A Practical Manual of Minerals, Mines, and Mining ... Second edition ... enlarged

Front matter

A PRACTICAL MANUAL OF MINERALS, MINES, AND MINING. A PRACTICAL MANUAL OF MINERALS, MINES, AND MINING: COMPRISING SUGGESTIONS AS TO THE LOCALITIES AND ASSOCIATIONS OF ALL THE USEFUL MINERALS, FULL DESCRIPTIONS OF THE MOST EFFECTIVE METHODS FOR BOTH THE QUALITATIVE AND QUANTITATIVE ANALYSES OF EACH OF THESE MINERALS, AND HINTS UPON THE VARIOUS OPERATIONS OF MINING, INCLUDING ARCHITECTURE AND CONSTRUCTION. BY Prof. H. S. OSBORN, LL.D., AUTHOK OF " THE METALLUROY OF IRON AND STERL." AND " THE PROSPECTOR'S FIELD-BOOK AND GUIDE. ILLUSTRATED BY ONE HUNDRED AND SEVENTY-ONE ENGRAVINGS. SECOND EDITION, REVISED AND ENLARGED. PHILADELPHIA : HENRY CAREY BAIRD & CO., INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTERS, 810 WALNUT STREET. LONDON: E. & F. N. SPON, 125 STRAND. 1895. COPY'EIGHT BY' HENRY CAREY BAIRD & CO., 1895. Printed at the WICKERSHAM PRINTING HOUSE, 53 and 55 North Queen Street, Lancaster, Pa., U. 8. A. PUBLISHER'S

Preface

TO THE SECOND EDITION. The death of Dr. Osborn, more than a year ago, has caused to be devolved upon the Publisher the duty of preparing the preface to this revised edition of his Minerals, Mines and Mining. About a year before his death, Professor Osborn revised a copy of the book and placed it in the hands of the publishers for use when a new edition might be called for. The un avoidable delay in its publication has made it necessary that the statistics should be brought Lip to date, and this has been carefully done, together with an elaboration of the divisions, Nickel, Manganese and Aluminium, by a thoroughly com petent editor, under the personal supervision of the publisher ; both editor and publisher giving their best time and attention to the passage of the volume through the press.

They have earnestly aimed to do entire justice to the late eminent author, although it i.s hardly to be expected that the work has been so well done as if he, with his profound knowledge of the subjects treated, had been alive to direct it for himself, and in his own way. Henry Stafford Osborn was born in Philadelphia, August 17, 1823, and died in New York City, February 2, 1894. He was graduated at the University of Pennsylvania in 1841, and at the Union Theological Seminary, New York, in 1846. He studied at Bonn, German}*, and at the Polytechnic Institution of London, having gone abroad in 1843 or 1844. Before the publisher's preface. VI Civil war he held the chair of natural science in Roanoke College, Va., and in 1866 accepted a professorship in Lafay ette College. Leaving Lafayette in 1870, he became, in 1871, professor in Miami University, at Oxford, Ohio, where he remained until that institution was closed in 1873.

In 1865 he received, from Lafayette College, the degree of LL.D. In 1869 he published " The Metallurgy of Iron and Steel, Theoretical and Practical," an Svo. volume of nearly 1,000 pages, the success of which was immediate and pronounced. In 1888 appeared the first edition of " A Practical Manual of Minerals, Mines, and Mining," and in 1892, " The Prospec tor's Field Book and Guide." All of these books have proved acceptable to those for whom they were especially prepared, and have found a ready market. The health of Dr. Osborn having failed while he was the pastor of a church in Millville, Ohio, he determined to devote his attention to literary and scientific pursuits and to travel ; and, in 1858, he spent much time in visiting and making surveys of famous localities in Syria, Palestine, Egypt, and the islands of the Mediterranean.

These travels and re searches resulted in the publication of numerous maps and books, illustrative of those countries. Personally Dr. Osborn was earnest, enthusiastic, interesting, amiable, intensely thorough and pre-eminently just. The friendship between him and his publisher commenced in 1868, and remained unbroken, even for a single hour, up to the end of his useful and blameless life ; and this friendship will always remain among the brightest and best recollections in the long career of the undersigned as a publisher. Henry Carey Baird. Philadelphia, July 25, 1895.

PREFACE.

TO THE FIRST EDITION. The object of this manual is to place before the practical mineralogist and miner all the important help which may be derived from the present state of knowledge as it bears upon the departments of useful mineralogy, mining, and mines. We have intended to make use of the best results, not only of experiment, but of successful work, and, therefore, only the best methods have been, in most cases, presented. Neverthe less, it frequently happens that a method adopted in one con dition, or under certain circumstances, must be modified under other conditions, and there may be sound reasons for adopting another method to attain the same result. Hence, where it is difficult to pronounce upon one method, we have given an alternative. In chemical analyses and reductions, especially in the methods of detection or determination, we have confined our selves to that method which was simplest in treatment.

In practical and most technical work much depends upon the manipulation — indeed, more depends upon the neatness and the judgment of the chemist than upon his method or the process he has adopted. This work is divided into two principal parts and one sub ordinate. The first part treats of the useful minerals — their physical properties, geologic positions, local occurrence, and associations ; their methods of chemical analysis when we

PREFACE.

. wish to determine their natures and richness ; their furnace or dry assay ; and their probable present commercial values and uses ; together with such cautions which long experience has proved that the miner and practical mineralogist should observe in his researches. The second part describes the various methods of excavating and of timbering. It includes all brick and masonry work during driving, lining, bracing, and other operations included in general or special mining archi tectural work. Following Part II., the practical work of digging and boring artesian and other deep wells is fully described, with notices of the tools used and how to provide for the accidents and difficulties sometimes met with in these operations. Oxford, Ohio, December 15. 1887. CONTENTS.

Part I. Mining Mineralogy, And Economic Treatment And History Of The Useful

MINERALS. MINING MINERALOGY. PRELIMINARY PRINCIPLES AND PREPARATIONS. PAGE Requirements for the successful study of mining mineralogy and for a correct recognition of minerals .......... 1 Systems of crystallization ; Examples of crystallization ..... 2 Definition of crystallization ; Illustration of the importance of an acquaintance with the principles of crystallization ....... 3 Definition of hardness and of cleavage ........ 4 Definition of fracture and of streak ; Definition of specific gravity and method for its determination ........... 5 Rule for finding the specific gravity ; Skill in determining the specific gravities minerals acquired by practice ........ 6 Method for determining the bulk or volume of the hand .... V Precautions when great accuracy is required in determining the specificgravity ............. 8 Experiment illustrating the variations in the specific gravity at different temperatures ............. 9 Method of weighing a block of stone, marble, etc., without scales . . .10 The blow-pipe and the philosophy upon which its action depends: Unnecessary complications of the blow-pipe ; Preparation of charcoal for blow-pipe use H Sources of heat for blow-pipe practice ; Constitution of the flame of a candle. or of gas, or of an oil lamp ; Oxidizing flame . . . . . .12 Reducing flame and mode of producing it; Production of the oxidizing flame 13 Materials for blow-pipe practice; Common sal-soda; Borax; Platinum wire; Microcosmic salt ; Hard glass tubing 1-4 Preparatory practice with the blow-pipe and hints for the same : Trouble X CONTENTS.

PAGE from saliva; Avoidance of too large a bead ; Method of learning the art of blowing .......•■••■■ I5 Hints for practice with the blow-pipe ; Experiment with common litharge ; The lead orange color ; Experiments with metallic zinc and tin . 1& Water of crystallization ; Burning or oxidizing of organic matter ; Characteristic color of manganese ; Changes in the color of the bead by heating in the inner and in the outer flames ........

I* Removal of the bead ; Use of lenses ; Caution in the reduction of a metal . 18 Magnetism as a help in determining minerals ; Cupellation ; Tbe cupel and its use .19 The muffle; Preparation of a cylindrical sheet-iron stove as a substitute for a clay furnace ; Manipulation of a very small assay with the blow-pipe ; In review ...........••" 20 Importance of actual experiment ; Scales for specific gravity; Study of crystal forms from actual specimens ; The elements ...... 21 The most important fact connected with the elements ; Unchangeable combining number or " atomic weight" of the elements ; Abbreviations of the names of elements by symbols . 22 Table of combining weights of elementary bodies ...... 23 Note on the table ; Practical use of the table of atomic weights ; Method of computing the sought elements from the found . . . . . .24 Groups of compounds ........... 2ff Characteristics of the various groups of metallic oxides . . . .27 The reagents ; Water ; Alcohol 28- Hydrogen : Chlorine and method of preparing it, illustrated . . . .29 Use of chlorine as a gas .......... 30 Bromine and iodine; Forms in which bromine is used ... . . 31 Preparation of bromine ; Oxygen and its preparation . . . . .32" Iron ; Zinc ; Tin ; Hydrochloric acid ........ 33 Nitric acid ; Aquaregia; Sulphuric acid ....... 34 Hydrosulphuric acid gas or sulphuretted hydrogen, or dihydrio sulphide and its formation ............ 35 Acetic acid ; Oxalic acid ; Succinic acid ; Tartaric acid . . . .36- Sulphurous acid or anhydride ; Carbonic dioxide or carbonic acid gas ; Molybdic acid ; Potassa 37 Soda; Ammonia; Lime-water; Alumina; Litharge; Oxide of copper . . 38 Nitrate of potassium ; Sulphate of potassium ; Carbonate of potassium ; Black flux ; Chlorate of potassium ; Permanganate of potassium . . . .39' Formation of potassium permanganate ; Sulphocyanide of potassium . . 40- Potassium cyanide ; Chloride of sodium ; Sulphuret of sodium or sodium sulphide ; Sulphite of sodium ; Carbonate of sodium . . . . .41 Borax ; Phosphate of sodium ; Acetate of sodium ; Succinate of sodium ; Nitro-prusside of sodium ... 42^ Chloride of ammonium; Hydrosulphide of ammonium; Molybdate of ammonium; Acetate ot ammonium ; Oxalate of ammonium; Neutral succinate of ammonium ............

CONTENTS. XI PAGE Chloride of barium ; Nitrate of barium ; Carbonate of barium ; Chloride of calcium ............. 44 Sulphate of magnesium; Nitrate of silver; Convenient method of making pure nitrate of silver in crystals ......... 45 Litmus paper ; Red litmus paper ......... 46 Turmeric paper ; Salt of lead paper ; Microcosmic salt ; Cautions and suggestions ; Selection of a room for a laboratory and arrangement of the latter; Preparation of a sand-bath ........ 47 Arrangement of an assay furnace, described and illustrated . . . .48 Analytical scales for quantitative analyses ; Mode of weighing ; Burning filter papers 50 How to use reagents and glassware ........ 51 Meaning of using reagents " in excess ;" Caution in using reagents ; Stirring rods ; Heating glassware .......... 52 Heating flasks and beaker glasses containing solutions ; Water for assay purposes 53 List of usual chemical apparatus ......... 54 List of chemicals ; Chemicals which may be bought or made in the laboratory ; Alcoholic lamp, stand for evaporating dishes, test-tube holders, etc. 55 Folding filter papers ; Inverted cone of platinum foil and how to fit it . . 56 Apparatus for rapid filtering ; Vacuum for rapid filtering, described and illustrated 57 Platinum crucibles 59 Definition of brasque ; Fuming nitric acid, its use and preparation . . 60 Preparation of the residue in the retort from the formation of fuming nitric acid as a flux for very stubborn ores ; Sodium disulphate, its use and preparation 61 ECONOMIC TREATMENT AND HISTORY OF THE USEFUL MINERALS.

Introductory remarks ; Determination of the hardness of a mineral and list of substances by comparison with which the scale of descent, in degree may be formed 63 GOLD. Occurrent condition and form in nature ; Native . . . . . .64 Hardness and specific gravity ; Color ; Composition ; United States localities 65 Production of gold, from 1880 to 1892, in North Carolina, South Carolina and Georgia; Decline in the production of gold 68 Production of gold in the United States from 1884 to 1893 ; Alaska as a gold producing country 69 Production of gold in Alaska from 1880 to 1893 ; Extent of the mineral belt thus far developed in Alaska CONTENTS. PAGE Value of the annual output of gold and silver in the United States ; The world's production of gold ; Geology of gold and its associations ; Views in regard to the form in which gold exists in nature . . ■ • . 1 0 Gold sulphides ; Extensive distribution of gold in small quantities ; Occurrence of gold in various localities ......-• 72 Where the gold of the world has been mostly gathered ; Occurrence of gold in rocks of various ages; Gold-bearing strata of North Carolina . . 73 Manner of occurrence of gold in King's Mountain mine, of Gaston Co., N. C; The most valuable gold deposits in North Carolina . . . . .74 Peculiarity in the North Carolina gravel beds ; Average fineness of California native gold ; Remarks of Wm. E. Du Bois on native gold; Diversity in the fineness of California gold ; Fineness of gold-silver alloy . . . .75 Absurdity of a union of gold and silver in atomic proportions as asserted by eminent chemists.

Fineness of North Carolina gold; Differences in the gold of Australia ........... 76 Classification of Australian mines ; Gold of Colorado and Montana ; Natural alloys and accompaniments of gold ; Experiments by Mr. J. R. Eckfeldt in alloying gold with copper and silver ; Curious facts in gold affinities and alloys 77 Methods of treating gold alloys ; Refining gold in the Mint of the United States 78 Manner of freeing extracted gold from platinum ; Best admixture for smelting 79 Amount of gold grains in the slag ......... 80 Method of extracting gold and platinum from the slag recommended by Pettenkofer ; Melting California gold containing osmindium at the mints in Philadelphia and New York 81 Melting of gold containing osm-iridium from Bogoslowk at the mint in St. Petersburg ; Manipulation of the dross resulting from the treatment of Californian and Australian gold; Best means of separation according to d'Hennin 82 Use of cast iron in " parting " gold ; The use of platinum vessels for this purpose ; Platinum vessels at the mint in Munich ...... 83 Method of parting gold employed at the mint in Munich . . . .84 Former use of platinum vessels at St. Petersburg ; The discovery of and proving gold ores; "An eye for color" one of the most important and useful accomplishments for gold exploitation ; Simplest instrument for the discovery of gold ............ 85 The cradle or rocker, illustrated and described 86 Sluice system of washing dirt with mercury ; Wurtz's process of amalgamation g7 Crookes's amalgam ; Poorer ores containing gold ...... 88 Analysis of such ores ; Concentration of the ore . . . . . .89 The Hungarian process ; Cupellation of the gold-lead ; Treatment of the "button" ........... .90 Precautions in the treatment of gold ; Test of nitric acid for chlorine ; Defini- CONTENTS.

XIII PAGE tion of quartation ; Precaution in using crucibles in melting gold and other metals 91 Manner of using nitric acid .......... 92 SILVER. Occurrent form or appearance of silver in nature ; Hardness; Specific gravity 92 Color of silver ; Ductility ; Composition ; Localities, Geology and associations 93 Kongsberg silver mine, Norway ; Examples of very large masses of silver . 94 Occurrence of native silver ; Frequent deception caused by a mineral called arsenical iron or mispickel ; Occurrence of silver in lead ores and copper ores .............. 95 Ores indicating the neighborhood of true silver ores; Antimonial silver or dyscracite ; Bismuth silver ; Freieslebenite ; Stephanite . . . .96 Argentite ; Ruby silver or pyrargyrite ; Methods of separating the silver from associated minerals ; The dry way ; Cupellation ; Process as described by Makins 97 Preliminary assay as advised by Mitchell 98 Scorification-process ........... 99 Cupellation-process ; Objectionable feature in some otherwise very well arranged cupel furnaces . . . . . . . . . .101 Caution to be observed in the dry process ; Wet process or humid assay of silver; Haidlen and Fresenius' process of separating silver from copper . 102 Another method where gold is in association ; Caution to be observed in the wet process ; Solution of traces of silver in chlorides of potassium, sodium and ammonium ............ 103 Separation of silver from lead and from cadmium and bismuth compounds . 104 Separation of silver from mercury and from sulphurets ; The world's product of silver; Principal silver producing regions ...... 105 COPPER.

Classification of useful copper minerals ; Native copper and its occurrence in the United States ; Hardness and specific gravity ; Behavior before the blow-pipe ; Geological position ......... 106 Copper of the Lake Superior region ; Montana copper ores : Arizona copper ores .......-•■•••• 10' Copper pyrites ; Purple ore or variegated ore ; Indigo copper ; Blow-pipe and other detection of copper 108 Detection of copper in exceedingly weak solutions ; The dry method of assaying copper . . . . ■ ■ • • • • • .109 The wet method ; Caution to be observed ; Decomposition of, and separation of sulphur from copper sulphides 110 Caution to be observed in the preceding process ; Testing the liquor for nitric acid and chlorine . . . . . • ■ • • ■ .111 Oxidation of the sulphur with chlorine CONTENTS. PAGE Method of finding the amount of pure copper in the assay ; The world's production of copper in 1892 ; Total production of copper in the United States from 1840 to 1890 113 NICKEL.

Properties of nickel ; Behavior before the blow-pipe; Nickel glance or Gersdorffite • 114 Speiss ; Oxides of nickel analogous to iron, and manner of their preparation ; Chloride and sulphides of nickel ........ 115 Alloys of nickel ; Nickel and steel alloy ; Armor-plate tests made by the United States government .......... 116 Tests of nickel-steel made by Carnegie, Phipps & Co., Pittsburg, for the U. S. Navy Department ; Estimation of nickel ; Separation of constituents in a nickel ore . . . . . . . . . . . . .117 Deville's method of obtaining pure nickel ; Discovery of nickel in New Caledonia, and the form in which it is met with ; Distribution of the nickel districts 118 Copper-nickel at Gap Mine, Lancaster county, Pennsylvania ; Deposits of silicate of nickel at Riddles, Douglas county, Oregon ; Silicate of nickel in the Webster mine, North Carolina; Mr. Diller on this subject . . 119 Comparison of a series of New Caledonia silicate minerals with those of Webster, N. C, and Riddles, Oregon by F. W. Clarke; Arsenides and sulpho-arsenides in the United States; Deposits of nickel-sulphide ores at Sudbury, Canada . . 120 Analyses of an average month's output of three of the Sudbury mines ; Division of values found in screening the "Evans" mine ore; Sorting and roasting the ore ............ 121 New Process of Ludwig Mond for the reduction of nickel ores . . . 122 Foreign localities of nickel ores ......... 124 Decrease in the price of nickel ; Vessels lined or plated with nickel for culinary purposes; Crucibles of nickel; Consumption of nickel in the United States 125 Nickel product of the United States 126 IRON.

Properties of iron ; True ores of iron ; Chief ores in Great Britain ; Chief ores of iron ; Magnetic ores or magnetite 126 Properties of magnetic ores ; Associations of magnetic ores ; Effect of sulphur and phosphorus ou iron ■.......•. 127 Geologic position of magnetite; Chemical composition of magnetic ore; Hematite or red hematite 128 Influence of the magnet on hematite ; Brown hematite or limonile . . 129 Geologic position of brown hematite ; Peculiarities of appearance in the limonile in some mines ......... CONTENTS.

XV PAGE Kidney ore: Spathic ore; Black band iron ore; Chief sources of iron in the United States 131 Behavior of iron ores before the blow-pipe; Dry assay of iron ; Caution to be observed ............. 132 Treatment of ores containing sulphides, arsenides, or selenium ; Choosing samples for experiments from the ore bed ....... 134 Various methods of fluxing ; The wet method 135 Determination of phosphorus 139 Parry's method of determining phosphorus 140 Formula for deducing the pure iron ; Precipitation of lime and magnesia . 142 Cautions to be observed ........... 143 Determination of sulphur ' ....... 144 Caution to be observed ........... 145 Determination of manganese .......... 146 Determination of carbonic dioxide; Kipp's apparatus described and illustrated 149 Use of Kipp's carbonic dioxide apparatus . 150 Titanic acid and its occurrence in iron sand ; Rutile ..... 151 Detection of titanic acid under the blow-pipe ; Extraction of titanic acid from iron sand, or titanic iron ore ......... 152 Volumetric determination ; Explanatory remarks ; Volumetric determination by potassium permanganate ......... 153 The preparation used ; Preparation of the test iron ..... 154 Exhaustion of iron-ore deposits ; Remarks of Major John W. Powell on this subject; Increase in the production of pig iron ...... 159 The Gogebic district in the vicinity of Gogebic Lake, Ontonagon Co., Michigan ; Tendency towards giving attention to neglected deposits . . . 160 TIN.

Properties of pure tin ; Occurrent form of tin ; Tin-stone or cassiterite; Bell-metal ore or stannite ........... 161 Stream-tin and its occurrence in the island of Banca; Localities and Geology of tin 162 Tin-ore in Dakota ; Geological surroundings of the Black Hills ; Staurolite ; Constitution of the rock in which the tin-ore occurs ..... 163 General average content of block tin in Cornwall and Dakota ores ; Tin stone in the Black Hills, Wyoming; Wood-tin from Montana; Analysis by Dr. F. A. Genth of an ore from California; The Temescal tin mines at Cajalca ; Mineralogical appearance of tin ores . . . . . . . .164 Behavior of cassiterite before the blow-pipe ....... 165 Behavior of stannite before tbe blow-pipe ; Geology of stannite ; Extraction for detection . . . . . . . . ■ ■ .166 Estimation of the quantity of tin in any compound ..... 167 Determination of lead, if present ......... 168 Output of tin in 1891 '.

CONTENTS. ZINC. PAGE Occurrent form of zinc ; Properties of metallic zinc ; Impurities of metallic zinc • 169 Localities of zinc ores ; Occurrence of zinc sulphide ; Silicate of zinc or Willeraite ; Carbonate of zinc or Smithsonite 17° Zinc sulphide or blende ; Behavior of zinc ores under the blowpipe . . 171 Distilling zinc; Apparatus for distilling zinc on a small scale, described and illustrated 1>!2 Distilling of calamine or blende in the large way by the English method . 173 The Belgian process ; The Silesian process 174 Manufacture of the retorts, adapters, etc., employed in the Belgian process ; Mixture for the lower retorts employed at Altenberg near Aix-la-Cbapelle. 175 Various methods of manufacturing retorts ; Preparation of the clay used for the manufacture of muffles for the Silesian process 176 Construction of the muffles ; Oxide of zinc and its properties ; Proportion of metallic zinc in the oxide of zinc ........ 177 Pure metallic zinc and its preparation by the wet process .... 178 Separation of cadmium and arsenic, as well as other metallic oxides, in the analysis of zinc ore . . . . . ■ . ■ . ■ .179 Arsenious sulphide, its properties and composition ..... 181 LEAD.

Properties of lead ............ 181 Galena or galenite; Geological horizons and occurrence of lead; Production of lead in the United States 182 Galenas without silver; Gold in lead ores; Working on the large scale; Determination of the amount of lead present by the iron method . . . 183 The dry assay . ........... 184 Conversion of the lead into the sulphate in the wet method ; Composition of lead sulphate ; Picking over and sorting the lead ores .... 185 Conversion of lead sulphide into lead oxide and sulphate ; Constitution of the fumes or gaseous constituents passing off from lead ores ; Use of blowers or exhausters 186 Experiments with the Sturtevant blower; The Root blower; Pattinson's process of desilverizing lead .......... 187 Parkes's process of desilverizing lead ........ 188 Lead characteristics ; Action of water upon lead . . . . . .189 Wet assays and methods of detection ; Quantitative determination of lead. 190 Analysis of silver lead ; Mascazzinie's method of assaying lead ore . . 191 MANGANESE.

Distribution of manganese ; Foreign substances in manganese ; Separation of oxide of manganese in preparing chlorine ....... 192 Manganese ores ; Pyrolusite . . . . . . . . . .193 Braunite ; Hausmannite ; Manganite CONTENTS. XVII PAGE Varvicite ; Psilomelane 195 Average composition of 19 psilomelanes from various localities; Wad; Other useful compounds of manganese ; Manganese spar ..... 196 Rodochrosite and diallogite ; Franklinite ; Knebelite ; Behavior of compounds containing manganese before the blow-pipe ...... 197 Most important mines of manganese in the United States .... 198 Method adopted by the American Manganese Company, Limited, for sinking shafts and washing the ore at the Crimora mine, Augusta county, Va. . 199 Use of manganese ores ........... 200 Manganiferous coke for the production of crude iron ; Occurrence of manganese in the argentiferous iron ores of the upper workings of the Leadville deposits ; Use of low-grade manganese ores rich in iron, for the preparation of spiegeleisen, ferro-manganese, etc.; Chilian manganese ores; Countries producing manganese ores .......... 202 Manner of obtaining metallic manganese : Manganese alloys ; Determination of the presence of the oxide of manganese in building stones . . . 203 Process for the detection of minute traces of manganese .... 204 PLATINUM.

Properties of platinum; Geology and occurrence ...... 204 United States localities ; Analysis of California ore ..... 205 Osmiridium (iridosmine); Production of platinum in the United States; Wet process of analysis . . . . . . . . . . 206 IRIDIUM. Properties of iridium ; Table exhibiting a general view of the analytical process by which the remarkable ores associated in the ores of platinum may ' be separated from each other 209 Geographical distribution of iridium ; Occurrence in the United States . . 210 Iridium a source of great annoyance when mixed with gold dust : Separation of the metals in the mints ; Melting of iridium made possible by the discovery of Mr. John Holland, of Cincinnati 211 Use of natural grains of iridosmine for pointing gold pens ; Other uses of this metal ; Prices of iridosmine 212 MERCURY.

Occurrent forms and properties of mercury 212 Localities ; Geology aud associations 213 Chemical characteristics ; Oxides of mercury 214 Ores of mercury; Cinnabar and its properties; Preparation ot the ore; Grama or coarse ore ; Waste or lerrero ....... 215 The retort process ; Roasting in cylinder furnaces of the Rumford pattern ; The Hiittner & Scott shelf furnace 216 Process in the old intermittent furnaces ; Model of the old Rumford lime-kiln improved by Exeli ; Characteristics of mercurial compounds . . .218 Method for determining mercury in compounds CONTENTS. XVIII ANTIMONY. PAGE Properties of antimony ; Chief ores of antimony ; Stibnite ; Valentinite or white antimony; Red antimony or kermesite ; Occurrent forms of stibnite; Behavior before the blow-pipe .....•••• 221 Occurrence of antimony in the United States ; Association of antimony with cinnabar; Remarkable deposits of stibnite in Utah ..... 222 Extraction of antimony from its ores; Uses of antimony : Estimation of antimony .........••••• 223 Composition of antimony tetroxide ; To distinguish antimony from bismuth ; Makins's method of estimating antimony ....-•■ 224 Caution to be observed in making the test ....... 225 BISMUTH.

Properties of bismuth ; Artificial formation of bismuth crystals . . . 225 Detection of bismuth ; Behavior of a salt of bismuth under the blow-pipe . 226 Occurrence of bismuth in the United States: Uses of metallic bismuth . . 227 CHROMIUM. Chrome-iron or iron-stone .......... 227 Chromite and its properties: Behavior of chromite before the blow-pipe; Occurrence of chromite ; Treatment of the ore ...... 228 Deposits of chrome ore recently found : Quantitative analysis of chrome iron ore 229 COBALT. Ores of cobalt : Cobalt glance : Smaltine : Zaffre : Preparation of metallic cobalt 230 Properties of cobalt ; Occurrence of cobalt minerals in the United States ; Use of cobalt 231 Metallic value of cobalt ; Detection of cobalt compounds under the blowpipe ; Separation of cobalt from nickel ....... 232 ALUMINIUM.

Properties of aluminium .......... 233 Conductivity of heat of aluminium compared with that of other metals ; Electric conductivity of aluminium ........ 234 Efforts of St. Claire Deville to develop the aluminium industry; Development of electro-metallurgy largely due to the attempts to produce aluminium economically ; Ores of aluminium : Cryolite ; Bauxite .... 235 European and American occurrences of bauxite: Mining of bauxite iu Alabama .............. 236 Account by Mr. J. W. Spencer of the occurrence of bauxite in Georgia . . 237 Arkansas bauxites ; Analysis of bauxite from Baux ..... 238 Analyses of German bauxite : Analyses of Alabama bauxite . . . CONTENTS. XIX PAGE Analyses of Georgia bauxite ; Analyses of bauxite from Pulaski county, Arkansas ; The desired element in bauxite ....... 240 Treatment of Georgia and Alabama bauxite ; Analysis of bauxite as carried out in the Pittsburgh Testing Laboratory, Limited 241 Determination of silica and of titanic acid ....... 242 Cost of pure bauxite ore in Pittsburgh : Diaspore ; Gibbsite .... 243 Aluminite; Method of reduction ; Early processes for producing aluminium by the aid of the electric current ; M. Adolph Minet's process . . . 244 Charles M. Hall's process of manufacture of aluminium as conducted by the Pittsburgh Reduction Company ......... 245 Daily output of aluminium by the Pittsburgh Reduction Company; Alloys of aluminium ; Product of aluminium in the United States from 1883 to 1892. 248 The world's product of aluminium up to the beginning of 1893 . . 249 CORUNDUM AND EMERY.