
basic, 12 
calculations of elements in, 

11, 12 
chemical tests for, 46 
cleavage of, 17 
colors of, 13-15 
composition of, indicated by 

their forms, 59 
constituting rocks, 3 
ductility of, 20 
flexibility and elasticity of, 

fracture of, 17 
lustre of, 20 
malleability of, 20 
naturally colorless, 13 
of common occurrence, spe- 
cific gravity of, 302, 303 
phosphorescence in, 15 
principal means of testing, 

before the blow-pipe, 53 
properties of, 2 
smell of, 19, 20 
specific gravity of, 22 
streak of. 17 
taste of, 20 

tests of, in glass tubes, 57, 58 
various useful, 231-251 
weight and form of. 22, 23 
Miners' superstitions, 37 , 

Mines. 34 

Mining, hydraulic, 115-117 
Mining, mineralogy, geology, 
prospecting, etc , glossary of 



terms used in connection with, 
Mispickel, 147, 196 
Molybdenite, 245, 246 
Molybdenum, 245, 246 
Monoclinic system, 65 
Moonstone, 239 
Moss agate, 284 
Mountain cork, 8 

leather, 8 

wood, 8 
Mud volcanoes, 256 
Muffle, 94 
Muscovite, 5, 6, 31, 245 

NAGYAGLTE, 141, 142 
Native amalgams, 203 
arsenic, 233 
asphalt, 264, 265 
Nephrite, 8 

Nevada, rock salt in, 248 
New Caledonia, nickel in, 217 
Nickel, 206-217 

and cobalt ores, analysis of, 
separation of, 215, 
arsenide, 206, 207 
assay of, 102 
detection of. 80 
Niccolite, 206, 207 
Nitre, 246 

Nitric acid, preparation of, 131, 

Octahedron, 61 
Oligoclaee, 3 
Onyx, 287 
Opal, 3, 282, 283 
Ore, association of, in metallifer- 
ous veins, 45 
copper, assay of, 101 
lead, assay of, 101 
mode of obtaining the 
amount of iron in an, 69 
* melting of, in a crucible, 99 
pulverization of, 97 
tin, assay of, 101 
use of the compass in search- 
ing for, 200, 201 

Ores, analyses of, 79-102 

dry assav of. 94-102 

gold, assay of, 98-100 

nickel and cobalt, analysis 
of, 209-216 

preliminary examination of, 

qualitative analysis of, 82- 

silver, assay of, 98-100 

specific gravity of, 302. 303 
Oriental amethyst, 225, 277 

jade, 8 

ruby, 225 

topaz, 225 
Orlof, 276 
Orpiment, 234 
Orthoclase, 3, 239 
Orthorhombic system, 64, 65 
Osmium, 147 
Oxidizing flame, 49 
Ozocerite, 261, 262 

Panning out, 108-111 
Placer deposits, gold in, 39, 41 
most important, 137 
diggings, character of, 40, 41 
gold, 39-41, 124 
Placers, 39-41 
Plants, indicative, 42, 43 
Plaster of Paris, 243 
Plastic clay, 237 
Platinum, 143-147 

chemical test for, 145, 146 
Peacock ore, 164 
Peat, 265 
Pelton wheel, rule applicable to, 

307, 308 
Petite Anse Island, rock salt de- 
posit of, 247, 248 
Petroleum, 252 261 

bed-like occurrence of, 257 
indications of, 253 
occurrence of, 252 
ozocerite, asphalt, peat, 252- 

prospecting for, 252-261 
quality of, 261 
vein-like occurrence of, 259, 



Petroleum, water test for, 254 

Petzite, 142 

Phenacite, 279, 280 

Phlogopite, 6 

Phosphate, indication of, 43 

of lead, 177 

of lime, 231-233 
Phosphorescence, 15 
Pilot Knob, Mo. , section of, 198 
Pilot-stones, 39 
Pitt, 276 
Pleonast, 277 
Plumbago, 240-242 
Pockets, 35 
Polaric, 191, 192 
Polychroism, 15 
Porcelain clay, 236, 237 
Porphyritic granite, 30 
Potash alum, 231 
Pot holes, 44 
Pottery clay, 237 
Power for mills, 307, 308 
Precious stones and gems, 266- 

Preparatory instructions, 1-45 
Prism compass, use of, 77, 78 

hexagonal, 63 
Prospecting by means of elec- 
tricity, 293-295 

color of the rocks as a guide 
in, 37, 38 

for gems, 266, 267 

for iron, use of the magnetic 
needle in, 198-201 

for petroleum, 252-261 

locality for starting, 36 

mining, mineralogy .geology, 
etc. , glossary of terms used 
in connection with, 315- 

of lodes, 119 

wash of rivers and creeks as 
a guide in, 38, 39 
Prospectors' pointers, 313, 314 
Psilomelane, 229 
Pulverization for the dry method, 

97 y 

Pyrargyrite, 151, 152 
Pyrite, 16 
Pyrites, arsenical, 196 

detection of gold in, 105 

Pyrites, estimating the available 
sulphur in, 250 
iron, 195, 196 
Pyrolusite, 228, 229 
Pyromorphite, 177 
Pyropissite. 263 
Pyroxene, 9, 10 
Pyrrhotite, 208 

AUALITATIVE analysis of 
Y ores, 82-94 
Quartz, 3 

auriferous, rule for ascer- 
taining the amount of gold 
in a lump of, 139, 140 

crystals, 63 

limpid, 3 

occurrence of gold in, 125 

rocks, 126 
Quicksilver, 202-205 

Ked copper ore, 161, 162 
hematite, 193 
oxide of zinc, 189 
silver ore, 151, 152 
Reducing flame, 49 
Reef, 32 
Regent, 276 
Resin opal, 283 
Retinite, 263 
Retort, making a, 121 
Rhodocrosite, 229, 230 
Rhodium gold, 105 
Riffle box, 113 
Right-hand theory, 37 
Rivers, wash of, as a guide in 

prospecting, 38, 39 
Roasting, definition of, 51 
JRock and drift, section showing 
the two conditions under 
which gold is usually 
found in, 127 
azoic, 24 
boring of, 308 
crystal, 286 
igneous, 23 
salt, 246-248 
Rocker, 111, 112 
Rocks, acidic, 185 
aqueous, 29-31 



Rocks, classification of, 26 

color of, as a guide to the 

prospector, 37, 38 
definition of, 2 
igneous, 27, 28, 1*29 
metamorphic, 28, 29, 129 
principal constituents of, 3 
specific gravity of, 302, 303 
volcanic, 27 

Rose quartz, 286 

Rubicelle, 277 

Ruby, 277 

copper, 161, 162 
crystallization of, 68, 69 
oriental, 225 
silver, 151, 152 

Ruby Hill mines, 158 

SALSES, 256 
Salt deposits, 247 
licks, 247 

source of the bulk of, in 
the United States, 248 
Saltpetre, 246 
Salts, 12 
Sandstone, 29 

examination of, 81, 82 
oil-bearing, 254 
outcrops of oil in, 257, 258 
Sapphire. 225. 276, 277 

crystallization of, 68, 69 
Sard, 285 
Sardonyx, 287 
Satin spar, 243 
Scale of hardness, 18, 19 
Scales, 96, 97 

Scranton, W. H. , on indications 
from the magnetic needle in 
searching for ore, 199-201 
Scorifiers, 94 
Selenite, 243 

Selenium, indication of, 79 
Senarmontite, 226 
Sepiolite, 244 
Serpentine, 11 
Siberian gold, 104, 105 
Siderite, 194 
Silicate of copper, 164 
Silicates, 13 
Sills, 34 
Silver, 147-159 

Silver and gold, native am alga mg 
of, 203 
and- mercury, native amal- 
gams of, 203 
blow-pipe test of, 147 
chemical test for, 148 
glance, 149, 150 
indication of, 43, 79 
in galena, test for, 174, 175 
native, appearance of, 148 

determination of, 79 
ores, assay of, 98-100 
geology of, 152-159 
valuing of, 152 
principal source of, 149 
sulphide, 151 
Slate, 249 
Sluices, 114, 115 
Smaltite, 206, 218 
Smell of minerals, 19, 20 
Smithsonite, 188 
Smoky quartz, 286 
Soapstone, 250, 251 
Soda alum, 231 

carbonate of, blow-pipe teste 

with. 55, 56 

preparation of, 


Solid measure, 297 

South Africa, diamonds in, 271, 

Sparta, N. J., zinc mine, section 

of strata near, 190 
Spathic iron ore, 194 
Specific gravity, 20 

how to find, 299, 300 
of metals, ores, rocks, 

etc., 302. 303 
weight by, 297-299 
Specular ore, 193 
Sperm candle flame, colors of a, 

49, 50 
Sphalerite, 189, 190 
Stannous chloride, preparation 

of, 146, 147 
Steatite, 250, 251 
Stephanite, 151 
Sterling Iron Mines, N. Y.„ 

nickel at the, 207 
Stibnite, 226, 227, 228 
Stone coal, 238 



Strata, 34 

Streak, 17, 18 

Stream tin, 182 

Strike of a lode, 32 

Sudburv, Canada, sources of 

nickel in, 208 
Sulphate of lead, 177 
Sulphide of tin, 184 

of zinc, 189, 190 
Sulphur, 249, 250 

indication of, 79 
Sunstone, 239 
Surface deposits, 35 

measure, 296, 297 
Surveying, 70-78 
Swampy puddles, prospecting of, 

for oil, 255, 256 
Syenite granite, 30, 129 
Sylvanite, 142, 143 

TABLE of association of ore in 
metalliferous veins, 45 
of characteristics of gems, 

of chemical elements, their 
symbols, equivalents and 
specific gravities, 309, 310 
of common names of chemi- 
cal substances. 311, 312 
Tailings, 42 
Talc, 11, 250, 251 
Taste of minerals, 20 
Technical mineralogy, 1-25 
Tellurides, 143 
Tellurium, 141 

platinum, silver, 141-159 
Tetragonal svstem, 61, 62 
Tetrahedrite, 162, 163 
Ticonderoga, N. Y. , graphite 

beds at, 241 
Tin, 181-187 

-bearing mineral, testing a, 

detection of, 80 
granites, 186 

minerals associated with, 186 
ore, assay of, 101, 181, 182 
pyrites, 184 
stone, 182, 183 
Titanium, detection of, 81 
Toad-eye tin, 182 

Topaz, 278 

crystallization of, 67 

false, 286 

localities of, 67 
'"^oriental, 225 
Touchstone. 3 

assay of gold by the, 304, 305 
Tourmaline, 281, 282 
Trachyte, 27 
Traps, 27 
Tremolite, 8 
Triclinic system, 65 
Troy weight, 297 
Tungstate of soda, 187 
TurquoiS, 66, 283, 284 

localities of, 69 

United States, list of gem- 
stones known to 
occur in, 288 , 
localities of agate 
in, 284 
of beryl or 
emerald in, 
of diamonds in 

of epidote in, 

of garnet in, 

of lazulite in, 

of opal in, 283 

of sapphires in, 

of topaz in 67, 

of tourmaline 

in, 282 > 
of turquois in, 
283, 284 
Ural Mountains, structure of the, 

Uranium; detection of, 81 
Useful minerals, various, 231- 



VABIEGATED copper pyrites, 
Vitreous copper, 162 
Volcanic rocks, 27 

WAD, 228 
Wash, definition of, 38 
Water courses, prospecting of, 
for oil, 254, 255 
test for petroleum, 254 
weight of, 300 
Weighing, 96, 97 
Weight by specific gravity, 297- 

Weights and measures, 295-304 

special, 300 
Wet method of analysis, 79-94 
Whartonite, 208, 209 
White jade, 8 
mica, 245 
Willemite, 189 

Witherite, 235 
Wolframite, 187 
Wood opal, 283 
tin, 182 

YELLOW ground, 272 
quartz, 286 
Yukon district, derivation of the 
gold of, 137 

ZINC, 188-191 
and iron, 188-201 
assay of, 102 
carbonate, 188 
detection of, 80 
geology of, 190, 191 
indication of, 43 
mine, Sparta, N, J., section 
of strata near, 190 
Zincite. 189 
Zircon, 62 

Prospector's Collection Mo. 25. 

120 specimens, averaging 2% by 2 inches, arranged in pasteboard trays. All 
compactly held in small cabinet of finest workmanship. Interior of drawers 
are cherry, exterior handsomely finished in solid quartered oak, metal 
knobs. The collection is conveniently arranged for reference, each speci- 
men being labeled and numbered to correspond to the following list. Only 
typical specimens are selected, with a view to furnishing the most character- 
istic examples for study and comparison. 

Carriage Free to any A ddress in the World 
reached by Railroad or Steamship. 


Highest Jiwards and Medals for Collections of Minerals at 
Nine Great Expositions. 


(See next page.) 





An i?idisp ens able aid and guide to users of this book. 


1. Gold, native, in quartz. 

2. " " dust. 

3. " ore, pyritiferous, conglom. 

4. " " telluride. 


5. Native sih T er, in quartz. 

6. Argentite, glance. 

7. Stephanite. brittle silver. 

8. Cerargyrite, horn " 

9. Pyrargyrite, ruby " 


10. Copper, native. 

11. Cuprite, red oxide. 

12. Chalcocite, copper glance. 

13. Tetrahedrite, gray copper. 

14. Chalcopyrite. copper pyrites. 

15. Chrysocolla, silicate. 

16. Melacouite, black oxide. 

17. Malachite, green carbonate. 

18. Azurite, blue carbonate. 

19. Bornite, variegated pyrites. 


20. Galena, sulphide, cubic. 

21. " granular, argentiferous. 

22. Cerrusite, carbonate, gray. 

23. " " white cryst. 

24. Anglesite, sulphate. 

25. Pyromorphite, phosphate. 

26. Crocoite, chromate. 

27. Jamesonite. 


28. Cassiterite, tin oxide cryst'd 

29. '• " in greisen. 

30. " " massive. 

31. '• " " stream tin. 

32. Stannite, sulphide. 

33. Wolframite. 

34. Platinum, native grains. 


35. Smithsonite. carbonate. 

36. Calamine, silicate. 

37. Willemite. 

38. Zincite, oxide. 

39. Sphalerite, sulphide. 


40. Iron, meteoric. 

41. Magnetite, oxide, granular. 

42. " lodestone. 

43. Franklinite. 

44. Hematite cryst'd. 

45. " specular ore. 

46. Limonlte, brown ore. 

47. Siderite, spathic " 

48. Chromite, chromic ore. 

49. Pyrite, sulphide, cryst'd. 

50. " " massive. 

51. Arsenopyrite, mispickel. 


52. Cinnabar, mercury sulphide. 

53. Bismuth, native. 


54. Niccnlite, nickel arsenide. 

55. Zaratite, Emerald nickel. 

56. Millerite, nickel sulphide. 

57. Pyrrhotite, niccoliferous pyrite. 

58. (iarnierite, nickel silicate.* 

59. Cobaltite, sulph-arsenide. 

60. Asbolite, cobalt oxide. 

fll. Smaltite, Co. and Ni. arsenide. 

62. Bauxite, hydrate. 

63. Cryolite, fluoride. 

64. Corundum, gray cryst'd, oxide. 

65. " emery, black, " 

66. Stibnite, antimony sulphide. 


67. Wad, bog manganese. 

68. Pyrolusite, oxide. 

69. Psilomelane, " 

70. Rhodochrosite, carbonate. 


71. Apatite, hexagonal, cryst'd. 
72 " phosphate-rock. 

73. Arsenic, native. 

74. Realgar, red arsenic sulphide. 

75. Orpiment, yellow arsenic sul- 


76. Asbestns. 

77. Barite, orthorhombic, cryst'd. 

78. " massive, barium sulphate. 

79. Witherite, barium carbonate. 
i-0. Anthracite coal. 

81. Bituminous " 

82. Cannel coal. 

83. Dolomite, rhombohedral. 

84. " massive. 

85. Orthoclase, feldspar, monoclinic. 

86. " " cleavage. 

87. Microcline, Amazon-stone, tricl. 

88. Quartz var. rock crystal, hex. 

89. " •' flint. 

90. Fluorite, cubic. 

91. " massive. 

92. Calcite, cleavage rhomb. 

93. Graphite, plumbago. 

94. Gypsum, Selenite cryst., mouoc. 

95. * " Alabaster. 

96. ' ' granular. 

97. Infusorial earth. 

98. Lithographic limestone. 
y9. Meerschaum. 

100. Biotite, black mica. 

101. Muscovite, white mica. 

102. Molybdenite. 

103. Nitre. 

104. Halite, rock salt. 

105. Sulphur, native. 

106. Alunite, alum stone. 

107. Talc, soapstone. 

108. Petroleum. 

109. Ozocerite. 

110. Elaterite, elastic bitumen. 

111. Asphaltum. 



112. Diamond. 

113. Sapphire. 

114. Topaz. 

115. Emerald. 

116. Tourmaline. 

117. Garnet. 

118. Opal, noble. 

119. Turquois. 

120. Amethyst. 

This list includes all important minerals mentioned in the text, besides 
illustrating the Scale of Hardness and the six systems of Crystallization. 

in selecting specimens from our large stock, a collection is secured which 
represents, in a brief way, the varieties with which the prospector or miner 
is most likely to meet, and it has, therefore, a thoroughly practical value. 
Every specimen is accurately labeled with name and chemical composition, 
and numbered to correspond to above list. 

The following sizes are kept in stock ready for shipment : 

No. 23a. Prospector's Collection. $64.00. 120 specimens, averaging 
4%x3% inches. Handsome quartered oak glass wall-cases, $70.00 extra. 

No. 23. Prospector's Collection. $16.00. 120 specimens, averaging 
2%x2 inches. Handsome quartered oak case, three drawers, fitted with 
pasteboard trays, $10.00 extra. (See illustration.) 

The following items are selected from our " Collection Catalog " as of in- 
terest to the prospector. These are sold in the size 4%x3% inch specimens at 
quadruple the prices for the 2%x2 inch size : 

No. 25. Useful Metallic and Non-Metallic Minerals. 300 specimens, 
averaging 2%x2 in., $125.00. Includes various examples of all important 
minerals possessing economic value. 

No. 27. Metallurgical Collection. 200 specimens, averaging 2%x2 in., 
$90.00. Embraces the most important ores of common, rare or precious metals. 

No. 32. Ore Associations. 60 specimens, averaging 2%x2 in., $12.00. 
Includes all of the minerals most commonly found with valuable ores. 

No. 48. Collection Of Rocks. $6.00. 60 specimens, averaging 2%x2 in. 

No. 34b. Gold and Silver Ores. 25 specimens, averaging 2%x2 in., $25.00. 

Also larger series illustrating the occurrence of Iron, Lead, Copper, Zinc, 
Nickel, Cobalt, Uranium, Radium, Thorium and Rare Elements ; Rough 
Gems and Precious Stones. 

For Catalogs see next page. Minerals purchased in quantity. Send small mail 
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" Complete Mineral Catalog." 

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The most up-to-date compilation of the kind in print. The "Metallic 
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"Dana's Classification " is the most generally accepted mineralogi- 
cal system in Europe and America. Here is found name, composition and 
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mineral in this classification. 

Over 40 engravings of minerals, including one colored plate. 

Over lfiO pages of useful data for mining men. 

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C. E., F. R. S. Seventh Edition. Illustrated. 1 vol. i2mo. .60 

ARROWSMITH.— Paper-Hanger's Companion : 

A Treatise in which the Practical Operations of the Trade are 
Systematically laid down : with Copious Directions Preparatory to 
Papering; Preventives against the Effect of Damp on Walls; the 
various Cements and Pastes Adapted to the Several Purposes oi 
the Trade; Observations and Directions for the Panelling and 
Ornamenting of Rooms, etc. By James Arrowsmith. i2mo., 
cloth $1.00 

kSHTON. — The Theory and Practice of the Art of Designing 
Fancy Cotton and Woollen Cloths from Sample : 

Giving full instructions for reducing drafts, as well as the methods of 
spooling and making out harness for cross drafts and finding any re- 
quired reed; with calculations and tables of yarn. By Frederic T. 
Ashton, Designer, West Pittsfield, Mass. With fifty-two illustrations. 
One vol. folio $5.00 

ASKINSON. — Perfumes and their Preparation: 

A Comprehensive Treatise on Perfumery, containing Complete 
Directions for Making Handkerchief Perfumes, Smelling-Salts, 
Sachets, Fumigating Pastils ; Preparations for the Care of the Skin, 
the Mouth, the Hair; Cosmetics, Hair Dyes, and other Toilet 
Articles. By G. W. Askinson. Translated from the German by IsiDOR 
Furst. Revised by Charles Rice. 32 Illustrations. 8vo. $3.00 

BRONGNIART.— Coloring and Decoration of Ceramic Ware. 
8vo $2.00 

BAIRD. — The American Cotton Spinner, and Manager's and 
Carder's Guide: 

A Practical Treatise on Cotton Spinning ; giving the Dimensions and 
Speed of Machinery, Draught and Twist Calculations, etc. ; with 
notices of recent Improvements : together with Rules and Examples 
for making changes in the sizes and numbers of Roving and Yarn. 
Compiled from the papers of the late Robert H. Baird. iano. 



3AIR.D.— Standard Wages Computing Tables: 

An Improvement in all former Methods of Computation, so arrange^ 
that wages for days, hours, or fractions of hours, at a specified rate 
per day or hour, may be ascertained at a glance. By T. Spangler 
Baird. Oblong folio . . . . . . . $5.00 

BAKER. — Long-Span Railway Bridges: 
Comprising Investigations of the Comparative Theoretical and 
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B. Baker. 121110. $1.00 

BAKER. — The Mathematical Theory of the Steam-Engine: 
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Practical Men. By T. Baker, C. E., with numerous Diagrams. 
Sixth Edition, Revised by Prof. J. R. Young. i2mo. . 75 

BARLOW. — The History and Principles of Weaving, by 
Hand and by Power : 
Reprinted, with Considerable Additions, from " Engineering," with 
a chapter on Lace-making Machinery, reprinted from the Journal of 
the "Society of Arts." By Alfred Barlow. With several hundred 
illustrations. 8vo., 443 pages (Scarce.) 

BARR. — A Practical Treatise on the Combustion of Coal: 
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liquid or gaseous. 8vo. ....... $2.50 

BARR. — A Practical Treatise on High Pressure Steam Boilers : 
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together with a Description of Approved Safety Apparatus, Steam 
Pumps, Injectors and Economizers in actual use. By Wm. M. Barr. 
204 Illustrations. 8vo. ....... $3.00 

8AUERMAN.— A Treatise on the Metallurgy of Iron : 
Containing Outlines of the History of Iron Manufacture, Methods of 
Assay, and Analysis of Iron Ores, Processes of Manufacture of Iron 
and Steel, etc., etc. By H. Bauerman, F. G. S., Associate of the 
Royal School of Mines. Fifth Edition, Revised and Enlarged. 
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BRANNT.— The Metallic Alloys: A Practical Guide 

For the Manufacture of all kinds of Alloys, Amalgams, and Solders, 
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an Appendix on the Coloring of Alloys and the Recovery of Waste 
Metals. By William T. Brannt. 34 Engravings. A New, Re- 
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BEANS.— A Treatise on Railway Curves and Location of 
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By E. W. Beans, C. E. Illustrated. i2mo. Tucks . $1.50 

BECKETT.— A Rudimentary Treatise on Clocks, and Watches 

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"mo . | r .fio 


BELL. — Carpentry Made Easy: 

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BEMROSE. — Fret-Cutting and Perforated Carving: 

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BEMROSE. — Manual of Buhl-work and Marquetry: 

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BEMROSE.— Manual of Wood Carving: 

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BILLINGS.— Tobacco : 

Its History, Variety, Culture, Manufacture, Commerce, and Various 
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BIRD. — The American Practical Dyers' Companion: 
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BLINN. — A Practical Workshop Companion for Tin, Sheet- 
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BOOTH.— Marble Worker's Manual: 

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BOOTH and MORFIT. — The Encyclopaedia of Chemistry, 
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BRAM WELL.— The Wool Carder's Vade-Mecum* 

A Complete Manual of the Art of Carding Textile Fabrics. By W. 
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BRANNT.— A Practical Treatise on Animal and Vegetable 
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BRANNT.— A Practical Treatise on the Manufacture of Soap 
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comprising the Chemistry, Raw Materials, Machinery, and Utensils 
and Various Processes of Manufacture, including a great variety of 
formulas. Edited chiefly from the German of Dr. C. Deite, A. 
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of American Patents relating to these subjects. By Wm. T. Brannt. 
Illustrated by 163 engravings. 677 pages. 8vo. . . #7.50 

BRANNT.— India Rubber, Gutta Percha and Balata : 

Occurrence, Geographical Distribution, and Cultivation, Obtaining 
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them, Including Washing, Maceration, Mixing, Vulcanizing, Rubber 
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J2mo. 495 pages . . $2.o<3 

BROWN. — Five Hundred and Seven Mechanical Movements: 
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which have only recently come into use. By Henry T. Brown, 
i2mo $i.oo 

BUCKMASTER.— The Elements of Mechanical Physics: 
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i2mo $1.00 

9ULLOCK.— The American Cottage Builder : 
A Series of Designs, Plans and Specifications, from $200 to $20,000, 
for Homes for the People ; together with Warming, Ventilation, 
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BULLOCK.— The Rudiments of Architecture and Building: 
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BURGH.— Practical Rules for the Proportions of Modern 
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By N. P. Burgh, Engineer. i2mo. .... $1.50 

BYLES.— Sophisms of Free Trade and Popular Political 

Economy Examined. 

By a Barrister (Sir John Barnard Byles, Judge of Common 

Pleas). From the Ninth English Edition, as published by the 

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BO WM AN. —The Structure of the Wool Fibre in its Relation 
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8vo fe.ooi 

BYRNE. — Hand-Book for the Artisan, Mechanic, and Engi- 
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Comprising the Grinding and Sharpening of Cutting Tools, 
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8YRNE.— Pocket-Book for Railroad and Civil Engineers : 

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BYRNE.— The Practical Metal-Worker's Assistant : 
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Melting and Mixing; Casting and Founding ; Works in Sheet Metal; 
the Processes Dependent on the Ductility of the Metals; Soldering; 
and the most Improved Processes and Tools employed by Metal- 
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the works of Holtzapffel, Bergeron, Leupold, Plumier, Napier, 
Scoffern, Clay, Fairbairn and others. By Oliver Byrne. A new, 
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Improvements in Bessemer Steel. By A. A. Fesquet, Chemist- and 
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Branch of the Subject. 8vo #5-OC 

BYRNE.— The Practical Model Calculator: 
For the Engineer, Mechanic, Manufacturer of Engine Work, Naval 
Architect, Miner and Millwright. By Oliver Byrne. 8vo., nearly 
600 pages ......... &3-00 

Comprising a Collection of Designs for various Styles of Furniture. 
Illustrated by Forty-eight Large and Beautifully Engraved Plates. 
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CALLINGHAM.— Sign Writing and Glass Embossing: 

A Complete Practical Illustrated Manual of the Art. By James 
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Art of Letter Painting Made Easy. By James C. Badenoch. 258 
pages. i2mo. $1 .50 

CAMPIN. — A Practical Treatise on Mechanical Engineering: 
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shop Machinery, Mechanical Manipulation, Manufacture of Steam' 
Engines, etc. With an Appendix on the Analysis of Iron and Iron 
Ores. By Francis Campin, C. E. To which are added, Observations 
on the Construction of Steam Boilers, and Remarks upon Furnaces 
used for Smoke Prevention ; with a Chapter on Explosions. Bv R. 
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CAREY.— A Memoir of Henry C. Carey. 
By Dr. Wm. Elder. With a portrait. 8vo., cloth . . 75 

CAREY.— The Works of Henry C. Carey : 

Harmony of Interests : Agricultural, Manufacturing and Commer- 
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Manual of Social Science. Condensed from Carey's " Principles 
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Miscellaneous Works. With a Portrait. 2 vols. 8vo. #10.00 
Past, Present and Future. 8vo. ... . . . #2.50 

Principles of Social Science. 3 volumes, 8vo. . . $7.50 
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The Unity of Law : As Exhibited in the Relations of Physical, 
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CLARK. — Tramways, their Construction and Working : 

Embracing a Comprehensive History of the System. With an ex' 
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varieties of Rolling stock, and ample details of cost and working ex- 
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COLBURN.— The Locomotive Engine : 

Including a Description of its Structure, Rules for Estimating its 
Capabilities, and Practical Observations on its Construction and Man- 
agement. By Zerah Colburn. Illustrated. 121110. . #1.00 

ELLENS.— The Eden of Labor; or, the Christian Utopia. 
By T. Wharton Collens, author of " Humanics," " The Historj 
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^OOLEY. — A Complete Practical Treatise on Perfumery : 
Being a Hand-book of Perfumes, Cosmetics and other Toilet Articlet 
With a Comprehensive Collection of Formulae. By Arnold } 
Cooley. 121110 #i.fjo 

COOPER.- A Treatise on the use of Belting for the Trant- 
mission of Power. 
With numerous illustrations of approved and actual methods of ar 
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Belts. Descriptions of many varieties of Beltings, together witn 
chapters on the Transmission of Power by Ropes; by Iron and 
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on the Experimental Investigations of Morin, Briggs, and others. By 
John H. CoorER, M. E. 8vo #3-50 

CRAIK. — The Practical American Millwright and MUler. 
By David Craik, Millwright. Illustrated by numerous wood en 
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CROSS.— The Cotton Yarn Spinner: 

Showing how the Preparation should be arranged for Differem. 
Counts of Yarns by a System more uniform than has hitherto been 
practiced; by having a Standard Schedule from which we make all 
our Changes. By Richard Cross. 122 pp. i2mo. . 75 

CRISTIANI.— A Technical Treatise on Soap and Candles: 
With a Glance at the Industry of Fats and Oils. By R. S. Cris- 
tiani, Chemist. Author of " Perfumery and Kindred Arts." Illus- 
trated by 176 engravings. 581 pages, 8vo. $15.00 

COURTNEY.— The Boiler Maker's Assistant in Drawing, 
Templating, and Calculating Boiler Work and Tank 
Work, etc. 
Revised by D. K. Clark. 102 ills. Fifth edition. . . 80 
COURTNEY.— The Boiler Maker's Ready Reckoner: 

With Examples of Practical Geometry and Templating. Revised by 
D. K. CLARK, C. E. 37 illustrations. Fifth edition. • $1.60 

DAVIDSON.— A Practical Manual of House Painting, Grain- 
ing, Marbling, and Sign- Writing: 
Containing full information on the processes of House Painting in 
Oil and Distemper, the Formation of Letters and Practice of Sign- 
Writing, the Principles of Decorative Art, a Course of Elementary 
Drawing for House Painters, Writers, etc., and a Collection of Useful 
Receipts. With nine colored illustrations of Woods and Marbles, 
and numerous wood engravings. By Ellis A, Davidson. i2mo. 


DAVIES.— A Treatise on Earthy and Other Minerals and 
By D. C. Davies, F. G. S., Mining Engineer, etc. Illustrated by 
76 Engravings. l2mo. ....... $5.00 

DAVIES. — A Treatise on Metalliferous Minerals and Mining: 
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Quarries and Collieries. Illustrated by 148 engravings of Geological 
Formations, Mining Operations and Machinery, drawn from the 
practice of all parts of the world. Fifth Edition, thoroughly Revised 
and much Enlarged by his son, E. Henry Davies. i2mo., 524 
pages ....... . #5-oo 

DAVIES.— A Treatise on Slate and Slate Quarrying: 

Scientific, Practical and Commercial. By D C. Davies, F. G. S., 
Mining Engineer, etc. With numerous illustrations and folding 
plates. !2mo. $1.20 

DAVIS. — A Practical Treatise on the Manufacture of Brick, 

Tiles and Terra-Cotta : 

Including Stiff Clay, Dry Clay, Hand Made, Pressed or Front, and 

Roadway Paving Brick, Enamelled Brick, with Glazes and Colors, 

Fire Brick and Blocks, Silica Brick, Carbon Brick, Glass Pots, Re- 


torts, Architectural Terra-Cotta, Sewer Pipe, Drain Tile, Glazed and 
Unglazed Roofing Tile, Art Tile, Mosaics, and Imitation of Intarsia 
or Inlaid Surfaces. Comprising every product of Clay employed in 
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Description of the Different Clays employed, the Most Modern 
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Disintegrating, Tempering, and Moulding the Clay into Shape, Dry- 
ing, Setting, and Burning. By Charles Thomas Davis. Third Edi- 
tion. Revised and in great part rewritten. Illustrated by 261 
engravings. 662 pages . . . . . • . . $5 .00 

DAVIS. — A Treatise on Steam-Boiler Incrustation and Meth- 
ods for Preventing Corrosion and the Formation of Scale: 
By Charles T. Davis. Illustrated by 65 engravings. 8vo. 

DAVIS.— The Manufacture of Paper: 

Being a Description of the various Processes for the Fabrication, 
Coloring and Finishing of every kind of Paper, Including the Dif- 
ferent Raw Materials and the Methods for Determining their Values, 
the Tools, Machines and Practical Details connected with an intelli- 
gent and a profitable prosecution of the art, with special reference to 
the best American Practice. To which are added a History of Pa- 
per, complete Lists of Paper-Making Materials, List of American 
Machines, Tools and Processes used in treating the Raw Materials, 
and in Making, Coloring and Finishing Paper. By Charles T. 
Davis. Illustrated by 156 engravings. 608 pages, 8vo. $6.00 

DAVIS.— The Manufacture of Leather: 

Being a Description of all the Processes for the Tanning and Tawing 
with Bark, Extracts, Chrome and all Modern Tannages in General 
Use, and the Currying, Finishing and Dyeing of Every Kind of Leather ; 
Including the Various Raw Materials, the Tools, Machines, and all 
Details of Importance Connected with an Intelligent and Profitable 
Prosecution of the Art, with Special Reference to the Best American 
Practice. To which are added Lists of American Patents ( 1884-1897) 
for Materials, Processes, Tools and Machines for Tanning, Currying, 
etc. By Charles Thomas Davis. Second Edition, Revised, and 
in great part Rewritten. Illustrated by 147 engravings and 14 Sam- 
ples of Quebracho Tanned and Aniline Dyed Leathers. 8vo, cloth, 
712 pages. Price $7-5° 

DAWIDOWSKY— BRANNT.— A Practical Treatise on the 

Raw Materials and Fabrication of Glue, Gelatine, Gelatine 

Veneers and Foils, Isinglass, Cements, Pastes, Mucilages, 

etc. : 

Based upon Actual Experience. By F. Dawidowsky, Technical 

Chemist. Translated from the German, with extensive additions, 

including a description of the most Recent American Processes, by 

William T. Brannt, Graduate of the Royal Agricultural College 

of Eldena, Prussia. 35 Engravings. i2mo. . . . #2.50 

DE GRAFF.— The Geometrical Stair-Builders' Guide: 
Being a Plain Practical System of Hand-Railing, embracing all it9 
necessary Details, and Geometrically Illustrated by twenty-two Steel 
Engravings ; together with the use of the most approved principle? 
of Practical Geometry. By Simon De Graff, Architect (Scarce.) 


DE KONINCK— DIETZ.— A Practical Manual of Chemical 
Analysis and Assaying : 

As applied to the Manufacture of Iron from its Ores, and to Cast Iron, 
Wrought Iron, and Steel, as found in Commerce. By L. L. De 
Koninck, Dr. Sc, and E. Dietz, Engineer. Edited with Notes, by 
Robert Mallet, F. R. S., F. S. G., M. I. C. E., etc. American 
Edition, Edited with Notes and an Appendix on Iron Ores, by A. A. 
Fesquet, Chemist and Engineer. i2mo. . . . $1.50 

DUNCAN.— Practical Surveyor's Guide: 
Containing the necessary information to make any person of com 
mon capacity, a finished land surveyor without the aid of a teacher 
By Andrew Duncan. Revised. 72 engravings, 2,14 pp. i2mo. $1.50 

CUPLAIS. — A Treatise on the Manufacture and Distillation 
of Alcoholic Liquors : 
Comprising Accurate and Complete Details in Regard to Alcohol 
from Wine, Molasses, Beets, Grain, Rice, Potatoes, Sorghum, Aspho 
del, Fruits, etc. ; with the Distillation and Rectification of Brandy 
Whiskey, Rum, Gin, Swiss Absinthe, etc., the Preparation of Aro- 
matic Waters, Volatile Oils or Essences, Sugars, Syrups, Aromatic 
Tinctures, Liqueurs, Cordial Wines, Effervescing Wines, etc., the 
Ageing of Brandy and the improvement of Spirits, with Copious 
Directions and Tables for Testing and Reducing Spirituous Liquors, 
etc* etc. Translated and Edited from the French of MM. Duplais, 
By M. McKennie, M. D. Illustrated. 743 pp. 8vo. $15.00 


Containing upwards of two hundred Receipts for making Colors, on 
the most approved principles, for all the various styles and fabrics now 
in evistence ; with the Scouring Process, and plain Directions for 
Preparing, Washing-off, and Finishing the Goods. i2mo. $1 OO 

EIDHERR.— The Techno-Chemical Guide to Distillation: 
A Hand-Book for the Manufacture of Alcohol and Alcoholic Liquors, 
including the Preparation of Malt and Compressed Yeast. Edited 
from the German of Ed. Eidherr. Fully illustrated. (In preparation.) 

EDWARDS.— A Catechism of the Marine Steam-Engine, 
For the use of Engineers, Firemen, and Mechanics. A Practical 
Work for Practical Men. By Emory Edwards, Mechanical Engi- 
neer. Illustrated by sixty-three Engravings, including examples of 
the most modern Engines. Third edition, thoroughly revised, with 
much additional matter. 1 2 mo. 414 pages ... #2 00 

EDWARDS. — Modern American Locomotive Engines, 
Their Design, Construction and Management. By EMORY EDWARDS* 
Illustrated i2mo #2.00 

EDWARDS.— The American Steam Engineer: 

Theoretical and Practical, with examples of the latest and most ap- 
proved American practice in the design and construction of Steam 
Engines and Boilers. For the use of engineers, machinists, boiler- 
uvikers, and engineering students. By Emory Edwards. Fully 
mustrated, 419 pages. i2mo. • $2jjo 


EDWARDS. — Modern American Marine Engines, Boilers, and 
Screw Propellers, 

Their Design and Construction. Showing the Present Practice of 
the most Eminent Engineers and Marine Engine Builders in the 
United States. Illustrated by 30 large and elaborate plates. 4to. $5.00 
EDWARDS.— The Practical Steam Engineer's Guide 

In the Design, Construction, and Management of American Stationary, 
Portable, and Steam Fire- Engines, Steam Pumps, Boilers, Injectors, 
Governors, Indicators, Pistons and Rings, Safety Valves and Steam 
Gauges. For the use of Engineers, Firemen, and Steam Users. By 
Emory Edwards. Illustrated by 119 engravings. 420 pages. 
i2mo #2 50 

EISSLER.— The Metallurgy of Gold : 
A Practical Treatise on the Metallurgical Treatment of Gold-Bear- 
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and the Assaying, Melting, and Refining of Gold. By M. Eissler. 

With 132 Illustrations. i2mo #7«50 

EISSLER.— The Metallurgy of Silver : 

A Practical Treatise on the Amalgamation, Roasting, and Lixiviation 
of Silver Ores, including the Assaying, Melting, and Refining of 
Silver Bullion. By M. Eissler. 124 Illustrations. 336 pp. 
i2mo. .......... $4.25 

ELDER. — Conversations on the Principal Subjects of Political 

By Dr. William Elder. 8vo #2.50 

ELDER.— Questions of the Day, 

Economic and Social. By Dr. William Elder. 8vo. . $3.00 
ERNI AND BROWN.— Mineralogy Simplified. 

Easy Methods of Identifying Minerals, including Ores, by Means of 
the Blow-pipe, by Flame Reactions, by Humid Chemical Analysis, 
and by Physical Tests. By Henri Erni, A. M., M. D. Third Edi- 
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including Tables for the Determination of Minerals by Chemical and 
Pyrognostic Characters, and by Physical Characters. By Amos P. 
Brown, E. M., Ph. D. 350 pp., illustrated by 96 engravings, pocket- 
book form, full flexible morocco, gilt edges . . . #2.50 
FAIRBAIRN.— The Principles of Mechanism and Machinery 
of Transmission • 
Comprising the Principles of Mechanism, Wheels, and Pulleys, 
Strength and Proportions of Shafts, Coupling of Shafts, and Engag- 
ing and Disengaging Gear. By Sir William Fairbairn, Bart 
C. E. Beautifully illustrated by over 150 wood-cuts. In one 

volume. i2mo ." . $2.00 

FLEMING.— Narrow Gauge Railways in America. 
A Sketch of their Rise, Progress, and Success. Valuable Statistics 
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Howard Fleming. Illustrated, 8vo |i 00 

FORSYTH.— Book of Designs for Headstones, Mural, and 
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Containing 78 Designs. By James Forsyth. With an Introduction 
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FRANKEL— HUTTER.— A Practical Treatise on the Manu* 
facture of Starch, Glucose, Starch-Sugar, and Dextrine: 
Based on the German of Ladislaus Von Wagner, Professor in the 
Royal Technical High School, Buda-Pest, Hungary, and other 
authorities. By Julius Frankel, Graduate of the Polytechnic 
School of Hanover. Edited by Robert Hutter, Chemist, Practical 
Manufacturer of Starch- Sugar. Illustrated by 58 engravings, cover- 
ing every branch of the subject, including examples of the most 
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GARDNER.— The Painter's Encyclopaedia: 
Containing Definitions of all Important Words in the Art of Plain 
and Artistic Painting, with Details of Practice in Coach, Carriage, 
Railway Car, House, Sign, and Ornamental Painting, including 
Graining, Marbling, Staining, Varnishing, Polishing, Lettering, 
Stenciling, Gilding, Bronzing, etc. By Franklin B. Gardner. 
158 Illustrations. l2mo. 427 pp $2.oc 

GARDNER.— Everybody's Paint Book : 

A Complete Guide to the Art of Outdoor and Indoor Painting. 38 
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GEE. — The Jeweller's Assistant in the Art of Working in 
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GEE.— The Goldsmith's Handbook : 

Containing full instructions for the Alloying and Working of Gold, 
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GEE.— The Silversmith's Handbook : 

Containing full instructions for the Alloying and Working of Silver, 
including the different modes of Refininrr and Melting the Metal; its 
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Memoranda. By George E. Gee. Illustrated. i2mo. Si. 25 


Designs for Gothic Furniture. Twenty-three plates. Oblong $1.50 

GRANT. —A Handbook on the Teeth of Gears : 
Their Curves, Properties, and Practical Construction. By George 
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GREENWOOD.— Steel and Iron : 

Comprising the Practice and Theory of the Several Methods Pur- 
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GREGORY. — Mathematics for Practical Men : 

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GRISWOLD. — Railroad Engineer's Pocket Companion for tht 
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'GRUNER. — Studies of Blast Furnace Phenomena: 

By M. L. Gruner, President of the General Council of Mines 0$ 
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Hand-Book of Useful Tables for the Lumberman, Farmer and 
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32 mo., boards. 186 pages .25 

HASERICK.— The Secrets of the Art of Dyeing Wool, Cotton* 
and Linen, 
Including Bleaching and Coloring Wool and Cotton Hosiery and 
Random Yarns. A Treatise based on Economy and Practice. By 
E. C. Haserick. Illustrated by 323 Dyed Patterns of the Yarm 
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A Practical Treatise on their Manufacture. By a Practical Hatter, 
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HERMANN. — Painting oh Glass and Porcelain, and Enamel 
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HAUPT.— Street Railway Motors: 

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HAUPT. — A Manual of Engineering Specifications and Con- 

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HAUPT.— The Topographer, His Instruments and Methods. 
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HUGHES. — American Miller and Millwright's Assistant: 
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HULME. — Worked Examination Questions in Plane Geomet- 
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For the Use of Candidates for the Royal Military Academy, Wool- 
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JERVIS.— Railroad Property: 

A Treatise on the Construction and Management of Railways; 
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KEENE.— A Hand-Book of Practical Gauging: 

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KELLEY.— Speeches, Addresses, and Letters on Industrial and 
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By Hon. William D. Kelley, M. C. 544 pages, 8vo. . $2.50 

KELLOGG.— A New Monetary System : 
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KEMLO.— Watch- Repairer's Hand-Book : 
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KENTISH.— A Treatise on a Box of Instruments, 
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KERL— The Assayer's Manual: 

An Abridged Treatise on the Docimastic Examination of Ores, and 
Furnace and other Artificial Products. By Bruno Kerl, Professor 
in the Royal School of Mines. Translated from the German by 
William T. Brannt. Second American edition, edited with Ex- 
tensive Additions by F. Lynwood Garrison, Men>ber of the 
American Institute of Mining Engineers, etc. Illustrated by 87 en- 
gravings. 8vo. (Scarce.^) 

KICK.— Flour Manufacture . 
A Treatise on Milling Science and Practice. By Frederick Kick 
Imperial Regierungsrath, Professor of Mechanical Technology in tht 
Imperial German Polytechnic Institute, Prague. Translated from 
the second enlarged and revised edition with supplement by H. H. 
P. Powles, Assoc. Memb. Institution of Civil Engineers. Illustrated 
with 28 Plates, and 167 Wood-cuts. 367 pages. 8vo. . #10.00 

KINGZETT.— The History, Products, and Processes of the 
Alkali Trade : 
Including the most Recent Improvements. By Charles Thomas 
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KIRK.— The Cupola Furnace : 

A Practical Treatise on the Construction and Management of Foundry 
Cupolas. By Edward Kirk, Practical Moulder and Melter, Con- 
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LANDRIN.— A Treatise on Steel : 

Comprising its Theory, Metallurgy, Properties, Practical Working, 
and Use. By M. H. C. Landrin, Jr. From the French, by A. A. 
Fesquet. i2mo $2.50 

LANGBEIN.— A Complete Treatise on the Electro-Deposi. 
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Comprising Electro-Plating and Galvanoplastic Operations, the De- 
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ing of Metals, the Methods of Grinding and Polishing, as well as 
Descriptions of the Electric Elements, Dynamo-Electric Machines, 
Thevmo-Piles and of the Materials and Processes used in Every De- 
partment of the Art. From the German of Dr. George Langbein, 
with additions by Wm. T. Brannt. Fourth Edition, thoroughly revised 
and much enlarged. 150 Engravings. 590 pages. 8vo. 1902. $4.00 

LARDNER.— The Steam-Engine : 
For the Use of Beginners. Illustrated. i2mo. • • • .60 

LEHNER.— The Manufacture of Ink: 
Comprising the Raw Materials, and the Preparation df W«iting, 
Copying and Hektograph Inks, Safety Inks, Ink Extracts and Pow- 
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LARKIN* — The Practical Brass and Iron Founder's Guide 1 
A Concise Treatise on Brass Founding, Moulding, the Metals and 
their Alloys, etc. ; to which are added Recent Improvements in the 
Manufacture of Iron, Steel by the Bessemer Process, etc., etc. Bj 
Tames Larkin, late Conductor of the Brass Foundry Department ia 
Keany, Neafie & Co.'s Penn Works, Philadelphia. New edition, 
revised, with extensive additions. 414 pages. 121x10. . $2.50 

LEROUX.— A Practical Treatise on the Manufacture 0$ 
Worsteds and Carded Yarns : 
Comprising Practical Mechanics, with Rules and Calculations applied 
to Spinning ; Sorting, Cleaning, and Scouring Wools ; the English 
and French Methods of Combing, Drawing, and Spinning Worsteds, 
and Manufacturing Carded Yarns. Translated from the French of 
Charles Leroux, Mechanical Engineer and Superintendent of a 
9pinning-Mill, by Horatio Paine, M. D., and A. A. Fesquet, 
Chemist and Engineer. Illustrated by twelve large Plates. To which 
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International Jury, and of the Artisans selected by the Committe* 
appointed by the Council of the Society of Arts, London, on Woolec 
and Worsted Machinery and Fabrics, as exhibited in the Paris Uni« 
versal Exposition, 1867. 8vo. ..... $5.00 

LEFFEL. — The Construction of Mill-Dams : 
Comprising also the Building of Race and Reservoir Embankments 
and Head-Gates, the Measurement of Streams, Gauging of Water 
Supply, etc. By James Leffel & Co. Illustrated by 58 engravings. 
8vo. $2.50 

LESLIE.— Complete Cookery: 
Directions for Cookery in its Various Branches. By Miss Leslie. 
Sixtieth thousand. Thoroughly revised, with the addition of New 
Receipts. 121110. . . #1-5° 

LE VAN.— The Steam Engine and the Indicator : 

Their Origin and Progressive Development ; including the Most 
Recent Examples of Steam and Gas Motors, together with the Indi- 
cator, its Principles, its Utility, and its Application. By William 
Barnet Le Van. Illustrated by 205 Engravings, chiefly of Indi- 
cator-Cards. 469 pp. 8vo $4.00 

LIEBER.— Assayer's Guide : 
Or, Practical Directions to Assayers, Miners, and Smelters, for the 
Tests and Assays, by Heat and by Wet Processes, for the Ores of all 
ty principal Metals, of Gold and Silver Coins aad Alloys, and of 
Coal, etc. By Oscar M. Lieber. Revised. 283 pp. i2mo. $1.50 

Lockwood's Dictionary of Terms : 

Used in the Practice of Mechanical Engineering, embracing those 
Current in the Drawing Office, Pattern Shop, Foundry, Fitting, Turn- 
ing, Smith's and Boiler Shops, etc., etc., comprising upwards of Six 
Thousand Definitions. Edited by a Foreman Pattern Maker, author 
tj " Patterr Making." 417 pp. i2mo. , . . $$.75 


LUKIN.— The Lathe and Its Uses : 

Or Instruction in the Art of Turning Wood and Metal. Including 
a Description of the Most Modern Appliances for the Ornamentation 
of Plane and Curved Surfaces, an Entirely Novel Form of Lathe 
for Eccentric and Rose-Engine Turning; A Lathe and Planing 
Machine Combined; and Other Valuable Matter Relating to the 
Art. Illustrated by 462 engravings. Seventh edition. 315 pages. 
8vo #4.25 

MAIN and BROWN.— Questions on Subjects Connected with 
the Marine Steam-Engine : 

And Examination Papers; with Hints for their Solution. By 
Thomas J. Main, Professor of Mathematics, Royal ^aval College, 
and Thomas Brown, Chief Engineer, R. N. i2mo., cloth . #1.00 

MAIN and BROWN. — The Indicator and Dynamometer: 
With their Practical Applications to the Steam-Engine. By THOMAS 
J. Main, M. A. F. R., Ass't S. Professor Royal Naval College, 
Portsmouth, and Thomas Brown, Assoc. Inst. C. E., Chief Engineer 
R. N., attached to the R. N. College. Illustrated. 8vo. . 

MAIN and BROWN.— The Marine Steam-Engine. 
By Thomas J. Main, F. R. Ass't S. Mathematical Professor at the 
Royal Naval College, Portsmouth, and Thomas Brown, Assoc. 
Inst. C. E., Chief Engineer R. N. Attached to the Royal Naval 
College. With numerous illustrations. 8vo. 

MAKINS.— A Manual of Metallurgy: 

By George Hogarth Makins. 100 engravings. Second edition 
rewritten and much enlarged. i2mo.. 592 pages 

MARTIN.— Screw-Cutting Tables, for the Use of Mechanic*) 
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Showing the Proper Arrangement of Wheels for Cutting the Threads 
of Screws of any Required Pitch ; with a Table for Making the Uni- 
versal Gas-Pipe Thread and Taps. By W. A. Martin, Engineer. 
8vo -5o 

MICH ELL — Mine Drainage: 
Being a Complete and Practical Treatise on Direct-Acting Under 
ground Steam Pumping Machinery. With a Description of a largt 
number of the best known Engines, their General Utility and ihe 
Special Sphere of their Action, the Mode of their Application, and 
their Merits compared with other Pumping Machinery. By Stephen 
Michell. Illustrated by 247 engravings. 8vo., 369 pages. $12 50 

MOLESWORTH.— Pocket-Book of Useful Formulae and 
Memoranda for Civil and Mechanical Engineers. 
By Guilford L. Molesworth, Member of the Institution of Civil 
Engineers, Chief Resident Engineer of the Ceylon Railway. Full- 
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MOORE.— The Universal Assistant and the Complete Ml 
chanic : 

Containing over one million Industrial Facts, Calculations, Receipt*. 
Processes, Trades Secrets, Rules, Business Forms, Legal Items, Etc., 
in every occupation, from the Household to the Manufactory. By 
R. Moore. Illustrated by 500 Engravings. i2mo. . $2.50 

MORRIS. — Easy Rules for the Measurement of Earthworks : 
By means of the Prismoidal Formula. Illustrated with Numerouf 
Wood-Cuts, Problems, and Examples, and concluded by an Exten 
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The whole being adapted for convenient use by Engineers, Surveyors! 
Contractors, and others needing Correct Measurements of Earthwork 

By Elwood Morris, C. E. 8vo #1.50 

MAUCHLINE.— The Mine Foreman's Hand-Book 

Of Practical and Theoretical Information on the Opening, Venti- 
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Others in Passing Examinations for Mine Foremanships. By 
Robert Mauchline, Ex-Inspector of Mines. A New, Revised and 
Enlarged Edition. Illustrated by 114 engrarings. 8vo. 337 
pages .......... #3-75 

NAPIER. — A System of Chemistry Applied to Dyeing. 
By James Napier, F. C. S. A New and Thoroughly Revised Edi- 
tion. Completely brought up to the present state of the Science, 
including the Chemistry of Coal Tar Colors, by A. A. Fesquet, 
Chemist and Engineer. With an Appendix on Dyeing and Ca)ica 
Printing, as shown at the Universal Exposition, Paris, 1867. Illus- 
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NEVILLE.— Hydraulic Tables, Coefficients, and Formulae, fot 
finding the Discharge of Water from Orifices, Notches, 
Weirs, Pipes, and Rivers : 
Third Edition, with Additions, consisting of New Formulae for the 
Discharge from Tidal and Flood Sluices and Siphons ; general infor 
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Supply for Towns and Mill Power. By Tohn Neville, C. E. M R 
I. A. ; Fellow of the Royal Geological Society of Ireland. Thick 

l2mo £5.50 

NEWBERY.— Gleanings from Ornamental Art of every 
style : 
Drawn from Examples in the British, South Kensington, Indian, 
Crystal Palace, and other Museums, the Exhibitions of 1851 and 
1862, and the best English and Foreign works. In a series of 100 
exquisitely drawn Plates, containing many hundred examples. By 

Robert Newbery. 4to. (Scarce.) 

NICHOLLS.— The Theoretical and Practical Boiler- M aker and 
Engineer's Reference Book: 
Containing a variety of Useful Information for Employers of Labor 
Foremen a'\d Working Boiler-Makers. Iron, Copper, and Tinsnuth* 


Draughtsmen, Engineers, the General Steam- using Public, and for the 
Use of Science Schools and Classes. By Samuel NiCHOLLS. Illus* 
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NICHOLSON.— A Manual of the Art of Bookbinding : 
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NICOLLS.— The Railway Builder: 
A Hand-Book for Estimating the Probable Cost of American Rail- 
way Construction and Equipment. By William J. Nicolls, Civil 
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NORMANDY.— The Commercial Handbook of Chemical An- 
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Or Practical Instructions for the Determination of the Intrinsic 01 
Commercial Value of Substances used in Manufactures, in Trades, 
and in the Arts. By A. Normandy. New Edition, Enlarged, and 
to a great extent rewritten. By Henry M. Noad, Ph.D., F.R.S., 
thick i2mo Scarce 

NORRIS. — A Handbook for Locomotive Engineers and Ma- 
chinists : 
Comprising the Proportions and Calculations for Constructing Loco- 
motives; Manner of Setting Valves; Tables of Squares, Cubes, Areas, 
etc., etc. By Septimus Norris, M. E. New edition. Illustrated, 
I2mo. $1.50 

NYSTROM. — A New Treatise on Elements of Mechanics : 
Establishing Strict Precision in the Meaning of Dynamical Terms 1 
accompanied with an Appendix on Duodenal Arithmetic and Me* 
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NYSTROM. — On Technological Education and the Construc- 
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For Naval and Marine Engineers. By John W. Nystrom, IaU 
Acting Chief Engineer, U. S. N. Second edition, revised, with addi 
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O'NEILL. — A Dictionary of Dyeing and Calico Printing: 
Containing a brief account of all the Substances and Processes in 
use in the Art of Dyeing and Printing Textile Fabrics ; with Practical 
Receipts and Scientific Information. By Charles O'Neill, Analy- 
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their application to Dyeing and Calico Printing. By A. A. Fesquet, 
Chemist and Engineer. With an appendix on Dyeing and Calico 
Printing, as shown at the Universal Exposition, Paris, 1867- 8vo., 

491 pages . $3.00 

•RTON. — Underground Treasures-. 

How and Where to Find Them. A Key for the Ready Determination 
of all the Useful Minerals within the United States. By James 
OrTON, A.M., Late Professor of Natural History in Vassar College, 
N. Y.; author of the "Andes and the Amazon," etc. A New Edi- 
tion, with An Appendix on Ore Deposits and Testing Minerals (1901). 
Illustrated , $1-50 


OSBORN.— The Prospector's Field Book and Guide. 

In the Search For and the Easy Determination of Ores and Other 
Useful Minerals. By Prof. H. S. Osborn, LL. D. Illustrated by 58 
Engravings. i2mo. Fifth Edition. Revised and Enlarged 

( iq oi) I1.50 

OSBORN — A Practical Manual of Minerals, Mines and Min- 
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Chemical Analysis and Assay ; together with Various Systems of Ex- 
cavating and Timbering, Brick and Masonry Work, during Driving, 
Lining, Bracing and other Operations, etc. By Prof. H. S. Osborn, 
LL. D., Author of « The Prospector's Field-Book and Guide." 171 
engravings. Second Edition, revised. 8vo. . . . $4.50 
OVERMAN.— The Manufacture of Steel : 
Containing the Practice and Principles of Working and Making Steel. 
A Handbook for Blacksmiths and Workers in Steel and Iron, Wagon 
Makers, Die Sinkers, Cutlers, and Manufacturers of Files and Hard- 
ware, of Steel and Iron, and for Men of Science and Art. By 
Frederick Overman, Mining Engineer, Author of the " Manu- 
facture of Iron," etc. A new, enlarged, and revised Edition. By 
A. A. Fesql'£T, Chemist and Engineer. i2mo. . . $1.50 
OVERMAN.— The Moulder's and Founder's Pocket Guide : 
A Treatise on Moulding and Founding in Green-sand, Dry-sand, Loam, 
and Cement; the Moulding of Machine Frames, Mill-gear, Hollow* 
ware, Ornaments, Trinkets, Bells, and Statues; Description of Moulds 
for Iron, Bronze, Brass, and other Metals; Plaster of Paris, Sulphur, 
Wax, etc. ; the Construction of Melting Furnaces, the Melting and 
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Lacquers, Printing Inks and Sealing Waxes." Illustrated. 395 pp. 

121110. , $1 .50 

PALLETT.— The Miller's, Millwright's, and Engineer's Guide. 
By Henry Pallett. Illustrated. i2mo. . . . #2.00 


PERCY.— The Manufacture of Russian Sheet-Iron. 
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PERKINS.— Gas and Ventilation: 

Practical Treatise on Gas and Ventilation. Illustrated. I2mo. $1.25 

PERKINS AND STOWE.-A New Guide to the Sheet-iron 
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sheet, and the Thickness on the Wire Gauge of Sheet-iron of various 
dimensions to weigh 112 lbs. per bundle; and the conversion of 
Short Weight into Long Weight, and Long Weight into Short. 


POSSELT. — Recent Improvements in Textile Machinery Re- 
lating to Weaving : 
Giving the Most Modern Points on the Construction of all Kinds 
of Looms, Warpers, Beamers, Slashers, Winders, Spoolers, Reeds, 
Temples, Shuttles, Bobbins, Heddles, Heddle Frames, Pickers, 
Jacquards, Card Stampers, etc., etc. 600 illus. . . $3 00 

POSSELT.— Technology of Textile Design: 
The Most Complete Treatise on the Construction and Application 
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A. Posselt. 1,500 illustrations. 4to $5-00 

POSSELT. — Textile Calculations: 

A Guide to Calculations Relating to the Manufacture of all Kinds 
of Yarns and Fabrics, the Analysis of Cloth, Speed, Power and Belt 
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REGNAULT.— Elements of Chemistry: 
By M. V. Regnault. Translated from the French by T. Forrest 
Betton, M. D., and edited, with Notes, by James C. Booth, Melter 
and Refiner U. S. Mint, and William L. Faber, Metallurgist and 
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RICHARDS.— Aluminium : 

Its History, Occurrence, Properties, Metallurgy and Applications, 
including its Alloys. By Joseph W. Richards, A. C, Chemist and 
Practical Metallurgist, Member of the Deutsche Chemische Gesell- 
schaft. lllusr. Third edition, enlarged and revised (1895) . #6.00 

Treatise on the Manufacture of Colors for Painting: 
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the Necessary Apparatus and Directions for its Use; Dryers; the 
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ROPER. — Catechism for Steam Engineers and Electricians: 

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ROPER.— Engineer's Handy Book: 

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Stephen Roper. 15th edition. Revised and enlarged by E. R. 
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ROPER. — Hand-Book of Land and Marine Engines : 
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ROPER.— Hand-Book of the Locomotive : 

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ROPER.— Hand-Book of Modern Steam Fire- Engines. 
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ROPER. — Questions and Answers for Engineers. 

This little book contains all the Questions that Engineers will be 
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ROPER.— Use and Abuse of the Steam Boiler. 
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ROSE.— The Complete Practical Machinist : 

Embracing Lathe Work, Vise Work, Drills and Drilling, Taps and 
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ROSE.— Mechanical Drawing Self-Taught : 

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ROSS. — The Blowpipe in Chemistry, Mineralogy and Geology: 

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SHUNK. — A Practical Treatise on Railway Curves and Loca- 
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SHERRATT.— The Elements of Hand-Railing : 

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TEMPLETON.— The Practical Examinator on Steam and thd 

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THAUSING.— The Theory and Practice of the Preparation of 
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THOMPSON.— Political Economy. With Especial Reference 
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VAILE. — Galvanized-Iron Cornice-Worker's Manual : 

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VILLE. — On Artificial Manures : 
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WALTON.— Coal-Mining Described and Illustrated: 
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WARE.— The Sugar Beet. 
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of the Sugar Beet, Examination, Soils, Tillage, Seeds and Sowing 
Yield and Cost of Cultivation, Harvesting, Transportation, Conserva 
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WARN.— The Sheet-Metal Worker's Instructor: 

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WARNER.— New Theorems, Tables, and Diagrams, for the 
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WILSON. — Carpentry and Joinery: 

By John Wilson, Lecturer on Building Construction, Carpentry and 
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WATSON.— A Manual of the Hand-Lathe : 

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WATSON.— The Modern Practice of American Machinists and 
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with Workshop Management, Economy of Manufacture, the Steam 
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WATT.— The Art of Soap Making : 

A Practical Hand-Book of the Manufacture of Hard and Soft Soaps, 
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111. 121110 $3.00 

WEATHERLY.- Treatise on the Art of Boiling Sugar, Crys- 
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And other processes for Confectionery, etc., in which are explained, 
in an easy and familiar manner, the various Methods of Manufactur- 
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WILL,. — Tables of Qualitative Chemical Analysis : 

With an Introductory Chapter on the Course of Analysis. By Pro- 
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Pa. 8vo $1.50 

WILLIAMS.— On Heat and Steam : 

Embracing New Views of Vaporization, Condensation and Explo- 
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WILSON. — First Principles of Political Economy: 

With Reference to Statesmanship and the Progress of Civilization. 
By Professor W. D. Wilson, of the Cornell University. A new and 
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WILSON.— The Practical Tool-Maker and Designer: 

A Treatise upon the Designing of Tools and Fixtures for Machine 
Tools and Metal Working Machinery, Comprising Modern Examples 
of Machines with Fundamental Designs for Tools for the Actual Pro- 
duction of the work; Together with Special Reference to a Set of 
Tools for Machining the Various Parts of a Bicycle. Illustrated by 
189 engravings. 1898 $2.50 

CONTENTS : Introductory. Chapter I. Modern Tool Room and Equipment. 
II. Files, Their Use and Abuse. III. Steel and Tempering. IV. Making Jigs. 
V. Milling Machine fixtures. VI. Tools and Fixtures for Screw Machines. VII. 
Broaching. VIII. Punches and Dies for Cutting and Drop Press. IX. Tools for 
Hollow- Ware. X. Embossing: Metal, Coin, and Stamped Sheet-Metal Orna- 
ments. XI. Drop Forging. XII. Solid Drawn Shells or Ferrules; Cupping or 
Cutting, and Drawing ; Breaking Down Shells. XIII. Annealing, Pickling and 
Cleaning. XIV. Tools for Draw Bench. XV. Cutting and Assembling Pieces 
by Means of Ratchet Dial Plates at One Operation. XVI. The Header. XVII. 
Tools for Fox Lathe. XVIII. Suggestions for a Set of Tools for Machining the 
Various Parts of a Bicycle. XIX. The Plater's Dynamo. XX. Conclusion — 
With a Few Random Ideas. Appendix. Index. 

WOODS. — Compound Locomotives: 

By Arthur Tannatt Woods. Second edition, revised and enlarged 
by David Leonard Barnes, A. M., C. E. 8vo. 330 pp. #3.00 


WOHLER.-A Hand-Bookof Mineral Analysis: 

By F. Wohler, Professor of Chemistry in the University of Gotthv 
gen. Edited by Henry B. Nason, Professor of Chemistry in the 
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WORSSAM.— On Mechanical Saws: 

From the Transactions of the Society of Engineers. 1869. By S. W. 
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BRANNT. — Varnishes, Lacquers, Printing Inks and Sealing - 
Waxes : 
Their Raw Materials and their Manufacture, to which is added the 
Art of Varnishing and Lacquering, including the Preparation of Put- 
ties and of Stains for Wood, Ivory, Bone, Horn, and Leather. By 
William T. Brannt. Illustrated by 39 Engravings, 338 pages. 
i2mo #3.00 

BRANNT— The Practical Scourer and Garment Dyer: 

Comprising Dry or Chemical Cleaning; the Art of Removing Stains; 
Fine Washing ; Bleaching and Dyeing of Straw Hats, Gloves, and 
Feathers of all kinds; Dyeing of Worn Clothes of all fabrics, in- 
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and Fluids for Cleansing Purposes. Edited by William T. Brannt, 
Editor of "The Techno-Chemical Receipt Book." Illustrated. 
203 pages. i2mo. $2.00 

BRANNT.— Petroleum . 

its History, Origin, Occurrence, Production, Physical and Chemical 
Constitution, Technology, Examination and Uses; Together with 
the Occurrence and Uses of Natural Gas. Edited chiefly from the 
German of Prof. Hans Hoefer and Dr. Alexander Veith, by Wm. 
T. Brannt. Illustrated by 3 Plates and 284 Engravings. 743 pp. 
8vo. #7-50 

BRANNT. — A Practical Treatise on the Manufacture of Vine- 
gar and Acetates, Cider, and Fruit- Wines : 
Preservation of Fruits and Vegetables by Canning and Evaporation ; 
Preparation of Fruit-Butters, Jellies, Marmalades, Catchups, Pickles, 
Mustards, etc. Edited from various sources. By William T. 
Brannt. Illustrated by 79 Engravings. 479 pp. 8vo. #6.00 

BRANNT.— The Metal Worker's Handy-Book of Receipts 
and Processes : 
Being a Collection of Chemical Formulas and Practical Manipula- 
tions for the working of all Metals ; including the Decoration and 
Beautifying of Articles Manufactured therefrom, as well as their 
Preservation. Edited from various sources. By Willi AM T. 
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DEITE. — A Practical Treatise on the Manufacture of Per- 
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Comprising directions for making all kinds of Perfumes, Sachet 
Powders, Fumigating Materials, Dentifrices, Cosmetics, etc., with a 
full account of the Volatile Oils, Balsams, Resins, and other Natural 
and Artificial Perfume-substances, including the Manufacture of 
Fruit Ethers, and tests of their purity. By Dr. C. Deite, assisted 
by L. Borchert, F. Eichbaum, E. Kugler, H. Toeffner, and 
other experts. From the German, by Wm. T. Brannt. 28 Engrav- 
ings. 358 pages. 8vo. $3-°o 

EDWARDS. — American Marine Engineer, Theoretical and 
Practical : 
With Examples of the latest and most approved American Practice. 
By Emory Edwards. 85 illustrations. i2mo. . . $2.50 

EDWARDS. — 900 Examination Questions and Answers: 

For Engineers and Firemen (Land and Marine) who desire to ob- 
tain a United States Government or State License. Pocket-book 

form, gilt edge $1-5° 

FLEMMING.- Practical Tanning: 

A Handbook of Modern Processes, Receipts, and Suggestions for the 
Treatment of Hides, Skins, and Pelts of Every Description. By 
Lewis A. Flemming. American Tanner. 472 pp. 8 vo. (1903) #4.00. 

POSSELT. — The Jacquard Machine Analysed and Explained: 

With an Appendix on the Preparation of Jacquard Cards, and 
Practical Hints to Learners of Jacquard Designing. By E. A. 
Posselt. With 230 illustrations and numerous diagrams. 127 pp. 
4to. $3-0O 

POSSELT.— The Structure of Fibres, Yarns and Fabrics: 

Being a Practical Treatise for the Use of all Persons Employed in 
the Manufacture of Textile Fabrics, containing a Description of the 
Growth and Manipulation of Cotton, Wool, Worsted, Silk Flax, 
Jute, Ramie, China Grass and Hemp, and Dealing with all Manu- 
facturers' Calculations for Every Class of Material, also Giving 
Minute Details for the Structure of all kinds of Textile Fabrics, and 
an Appendix of Arithmetic, specially adapted for Textile Purposes. 
By E. A. Posselt. Over 400 Illustrations, quarto. . $5-oo 

RICH. — Artistic Horse-Shoeing: 

A Practical and Scientific Treatise, giving Improved Methods of 
Shoeing, with Special Directions for Shaping Shoes to Cure Different 
Diseases of the Foot, and for the Correction of Faulty Action in 
Trotters. By George E. Rich. 62 Illustrations. 153 pages, 
lamo. $1.00 


RICHARDSON.— Practical Blacksmithing : 

A Collection of Articles Contributed at Different Times by Skilled 
Workmen to the columns of " The Blacksmith and Wheelwright," 
and Covering nearly the Whole Range of Blacksmithing, from the 
Simplest Job of Work to some of the Most Complex Forgings. 
Compiled and Edited by M. T. Richardson. 

Vol.1. 210 Illustrations. 224 pages. i2mo. . . $1.00 

Vol.11. 230 Illustrations. 262 pages. i2mo. . . #1.00 
Vol. III. 390 Illustrations. 307 pages. i2mo. , . $1.00 
Vol. IV. 226 Illustrations. 276 pages. l2mo. , . #1.00 

RICHARDSON.— The Practical Horseshocr: 
Being a Collection of Articles on Horseshoeing in all its Branches* 
which have appeared from time to time in the columns of " T he 
Blacksmith and Wheelwright," etc. Compiled and edited by M. T. 
Richardson. 174 illustrations #1.00 

ROPER. — Instructions and Suggestions for Engineers and 
Firemen : 
By Stephen Roper, Engineer. i8mo. Morocco . $2.00 

ROPER.— The Steam Boiler: Its Care and Management: 
By Stephen Roper, Engineer. i2mo., tuck, gilt edges. #2.00 

ROPER.— The Young Engineer's Own Book: 

Containing an Explanation of the Principle and Theories on which 
the Steam Engine as a Prime Mover is Based. By Stephen Roper, 
Engineer. 160 illustrations, 363 pages. i8mo., tuck . $2.50 

ROSE. — Modern Steam- Engines: 
An Elementary Treatise upon the Steam-Engine, written in Plain 
language ; for Use in the Workshop as well as in the Drawing Office. 
Giving Full Explanation j of the Construction of Modern Steanv 
Engines : Including Diagrams showing their Actual operation. To- 
gether with Complete but Simple Explanations of the operations of 
Various Kinds of Valves, Valve Motions, and Link Motions, etc., 
thereby Enabling the Ordinary Engineer to clearly Understand the 
Principles Involved in their Construction and Use, and to Plot out 
their Movements upon the Drawing Board. By Joshua Rose. M. E. 
Illustrated by 422 engravings. Revised. 358 pp. . . #6.00 

ROSE.— Steam Boilers: 
A Practical Treatise on Boiler Construction and Examination, for the 
Use of Practical Boiler Makers, Boiler Users, and Inspectors; and 
embracing in plain figures all the calculations necessary in Designing 
or Classifying Steam Boilers. By Joshua Rose, M. E. Illustrated 
by 73 engravings. 250 pages. 8vo. . . . #2.50 

3CHRIBER— The Complete Carriage and Wagon Painter: 
A Concise Compendium of the Art of Painting Carriages, Wagons, 
and Sleighs, embracing Full Directions in all the Various Branches, 
including Lettering, Scrolling, Ornamenting, Striping, Varnishing, 
and Coloring, with numerous Recipes for Mixing Colors. 73 Illus- 
trations. 177 pp. i2mo $i.ort 

DEC 16 1903