LIBRARY UNIVERSITY OF CALIFORNIA. Class -' : .:\.-. : >: ""-V"-- - m WORKS OF Dr. GEORGE P. MERRILL PUBLISHED BY JOHN WILEY & SONS. Stone* for Building and Decoration. Third Edition, Revised and Enlarged. 8vo, x 4- 557 pages, one double-page and 32 full-page plates, and 24 figures in text. Cloth, $5.00. The Non-metallic Minerals. Their Occurrence and Uses. 8vo, xi-f4'4 pages, 32 full-page plates, mostly half-tones, and 28 figures in the text. Cloth, $4.00. PLATE I. Views in Graphite Mine near Hague, Warren County, New York. [U. S. National Museum.] THE NON-METALLIC MINERALS. THEIR OCCURRENCE AND USES. BY GEORGE P. MERRILL, Head Curator cf Geology in the 17. S. National Museum, and Professor of Geology in the Corcoran Scientific School of Columbian University^ Washington, D. C.; Author of " Stones for Building and Decoration" ''''Rocks, Rock-weathering, and Soils,' 1 '' etc. FIRST EDITION. FIRST THOUSAND. NEW YORK : JOHN WILEY & SONS. LONDON: CHAPMAN & HALL, LIMITED. 1905 fll Copyright, 1904, BY GEORGE P. MERRILL ROBERT DRUMMOND, PRINTER, NHW YORK. PREFATORY NOTE. THE work herewith presented is founded upon the author's Guide to the Study of the Collections in the Section of Applied Geology, as issued in the Report of the U. S. National Museum for 1899. The purport of the volume is merely to bring together the widely scattered notes and references relative to the occur- rences and uses of sundry minerals of value other than as ores of metals. iii 1 54693 TABLE OF CONTENTS AND SCHEME OF CLASSIFICATION. I. Elements: PAGE 1. Carbon i Diamond i Graphite 4 2. Sulphur 12 3. Arsenic 21 4. Allemontite . 22 II. Sulphides and arsenides: 1. Realgar and Orpiment; auripigment 22 2. Cobalt minerals 24 Cobaltite 24 Smaltite 26 Skutterudite v 26 Glaucodot 27 Linnaeite 27 Sychnodymite 27 Erythrite or cobalt bloom 28 Asbolite 28 3. Arsenopyrite; mispickel or arsenical pyrites 30 4. Lollingite; leucopyrite 30 5. Pyrites 31 6. Molybdenite 37 HI. Halides: 1. Halite; sodium chloride; or common salt 38 2. Fluorite 60 3. Croylite 61 IV. Oxides: i . Silica 63 Quartz 63 Flint 64 Buhrstone 65 Tripoli 65 Diatomaceous earth 66 vi TABLE OF CONTENTS AND SCHEME OF CLASSIFICATION. PAGE 2. Corundum and emery 69 3. Bauxite 86 4. Diaspore 99 5. Gibbsite; hydrargillite 100 6. Ocher; mineral paint 100 7. Ilmenite; menaccanite; or titanic iron 108 8. Rutile 109 9. Chromite ; chrome iron ore no 10- Manganese oxides 119 Franklinite 120 Hausmannite 120 Braunite 120 Polianite 121 Pyrolusite 121 Manganite -* 121 Psilomelane 121 Wad or bog manganese 122 ii. Mineral waters 128 V. Carbonates: 1. Calcium carbonate f 132 Calcite; calc spar; Iceland spar 132 Chalk 137 Limestones; mortars; and cements 139 Portland cement 142 Roman cement 144 Playing marbles 146 Lithographic limestones 146 2. Dolomite 151 3. Magnesite 152 4. Witherite 157 5. Strontianite. . . .' 158 6. Rhodochrosite; diallogite 159 7. Natron 159 8. Trona; urao 160 vVI. Silicates: 1. Feldspars 160 2. Micas 163 3. Asbestos 180 4. Garnet 193 5. Zircon 195 6. Spodumene and petalite 196 7. Lazurite; lapis lazuli; native ultramarine 198 8. Allanite; orthite 200 9. Gadolinite 201 10. Cerite 203 11. Rhodonite - 204 12. Steatite; talc; and soapstone 204 TABLE OF CONTENTS AND SCHEME OF CLASSIFICATION. vii PAGE 13. Pyrophyllite; agalmatolite; and pagodite 214 14. Sepiolite; meerschaum 215 15. Clays 217 16. Fuller' s-earth 248 VII. Niobates, tantalates, and tungstates: 1 . Columbite and tantalite 251 2. Yttrotantalite 251 3. Samarskite 252 4. Wolframite and Hiibnerite 253 5. Scheelite 257 VIII. Phosphates and vanadates: 1. Apatite; rock phosphates; guano, etc .- 260 2. Monazite 293 3. Vanadinite 299 4. Descloizite 300 5 . Amblygonite 304 6. Triphylite and lithiophilite 305 IX. Nitrates: 1 . Niter, potassium nitrate 306 2. Soda niter 307 3. Nitro-calcite 310 X. Borates: 1. Borax or tincal; borate of soda 313 2. Ulexite; boronatrocalcite 313 3. Colemanite 313 4. Boracite or stassfurtite; borate of magnesia 313 XI. Uranates: 1 . Uraninite; pitchblende 320 2. Carnotite 322 XII. Sulphates: 1. Barite; heavy spar 324 2. Gypsum 326 3. Celestite 332 4. Mirabilite; Glauber salt 333 5. Glauberite 336 6. Thenardite 336 7. Epsomite; epsom salts 337 8. Polyhalite 338 9. Kainite 338 10. Kieserite 338 11. Alums: Kalinite 339 Tschermigite 339 Aluminite 342 Alunite 342 Alum slate or shale 344 viii TABLE OF CONTENTS AND SCHEME OF CLASSIFICATION. XIII. Hydrocarbon compounds: PAGE 1. Coal series 346 Peat 346 Lignite or brown coal 348 Bituminous coal 349 Anthracite coal 349 2. Bitumen series 352 Marsh gas; natural gas 358 Petroleum 359 Asphaltum; mineral pitch 361 Manjak 366 Elaterite; mineral caoutchouc 367 Wurtzillite 367 Albertite 368 Grahamite 369 Carbonite or natural coke 370 Uintaite; gilsonite , 371 3. Ozokerite; mineral wax; native paraffin 373 4. Resins 377 Succinite; amber 377 Retinite 379 Chemawinite 379 Gum copal 380 XIV. Miscellaneous: 1. Grindstones; whetstones; and hones 388 2. Millstones 397 3. Pumice 398 4. Rottenstone 400 5. Madstones 401 6. Molding sand 401 7. Road-making materials 405 LIST OF ILLUSTRATIONS. PLATES. FACING PAGE I. Views in Graphite Mine, near Hague, Warren Co., N. Y. From photo- graphs by C. D. Walcott Frontispiece II. Section of Salt Beds at Stassfurt, Germany. Trans. Edinburgh Geo- logical Society, V, 1884, p. 1 1 1 50 III. Views of Brine Evaporating-tanks at Syracuse, N. Y. From photographs by I. P. Bishop 58 IV. View of Tripoli Mine at Seneca, Mo 65 V. Deposit of Diatomaceous Earth, Great Bend of Pitt River, Shasta Co., Cal. From photograph by J. S. Diller 68 VI. Big Vein between the Peridotite and Gneiss at Corundum Hill, Macon Co., N. C. After J. H. Pratt, Bull. No. 180, U. S. Geol. Survey. . . 72 VII. Views of Peridotite Outcrops and Corundum Vein at Laurel Creek, Ga. After J. H. Pratt, Bull. No. 180, U. S. Geol. Survey 74 VIII. Microstructure of Emery. After Tschermak, Min. u. Pet. Mittheilun- gen, XIV, Part IV 7,7 IX. Mass of Botryoidal Psilomelane from Crimora, Va. Specimen No. 66722, U. S. National Museum 119 X. Ideal Section to show the Origin of Manganese Deposits through the Weathering of Limestone. After R. F. Penrose, Ann. Rep. Geol. Surv. of Arkansas, I, 1890 *. 122 XI. Views showing Occurrence of Calcite in Iceland. After Thorroddsen 133 XII. View in Cement Quarry near Whitehall, Ulster Co., N. Y. From photo- graph by N. H. Darton 144 XIII. Quarry of Lithographic Limestone, Solenhofen, Bavaria. From a photo- graph 146 XIV. View showing Large Spodumene Crystals in Granitic Rock, Etta Mine* Black Hills, S. D. After E. O. Hovey, Bull. Geol. Soc. of America. . 197 XV. Soapstone Quarry, Lafayette, Penna . > . . 210 XVI. Kaolin Pit, Delaware Co., Penna 218 XVII. Views showing Appearance under the Microscope of (i) Kaolinite and (2) Washed Kaolin 224 XVIII. Views showing Appearance under the Microscope - of (i) Halloysite and (2) Glacial (Leda) Clay 226 XIX. Glarial (Leda) Clay, Lewiston, Me. From photograph by L. H. Merrill 228 ix LIST OF ILLUSTRATIONS. FACING PAGE XX. Views showing Appearance under the Microscope of (i) Clay, Albany Co , Wyo. and (2) Fullers' Earth 249 XXI. Map showing Phosphate Regions of Florida. After G. H. Eldridge . . . 272 XXII. Sections through Tennessee Phosphate Beds. After C. W. Hayes 274 XXIII. Borax Mine, near Daggett, Cal., Interior and Exterior Views. From photographs 317 XXIV. Gypsum Quarry, Fort Dodge, la. From photograph by Iowa Geo- logical Survey 329 XXV. Map showing Areas where Bitumen Occurs in the United States. From Report of Tenth Census 346 [XXVI. Map showing the Developed Coal Fields of the United States. From Report of Eleventh Census 352 XXVII. Plan of Pitch Lake, Island of Trinidad. After S. F. Peckham 361 XXVIII. Quarry of Bituminous Sandstone, Santa Cruz District, California. After G. H. Eldridge, U. S. Geol. Survey 364 XXIX. Quarry of Bituminous Sandstone, Indian Territory. After G. H. Eldridge 365 XXX. Microsections of Mica Schist used in making Hones. Fig. i, Cut across the Grain; Fig. 2, Cut parallel with Grain 388 XXXI. Novaculite Quarry, Arkansas. After Griswold, Ann. Rep. Geol. Surv. of Arkansas, III, 1890 394 XXXII. Microsections of (i)] Arkansas Novaculite and (2) Ratisbon Razor Hone. Dark Bodies in (2) are Garnets 396 FIGURES IN TEXT. PAGB 1. Diamond Crystals. After Wirt Tassin, Ann. Rep. U. S. National Museum, I93 2 2. Sulphur in Limestone, Sicily. Ann. Rep. U. S. National Museum, 1899 18 3. Halite Crystals, Stassfurt, Germany. Ibid , 40 4. Section of Petite Anse, Louisiana. After Hilgard 46 5. Sylvite Crystals, Stassfurt, Germany. Ann. Rep. U. S. National Museum, 1899 49 6. Corundum. After Wirt Tassin, Ann. Rep. U. S. National Museum, 1903. 69 7. Ideal Cross-section of a Corundum Contact at Corundum Hill Mine, N. C. After J. H. Pratt, U. S. Geol. Survey 71 8. Map of the Peridotite Formation at Corundum Hill, Macon Co., N. C. After J. H. Pratt, U. S. Geol. Survey 72 9. Map of the Buck Creek Peridotite Area, showing the Relation of the Amphi- bolite Dikes. Ibid 73 10. Map of the Peridotite Formation at Laurel Creek, Rabun Co., Ga. Ibid 74 11. Map showing Location of Emery Deposit at Chester, Mass. Ibid 81 12. Cross-section of Old Emery Mine at Chester, Mass., showing the Amount of Emery taken out prior to April, 1899. Ibid 82 13. Pisolitic Bauxite, Bartow Co., Ga. Ann. Rep. U. S. National Museum, 1899. 86 14. Map showing the Geological Relations of the Georgia and Alabama Bauxite Deposits. After C. W. Hayes 94 LIST OF ILLUSTRATIONS. xi PAGE 15. Section showing the Relation of Bauxite to Mantle of Residual Clay in Georgia. Ibid 95 16. Section across the Rutherford and Barclay Paint Mine at Lehigh Gap, Penna. After C. E. Hesse 104 17. Ground Plan of Manganese Deposits at Crimora, Va. After C. E. Hall ... 124 18. Sections through Crimora, Va., Manganese Deposit. After C. E. Hall 124 19. Sections of Mica Vein in Yancey Co., N. C. After W. C. Kerr 169 20. Asbestos Fibers. Ann. Rep. U. S. National Museum, 1899 182 21. Vein of Serpentine Asbestos in Massive Serpentine. Ann. Rep. U. S. Na- tional Museum, 1899 188 22. Outlines of Garnet Crystals 194 23. Outlines of Zircon Crystals 196 24. Vanadinite, showing Hopper-shaped Crystals 300 25. Map of Chilean Nitrate Region. After Fuchs and De Launay 309 26. Section through Sulphur Mountain and Ojai Plateau, California. After S. F. Peckham 357 27. Asphalt Vein Ten Miles East of Havana, Cuba. After R. C. Taylor 363 28. Section across Quarry of Gilsonite Paving and Roofing Co., showing Bitu- minous Limestone and Associated Strata. After G. H. Eldridge 366 OF THE UNIVERSITY OF THE NON-METALLIC MINERALS, EXCLUSIVE OF GEMS, BUILDING STONES, AND MARBLES. I. ELEMENTS. I. CARBON. THE numerous compounds of which carbon forms the chief constituent are widely variable in their physical properties and origin. As occurring in nature few of its members possess a definite chemical composition such as would constitute a true mineral species, and they must for the most part be looked upon as indefinite admixtures in which carbon, hydrogen, and oxygen play the more important roles. For present purposes the entire group may be best con- sidered under the heads of (i) The Pure Carbon series; (2) The Coal series, and (3) The Bitumen series, the distinctions being based mainly on the gradually increasing amounts of volatile hydrocarbons, a change which is accompanied by a variation in physical condition from the hardest of known minerals through plastic and liquid to gaseous forms. Here will be considered only the members of the pure carbon series, the others being discussed under the head of hydrocarbon compounds. Diamond. This mineral crystallizes in the isometric system, with a tendency toward octahedral forms, the crystals showing curved and striated surfaces. (Fig. i.) The hardness is great, 10 of Dana's scale; the specific gravity varies from 3.1 in the carbonados to 3.5 in good clear crystals. The luster is adamantine; the colors, white or colorless, through yellow, red, orange, green, blue, brown to black. The transparent and highly refractive forms are of value as gems, THE NON-METALLIC MINERALS. and can best be discussed in works upon this subject. We have i,. ^ .. to do here rather with the I rough, confused crystal- line aggregates or round- ed forms, translucent to opaque, which, though of no value as gems, are of the greatest utility in the arts. To such forms the name black diamond, bortj and carbonado are applied. Origin and occur- rence. The origin of the diamond has long FlG. i. Diamond crystals; characteristic forms. [U. S. National Museum.] been a matter of dis- cussion. A small pro- portion of the diamonds of the world are found in alluvial deposits of gravel or sand. In the South African fields they occur in a so-called blue gravel, formed, according to Lewis, along the line of contact between an eruptive rock (peridotite) and highly carbonaceous shales. They were regarded by Lewis as originating through the crystallization of the carbon of the shales by the heat of the molten rock. De Launay states, however, that there is no necessary connection between the shales and the diamond, and shows with apparent collusiveness that the latter occur often in a broken and fragmental condition, such as to indicate beyond doubt that they originated at greater depths and were brought upward as phenocrysts in the molten magma at the time of its intrusion. The primary origin of the diamonds he regards as through the crystallization, under great pressure, of the carbon contained in the basic magma in the form of metallic carbides. The diamond-bearing rock, i.e., the true parent rock, has since been shown by Bonney * to be an eclogite, i.e., an igneous rock com- posed essentially of a green amphibole, pyroxene, and garnets. 1 Geol. Magazine, Vol. VI, 1899, p. 309. ELEMENTS. 3 Whether or not a similar origin to that outlined above can be attributed to the Brazilian diamonds is as yet unproven. Their occurrence and association with detrital materials resulting from the breaking down of older rocks, with which they may or may not have been originally associated, renders the problem obscure and difficult of solution. According to Kunz, 1 95 per cent of all diamonds at present obtained come from the Kimberly Mines, Griqua Land, west South Africa; of these, some 47 per cent are bort. The remainder come from Brazil, India, and Borneo. A few have been found in North America, the Ural Mountains, and New South Wales, but these countries are not recognized as regular and constant sources of supply. Uses. The material, aside from its use as a gem, owes its chief value to its great hardness, and is used as an abrading and cutting medium in cutting diamonds and other gems, glass, and hard materials in general, such as can not be worked by softer and cheaper sub- stances. With the introduction of machinery into mining and quarrying there has arisen a constant and growing demand for black diamonds, or bort, for the cutting edges of diamond drills, and to a less extent for teeth to diamond saws. The crystallized diamond is not suitable for these purposes owing to its cleavage property. The best bort or "carbonado" comes, it is said, from Bahia, Brazil, where it is found as small, black pebbles in river gravels. The ordinary sizes used for drills weigh but from one-half to i carat, but in special cases pieces weigh- ing from 4 to 6 carats are used. It is stated that the crowns of large drills, 10 inches in diameter, armed with the best grade of carbonado, are sometimes valued as high as $10,000. BIBLIOGRAPHY. M. BABINET. The Diamond and other precious stones. Report of the Smithsonian Institution, 1870, p. 333. A. DAUBREE. Annales des Mines, yth Ser., IX, 1876, p. 130. Remarking on the occurrence of platinum associated with peridotites, he calls attention to the fact that Maskelyne had shown the diamonds of South Africa and Borneo to occur in a decomposed peridotite. 1 Gems and Precious Stones, New York, i8qo. 4 THE NON-METALLIC MINERALS. ORVILLE A. DERBY. Geology of the Diamantiferous Region of the Province of Parana, Brazil. American Journal of Science, XVIII, 1879, p. 310. Geology of the Diamond. American Journal of Science, XXIII, 1882, p. 97. R. COHEN. Igneous origin of the Diamond. Proceedings, Manchester Literary and Philosophical Society, 1884, p. 5. H. CARVILL LEWIS. The Genesis of the Diamond. Science, VIII, 1886, p. 345. GARDNER F. WILLIAMS. The Diamond Mines of South Africa. Transactions of the American Institute of Mining Engineers, XV, 1886, p. 392. ORVILLE A. DERBY. The Genesis of the Diamond. Science, IX, 1887, p. 57. Discovery of Diamonds in a Meteoric Stone. Nature, XXXVII, 1887, p. no. Diamond Mining in Ceylon. Engineering and Mining Journal, XLIX, 1890, p. 678. A. MERVYN SMITH. The Diamond Fields of India. Engineering and Mining Journal, LIII, 1892, p. 454. OLIVER WHIFFLE HUNTINGTON. Diamonds in Meteorites. Science, XX, 1892, p. 15. Diamonds in Meteoric Stones. The American Geologist, XI, 1893, p. 282. (Abstract of paper by H. Moissan, Comptes Rendus 1893, pp. 116 and 228.) HENRI MOISSAN. Study of the Diamantiferous Sands of Brazil. Engineering and Mining Journal, LXII, 1896, p. 222. HENRY CARVILL LEWIS. I. Papers and Notes on the Genesis and Matrix of the Diamond, edited by Prof. T. G. Bonney. The Geological Magazine, IV, 1897, p. 366. Sir WILLIAM CROOKES. Diamonds. Nature, LV, 1897, p. 325. L. DE LAUNAY. Les Diamants du Cap. Paris, 1897. ORVILLE A. DERBY. Brazilian Evidence on the Genesis of the Diamond. The Journal of Geology, VI, 1898, p. 121. H. W. FURMISS. Carbons in Brazil. U. S. Consular Reports, 1898, p. 604. See also Engineering and Mining Journal, LXVI, 1898, p. 608. M. J. KLINCKE. Gites Diamantiferes de la Republique sud-Africaine. Annales des Mines, XIV, 1898, p. 563. GARDNER F. WILLIAMS. The Diamond Mines of South Africa. The Macmillan Comnarv, London, TOO?. Graphite. Graphite, plumbago, or black La:1, 2.5 1: L variously cal ed, is a dark steel-gray to black lustrous mineral v;ith a black streak; hardness of but 1.2, and a specific gravity of from 2.25 to 2.27. The prevailing form of the mineral is scaly or broadly foliated, ELEMENTS. 5 with a bright luster, but it is sometimes quite massive and columnar or earthy, with a dull coal-like luster. Its most characteristic features are its softness, greasy feeling, and property of soiling everything with which it comes in contact. Molybdenite, the sulphide of molybdenum, is the only mineral with which it is likely to become confounded. This last, however, though very similar in general appearance, gives a streak with a slight greenish tinge, and when fused with soda before the blowpipe yields a sulphur reaction. Chemically, graphite is nearly pure carbon. The name black lead is therefore erroneous and misleading, but has become too firmly established to be easily eradicated. The analyses given below show the composition of some of the purest natural graphites. Locality. Carbon. Ash. Volatile Matter. Ceylon 08.817 o 280 O QO Do OO 7Q2 QC ic8 Buckingham, Canada 97 626 I 78 .i^O CQA Do . . oo 81 ? O76 oy4 . ivy As mined the material is almost invariably contaminated by mechanically admixed impurities. Thus the Canadian material as mined yields from 22.38 to 30.51 per cent of graphite; the best Bavarian, 53.80 per cent. The grade of ore that can be economi- cally worked naturally depends upon the character of the impurities and the extent and accessibility of the deposit. It is said 1 that deposits at Ticonderoga, New York, have been worked in which there was but 6 per cent of graphite. Occurrence and origin. Graphite occurs mainly in the older crystalline metamorphic rocks, both siliceous and calcareous, some- times in the form of disseminated scales, as in the crystalline lime- stone of Essex County, New York, or in embedded masses, streaks, and lumps, often of such dimensions that single blocks of several hundred pounds weight are obtainable. It is also found in the form of veins. The fact that the mineral is carbon, one of the constituents of 1 Engineering and Mining Journal, LXV, 1898, p. 256. 6 THE NON-METALLIC MINERALS. animal and vegetable life, has led many authorities to regard it, like coal, as of vegetable origin. While this view is very plausible it can not, however, be regarded as in all cases proven. That graphite may be formed independently of organic life is shown by its presence in cast iron, where it has crystallized out, on cooling, in the form of bright metallic scales. Carbon is also found in meteorites which are plainly of igneous origin, and which have thus far yielded no certain traces of either plant or animal organisms. It is, however, a well-known fact that coal itself of organic origin has in some cases been converted into graphite through metamorphic agencies, and intermediate stages like the graphitic anthracite of Newport, Rhode Island, afford good illustrations of such transitions. Certain European authorities 1 have shown that amorphous carbonaceous particles in clay slates have been converted into graphite by the metamorphosing influence of intruded igneous rocks. Prof. J. S. Newberry described an occur- rence of this nature in the coal fields of Sonora, Mexico, 2 as follows: " All the western portion of this coal field seems to be much broken by trap dikes which have everywhere metamorphosed the coal and converted it into anthracite. At the locality examined the metamorphic action has been extreme, converting most of the coal into a brilliant but somewhat friable anthracite, containing 3 or 4 per cent of volatile matter. At an outcrop of one of the beds, however, the coal was found converted into graphite, which has a laminated structure, but is unctuous to the touch and marks paper like a lead pencil. The metamorphism is much more complete than at Newport (Rhode Island), furnishing the best example yet known to me of the con- version of a bed of coal into graphite." In New York State and in Canada, graphite occurs in Laurentian rocks, both in beds and in veins, a portion of the latter being appar- ently true fissure veins and others shrinkage cracks or segregation veins which traverse in countless numbers the containing rocks. It is said 3 that in the Canadian regions the deposits occur generally in 1 Beck and Luzi, Berichte der Deutschen Chemischen Gesellschaft, 1891, p. 24. 2 School of Mines Quarterly, VIII, 1887, p. 334. 3 See On the Graphite of the Laurentian of Canada, by J. W. Dawson, Proceedings of "the Geological Society of London, XXV, 1870, p. 112, and an article on Graphite by Prof. J. F. Kemp in The Mineral Industry, II, 1893, P- 335- ELEMENTS. 7 limestone or in their immediate vicinity, and that granular varieties of the rock often contain large crystalline plates of plumbago. At other times the mineral is so finely disseminated as to give a bluish-gray color to the limestone, and the distribution of the bands thus colored seems to mark the stratification of the rock. Further, the plumbago is not confined to the limestones; large crystalline scales of it are occasionally disseminated in pyroxene rock or pyral- lolite, and sometimes in quartzite and in feldspathic rocks, or even in magnetic oxide of iron. In addition to these bedded forms, there are also true veins in which graphite occurs associated with calcite, quartz, orthoclase, or pyroxene, and either in disseminated scales, in detached masses, or in bands or layers separated from each other and from the wall rock by feldspar, pyroxene, and quartz. Kemp describes 1 the graphite deposit near Ticonderoga, New York, as in the form of a true fissure vein, cutting the lamination of the gneissic walls at nearly right angles. The wall rock is a garnetiferous gneiss, with an east and west strike, and the vein runs at the "big mine" north 12 west, and dips 55 west. The vein filling, he says, was evidently orthoclase (or microcline) with quartz and biotite and pockets of calcite. Besides graphite, it contained tourmaline, apatite, pyrite, and sphene. Walcott 2 describes the graphite at the mines 4 miles west of Hague, on Lake George, New York, as occurring in Algonkian rocks, and as probably of organic origin. " At the mines the alternating layers of graphite shale or schist form a bed varying from 3 to 13 feet in thickness. The outcrop may be traced for a mile or more. The garnetiferous sandstones form a strong ledge above and below the graphite bed. The appearance is that of a fossil coal bed, the alteration having changed the coal to graphite and the sandstone to indurated, garnetiferous, almost quartzitic sandstones. The character of the graphite bed is well shown in the accompanying plate, from a photograph taken by me in 1890. It is here a little over 9 feet in thickness and is formed of 1 Preliminary Report on the Geology of Essex County, Contributions from the Geo- logical Department of Columbia College, 1893, pp. 452, 453. 2 Bulletin of the Geological Society of America, X, 1898, p. 227. 8 THE NON-METALLIC MINERALS. alternating layers of highly graphitic sandy shale and schist." (See Plate I.) According to J. Walther * the Ceylonese graphite occurs in coarsely foliated or stalky masses in veins in gneiss which, where mined, is decomposed to the condition of laterite. The veins are regarded as true fissures, and vary from 12 to 22 cm. (about 4} to 8f inches) in width. The graphite of Northern Moravia occurs in gray to black crystalline granular Archaean limestone interbedded with amphibo- lites and muscovite gneiss, the limestone itself being often serpen- tinous, in this respect apparently resembling the graphitic portions of the ophicalcites of Essex County, New York. The material is quite impure, showing on the average but 53 per cent of carbon and 44 per cent of ash, the latter being made up largely of silica and iron oxide, with a little sulphur, magnesia, and alumina. This graphite is regarded as originating through the metamorphism of vegetable matter included in the original sediments, the agencies of metamorphism being both igneous intrusions and the heat and pressure incidental to the folding of the beds. 2 As to so much of the graphite as occurs in beds there seems, then, little doubt as to its origin from plant remains which may be imagined to have existed in the form of seaweeds or to have been de- rived from diffused bituminous matter. The origin of the vein material is not so evident, though it seems probable that it is due to the metamorphism of bituminous matter segregated into veins, like those of albertite in New Brunswick or of gilsonite, etc., in Utah. Kemp states that the Ticonderoga graphite must have reached the fissure as some volatile or liquid hydrocarbon, such as petroleum, and become metamorphosed, in time, to its present state. Walther believes the Ceylon material to have originated by the reduction of carburetted vapors. (See also under origin of diamonds, p. 2.) The total quantity of carbon in the form of graphite in the Lauren- tian rocks of Canada has been estimated by Dawson as equal to that in any similar areas of the Carboniferous system of Pennsylvania. 1 Records of the Geological Survey of India, XXIV, 1891, p. 42. * Jahrbuch k. k. Geologische Reichsanstalt, 1897, XL VII, p. 21. ELEMENTS. 9 Sources. The chief sources of the graphite of commerce are Austria and Ceylon. Other sources of commercial importance are Germany, Italy, Siberia, the United States, and Canada. The chief deposits of commercial value in the United States are at Ticonderoga, New York, where the graphite occurs in a granular quartz rock, or, according to J. F. Kemp, in "Elliptical Chimneys in Gneiss which are filled with Calcite and Graphite," and Hague, in Warren County. An earthy, impure graphite, said to be suitable for foundry facings, is mined near Newport, Rhode Island. About one hundred years ago the material was mined in Bucks County, Pennsylvania. Other American localities are: Bloomingdale, New Jersey; Clinton- ville, New York; Raleigh, Wake County, North Carolina; Lehigh and Berks counties, Pennsylvania; Salt Sulphur Springs, West Virginia; St. Johns, Tooele County, Utah. Graphite is a very common mineral in the Laurentian rocks of Canada. The most important known localities are north of the Ottawa River, in the townships of Buckingham, Lochaber, and Grenville. At Buckingham it is stated masses of graphite have been obtained weighing nearly 5,000 pounds. At Grenville the graphite occurs in a gangue consisting mainly of pyroxene, wollas- tonite, feldspar, and quartz, while the country rock is limestone. Blocks of graphite have been obtained weighing from 700 to 1,500 pounds. 1 Graphite is also found in Japan, Australia, New Zealand, Green- land, Guatemala, Germany, and in almost all the Austrian provinces; the most important and best known deposits being those of Kaiser- berg at St. Michel, where there are five parallel beds occurring in a grayish-black graphite schist, the beds varying from a few inches to 6 yards. The only workable deposit in Germany is stated to be at Passau in Bavaria. The material occurs in a feldspathic gneiss, seeming to take the place of the mica. The beds have been worked chiefly by peasants for centuries, and the output used mainly for crucibles. 2 Uses. Graphite is used in the manufacture of "lead" pencils, lubricants, stove blacking, paints, refractory crucibles, and for 1 Descriptive Catalogue of Economic Minerals of Canada, 1876, p. 122. 2 The Journal of the Iron and Steel Institute, 1890, p. 739. io THE NON-METALLIC MINERALS. foundry facings. In the manufacture of pencils only the purest and best varieties are used, and high grades only can be utilized for lubricants. For the other purposes mentioned impure materials can be made to answer. In the manufacture of the Dixon crucibles, a mixture of 50 per cent graphite, 33 per cent of clay, and 17 per cent of sand is used. Preparation.- In nature graphite is usually associated with harder and heavier materials, which it is necessary to get rid of before the 1 material is of value. In New York it is the custom to crush the rock in a battery of stamps, such as are used in gold milling, and then separate the graphite by washing, its lighter specific gravity permitting it to be floated off on water, while the heavy, injurious constituents are left behind. Mica, owing to its scaly form, can not be separated in this manner, and hence micaceous ores of the mineral are of li tie if any value. An improvement in the manufacture of plumbago or graphite has been described in a " recent patent specification. Graphite, crushed and passed through a sieve of from 120 to 150 meshes per inch, is stirred into a saturated solution of alum or aluminum sulphate at a temperature of 2i2F.; steatite is then added, and more water, if required. After mixing, excess of water is evaporated until a consistency suited to grinding in a chilled steel or other mixer is obtained. More graphite may here be added; then, after thorough grinding, the material may be compressed into cakes for household use, or is ready for the manufacture of pencils or crucibles. The aver- age formula of the mixture is: Graphite, 80 .parts; steatite, soapstone, or talc, 14 parts; alum, 6 parts; but this varies with the purpose to which the material is to be applied. When several different kinds of graphite have to be employed, the richest in carbon is first mixed into the alum solution. By this process graphites previously re- garded as incapable of being compacted are utilized, and are im- proved in polishing power. For pencils the material may be hard without being brittle, and black without being soft, \\hile crucibles made from the treated graphite are at once harder, more durable, and lighter. 1 1 Engineering and Mining Journal, LVIII, 1894, p. 440. ELEMENTS. II Prices. The value of the mineral varies with its quality. In 1899 the crude lump was reported as worth $8 a ton and the pulver- ized $30. The annual output as given 1 for the principal countries is as fol- lows: WORLD'S PRODUCTION OF GRAPHITE. Year. Austria. Canada. Ceylon. Germany. India. Italy. United States. Metric Metric Metric Metric Metric Metric Metric tons. tons. tons. tons. tons. tons. tons. 1892 20,978 151 21,300 4,036 (a) 1,645 77 1893.... 23,807 Nil. 21,900 3fi49 (a) 1,465 634 1894-..- 24,121 63 10,718 3,133 1,623 i,575 349 1895.... 28,443 199 !3,7n 3,75* (a) 2,657 171 1896.... 35,972 126 10,463 5,248 (a) 3,i48 184 l8 97 .... 3 8 >54 39 6 619,275 3,861 61 5,650 450 1898.... 33,062 1,107 678,509 4,593 22 6,435 824 l8 99 .... 31*819 1,105 29,037 5,^6 1,548 9,990 1,648 1900 33,663 *,743 9,248 1,858 9,720 1,862 a. Not reported in the Government statistics, b. Exports. - Mexico also produces some 2,500 tons yearly. Some 2,500,000 pounds of graphite are produced artificially by the International Graphite Company, at Niagara Falls, New York. BIBLIOGRAPHY. J. W. DAWSON. On the Graphite of the Laurentian of Canada. Quarterly Journal Geological Society of London, XXVI, 1870, p. 112. M. BONNEFOY. Memoire sur la Geologic et 1'Exploitation des Gites de Graphite de la Boheme Meridionale. Annales des Mines, 7th Ser., XV, 1879, p. 157. JOHN S. NEWBERRY. The Origin of Graphite. School of Mines Quarterly, VIII, 1887, p. 334. Der Graphitbergbau auf Ceylon. Berg- und Hiittenmannische Zeitung, XLVII, 1888, p. 322. J. WALTHER. Ueber Graphitgange in zersetztem Gneiss (Laterit) von Ceylon. Zeitschrift der Deutschen Geologischen Gesellschaft, XLI, 1889, p. 359. A. PALLAUSCH. Die Graphitbergbaue im siidlichen Bohmen. ' Berg- und Huttenmannisches Jahrbuch, XXXVII, 1889, p. 95. T. ANDREE. Graphite Mining in Austria and Bavaria. (Abstract.) Journal of the Iron and Steel Institute, 1890, p. 738. J. POSTLETHWAITE. The Borrowdale Plumbago; its Mode of Occurrence and Probable Origin. Proceedings of the Geological Society of London, Session, 1889-90, p. 124. On the formation of Graphite in contact-metamorphism. American Journal of Science, XLII, 1891, p. 514. Review of article in Be- richte der Deutschen Chemischen Gesellschaft, XXIV, p. 1884, 1891. !The Mineral Industry, VI, 1897; VIII, 1899. 12 THE NON-METALLIC MINERALS. W. Luzi. Zur Kenntniss des Graphitkohlenstoffes. (Berichte der Deutschen Chemischen Gesellschaft, XXiy, pp. 4085-4095. 1891.) Neues Jahrbuch fiir Mineralogie, Geologic und Paleontologie. 1893. II, Part 2, p. 241. (Abstract.) E. WEINSCHENK. Zur Kenntniss der Graphitlagerstatten. Chemisch-geologischt Studien von Dr. Ernst Weinschenk. i. Die Graphitlagerstatten des bayerischen Grenzgebirges. Habilitations- schrift zur Erlangung der venia legendi an der K. technischen Hochschule. Miinchen, 1897. FRANZ KRETSCHMER. The Graphite Deposits of Northern Moravia. Transactions of the North of England Institute of Mining and Mechanical Engineering, XLVII, 1898, p. 87. 2. SULPHUR. Color of the mineral when pure, yellow, sometimes brownish, reddish, or gray through impurities. Hardness, 1.5 to 2.5. Specific gravity, 2.05. Insoluble in water or acids. Luster resinous. Occurs native in beautiful crystals or in massive stalactitic and spheroidal forms. Once seen the mineral is as a rule readily recognized, and all possible doubts are set at rest by its ready inflammability, its burning with a faint bluish flame and giving the irritating odors of sulphurous anhydride. In nature often impure through the presence of clay and bituminous matters; sometimes contains traces of sile- nium or tellurium. Origin and mode oj occurrence. Sulphur deposits of such extent as to be of economic importance occur as a product of volcanic activity, or result from the alteration of beds of gypsum. On a smaller scale, and of interest from a purely mineralogical standpoint, are the occurrences of sulphur through the alteration of pyrite and other metallic sulphides. As a product of volcanic action sulphur is formed through the oxidation of hydrogen sulphide (H 2 S), which, together with steam and other vapors, is a common exhalation from volcanic vents and solfataras. Such deposits on a small scale may be seen incrusting fumaroles in the Roaring Mountain or associated with the sinter deposits of the Mammoth Hot Springs in the Yellowstone Park. It may also be produced through the mutual reaction of hydrogen sulphide (H 2 S) on sulphuric anhydride (SO 3 ), the product being sulphur (S) and water (H 2 O) as before. To these types belong the ELEMENTS. 13 sulphur deposits of Utah, California, Nevada, and Alaska in the United States, as well as those of Mexico, Japan, Iceland, and other volcanic regions. " Sulphur is derived from the sulphate of lime (gyp- sum or anhydrite) through the reducing action of organic matter. The sulphate, through the loss of its oxygen, becomes converted into a sulphide, which, through the carbonic acid in the air and water, becomes finally reduced to hydrogen sulphide with the formation of calcium carbonate. According to Fuchs and De Launay 1 there is formed at the same time with the hydrogen sulphide, a polysulphide, which in its turn yields a precipitate of sulphur and carbonate of lime. The maxi- mum amount of sulphur which would thus result from the decompo- sition of a given amount of gypsum is stated to be 24 per cent. This method of origin is illustrated in the celebrated deposit of Sicily, where we have the sulphur partially disseminated through and partly interbedded with a blue-gray limestone. Beneath the sulphur beds as they now exist are found the older gypseous beds, which through decomposition have yielded the materials for the lime and sulphur beds now overlying. With these Sicilian sulphurs occur a number of beautiful secondary minerals, as celestite, calcite, aragonite, and selenite. Sulphur derived directly from metallic sulphides is of little economic interest. Kemp states 2 that masses of pyrite in the cal- ciferous strata on Lake Champlain may yield crusts of sulphur an inch or so thick, and it is not uncommon to find small crystals of the mineral resulting from the alteration of galena, as described by George H. Williams 3 at the Mountain View (Maryland) lead mine. The minute quantities of sulphur found in marine muds are regarded by J. Y. Buchanan 4 as due to the oxidation of metallic sulphides, which are themselves produced by the action of 'animal digestive secretions on preexisting sulphates, mainly of iron and manganese. Localities. The principal localities of sulphur known in the United States are, iri alphabetical order: Alaska, California, Idaho, 1 Traite des Gites Mineraux et Metalliferes, I, p. 259. 2 The Mineral Industry, II, 1893, p. 585. 3 Johns Hopkins University Circulars, X, 1891, p. 74. 4 Proceedings of the Royal Society of Edinburgh, XVIII, 1890-91, p. 17. THE NON-METALLIC MINERALS. Louisiana, Nevada, Texas, Utah, and Wyoming. With the possible exception of those of Idaho and Texas, and that of Louisiana, these may all be traced to a solfataric origin. The Alaskan deposits, 1 accord- ing to Dall, are best developed on the islands of Kadiak and Akutan. California deposits have in times past been worked at Clear Lake, in Modoc County, in Colusa County, in Tehama County, and in Napa County. The Louisiana deposits lie in strata of Quaternary Age, and are derived from gypsum. The following facts relative to this deposit are from Professor Kemp's paper, already alluded to: " Probably the richest and geographically the most -accessible of the American localities is in southwestern Louisiana, 230 miles west of New Orleans and 12 miles from Lake Charles. The first hole which revealed this sulphur was sunk in search of petroleum, of which the presence of oil and tarry matter on the surface were regarded, quite justly, as an indication. While more or less of these bituminous substances were revealed by the drill, the great bed of sulphur is the main object of interest. A number of holes have since been put down with the results recorded below, and they leave no doubt that there is a very large body which awaits exploitation. The first explorations were made by the Louisiana Petroleum and Coal Oil Company. It was succeeded by the Calcasieu Sulphur and Mining Company. The Louisiana Sulphur Mining Company followed, and now the owners are the American Sulphur Company. The records of four holes are appended. Nos. i and 2 were the first sunk, and were about 150 feet apart. Nos. 2, 3, and 4 were put down in 1886. No. 3 is northwest of No. i." RECORDS OF SEVERAL OF THE BORE-HOLES THAT HAVE PENETRATED THE SULPHUR BED. Strata. Original Well No. i. Granet's Wells. Van Sloot- en's Well No. 5. American Sulphur Company. No. 2. No. 3. No. 4. No. 6. No. 7. No. 8. Clay, quicksand, and gravel. . . Soft rock 333 no 108 680 344 84 112 12 426 7 119 6 332 138 45 (a) 345 9 1 no 57 35 95 I2 5 3 2 37 72 126 30 499 44 5 2 (a) Sulphur bed, 70 to 80 per cent. Gypsum and sulphur. . ....... Depth of hole in feet 1,231 552 621 525 603 602 593 59 6 a. Stopped in sulphur. Alaska and its Resources, Boston, 1870. ELEMENTS. Analyses from the large bed in holes No. 2 and No. 3 gave the following : Depth. Sulphur. Depth. Sulphur. Hole No. 2. 428 feet Percent. 62 Hole No. 3. Per cent. 7O 7O 60 ACQ feet 80 4.0 feet 81 466 feet 83 e e 2 feet OI 486 feet QO 604 feet. .. ........ . 08 feet 80 y<_> feet 7c feet 80 68 The difficulties in development lie in the quicksands and gravel, which are wet and soft, and in the soft rock (hole i), which yields sulphurous waters under a head, at the surface, of about 15 feet. The Nevada deposits occupy the craters of extinct hot springs near Humboldt House. These craters are described by Russell 1 as situated on the open desert, above the surface of which they rise to a height of from 20 to 50 feet. " Nearly all of the cones are weathered and broken down, and are all extinct, the water now rising to the surface for miles around. The outer surface of the cones is composed of calcareous tufa and siliceous sinter, forming irregular imbricated sheets that slope away at a low angle from the orifice at the top. The interiors of these structures are filled with crystalline ' gypsum, which in at least two instances is impregnated with sulphur. One of the cones has been opened by a cut from the side in such a manner as to expose a good section of the material filling the interior, and a few tons of the sulphur and gypsum removed. The percentage of sulphur is small, and the economic importance of the deposit, as shown by the exca- vation already made, will not warrant the further expenditure of capital. The cone that has been opened is surrounded on all sides by a large deposit of calcareous and siliceous material, thus forming a low dome or crater, with a base many times as great in diameter as the height of the deposit. These cones correspond in all their essential features with the structures that surround hot springs that 1 Transactions of the New York Academy of Sciences, I, 1881-1882, p. 172. 16 THE NON-METALLIC MINERALS. are still active in various parts of the Great Basin, thus leaving no question as to their origin. They are situated within the basin of Lake Lahontan, and must have been formed and become extinct since the old lake ^evaporated away." Sulphur is reported as occurring in the chemically formed deposits that surrounded Steamboat Springs, situated midway between Car- son and Reno, Nevada. The conditions at these springs must be very similar to those that existed near Humboldt House at the time the cones containing the sulphur were formed. Sulphur is also said to occur in the Sweetwater Mountains, situated on the boundary between California and Nevada, in latitude 38 30'. The extent and geological relations of these deposits are unknown. Another illustration of sulphur deposits of the volcanic type is that furnished by the Rabbit-Hole Sulphur Mines. These are located in northwestern Nevada, on the eastern border of the Black Rock Desert, and derive their name from the Rabbit-Hole Springs, a few miles to the southward. The hills bordering the Black Rock Desert on the east are mainly of rhyolite, with a narrow band of volcanic tufa along the immediate edge of the desert. These beds of tufa are stratified and evidently water-lain, and are identical with tufa deposits that occur over an immense area in Oregon and Nevada. At the sulphur mines the tufas contain angular fragments of volcanic rock, and have been cemented by opal and other siliceous infiltra- tions since their deposition, so that they now form brittle siliceous rocks, with pebbles and fragments of older rocks scattered through the mass. In many places these porous tufas and breccias are richly charged with sulphur, which fills all the interstices of the rock and sometimes lines large cavities with layers of crystals 5 or 6 feet in thickness. In the Rabbit-Hole District sulphur has been found in paying quantities for a distance of several miles along the border of the desert, but the distribution is irregular and uncertain, and is always superficial, so far as can be judged by the present open- ings. The sulphur has undoubtedly been derived from a deeply seated source, from which it has been expelled by heat, and escaping upward along the lines of faulting, has been deposited in the cooler and higher rocks in which it is now found, though whether the deposition took place by direct sublimation or through the decompo- ELEMENTS. I? sition of hydrogen disulphide can not now be told with certainty. Judging from the siliceous material that cements the tufas, it is evident that the porous rocks in which the sulphur is now found were pene- trated by heated waters bearing silica in solution previous to the deposition of the sulphur. The mines occur in a narrow north- and-south belt along a line of ancient faulting which is one of the great structural features of the region. The association of faults with sulphur-bearing strata of tufa is here essentially the same as at the Cove Creek Mines, yet to be noted. At the Rabbit-Hole Mines, however, no very recent movement of the ancient fault could be determined. The absence of a recent fault- scarp, together with the fact that the mines are now cold and do not give off exhalations of gas or vapor, shows that the solfataric action at this locality has long been extinct, though at the Cove Creek Mines, mentioned below, the deposition is still in progress. According to A. F. Du Faur 1 this Cove Creek (Utah) deposit is in Beaver County, near Millard County line. It was first discovered in 1869, but owing to lack of railroad communications remained undeveloped until 1883. The region is one of comparatively recent volcanic activity. The sulphur occurs impregnating limestone and slate to such a degree that very pure pieces as large as one foot in diameter are obtainable. It also occurs impregnating a decomposed andesite. The Cove Creek Mines are situated about 2 miles south- east of Cove Creek fort and to the east of the Beaver road in a small basin near the foot of the Sulphur Mountains, surrounded by low hills, with a narrow ravine opening in the west-northwest direction into the plain. The basin is about 6,000 feet above the level of the sea, while the Sulphur Mountains to the east rise about 2,000 feet higher. The hills surrounding the basin consist mainly of andesite, partly also of a very light white trachyte. As far as explored, the sulphur bed extends at least 1,800 feet by 1,000 feet, and the quantity of sulphur contained therein was estimated by Professor vom Rath, at a time, when the bed was not as fully exposed as it now is, to be at least 1,300,000 tons. A curved cut has been made through the sulphur bed near the western end, exposing a vertical wall 34 feet high of rich yellow 1 Transactions of the American Institute of Mining Engineers, XVI, 1888, p. 33. i8 THE NON-METALLIC MINERALS. sulphur. The sulphur extends up to the surface over part of the basin, but is mostly covered with sand or rather decomposed ande- site. The surface of the deposit is wavy, giving the impression of an agitated mass gradually cooled. The sulphur is partly mixed with sand or gypsum. Most of it is yellow color, while some of it is dark gray, and is called " black sulphur." The deposits of pure sulphur partly resemble the so-called " virgin rock," which is formed as a product of distillation in the sulphur-flower chambers, par- ticularly when distillation goes on too rapidly. Some also resemble the delicate crystals formed on the walls of such chambers; others are like the crystals formed in slowly cooled masses of sulphur. Gases escape in many places in the cut and in the prospect holes, together with water hold- ing salts in solution. At some points also a con- siderably elevated temper- ature is observed. Of the foreign locali- ties of sulphur, the most noted at present are those of Sicily and Japan. The first-named deposits are described as occurring in Miocene strata involving, from below up, sandy marls with beds of salt, limy marls and lignite, gypsum and limestone impregnated with sulphur, black shales, and micaceous sands. Overlying all these is a white, marly Pleiocene limestone, while below the Miocene is the Eocene nummulitic limestone. The sulphur is found in veinlets and sometimes in larger masses, which ramify through the cellular limestone, as shown in Fig. 2. The yield in sulphur varies from 8 to 25 per cent, rarely running as high as 40 per cent. Below 8 per cent the rock can not be worked economically. More or less petroleum and bitumen are found in the mines. Barite and celestite sometimes accompany the sulphur. FIG. 2. Block of limestone (light) with alter- nating bands of sulphur (dark). Sicily. [U. S. National Museum.] ELEMENTS. 19 The mining regions are in the southern central portion of the island; Girgenti and Larcara are the chief centers. The mines are distributed over an area of 160 to 170 kilometers (about 100 miles) from east to west, and 85 to 90 kilometers (55 miles) from north to south. They occur in groups around centers, partly because the sulphur-bearing stratum is not continuous, and partly because the sulphur indications are concealed by later deposits. The region, moreover, is much faulted. According to Professor Kemp, the common methods of mining are of the crudest description. In most cases the deposits are reached by steep slopes or circular stairways ("scala"), with wide steps, up which boys laboriously bring the crude rock in baskets or sacks. No mine maps are made, and no precautions taken to work beds on a systematic scale Timbering or any supports for the roof are not generally thought of. A feeling of distrust prevails between the owners of the land and the operators, and between the latter and the miners. These objectionable features arise partly from the irregular nature and uncertainty of the deposits, partly from excessive sub- division of ownership and ill-adapted property laws, and partly from the local prejudices against innovations. Even in one case where an American and an Englishman in partnership secured the right to work a mine, and set about installing suitable hoisting machinery, they were hampered by a lawsuit with the owner because of this innovation, and had a long legal contention to establish their undoubted rights. It is a striking fact that in the new developments in Japan, on a remote island and against great natural difficulties, the most modern methods and management prevail, while in Sicily, in the center of the oldest civilization, these are to a great extent of the crudest. The Japanese sulphur deposits are all of volcanic origin, and the Abosanobori Mine, in Kushiro village, Kawakami-gori, Kushiro Province, Hokkaido, may be taken as fairly typical. The mine is on a conical-shaped mountain of augite andesite which, on its north- ern side, is open and looks down upon a plain covered with lava, and is shut in by the walls of the old crater on the other sides. Sulphur is found in different parts of these walls in massive heaps, and sulphur I 20 THE NON-METALLIC MINERALS. fumes still issue nearly everywhere about the mines. The ore as taken from the mines carries from 35 per cent to 90 per cent of sulphur, which is extracted by steam refining works at Hyocha, some 35 miles north of the mine. 1 Other Japanese localities are: The Aroya Mines, at Onikobe village, Rikuzen Province, and the active volcano of Icvo-San, in Yezo. In addition to these localities may be mentioned the following, in alphabetical order: Austria, Celebes, Egypt, France, Greece, Hawaii, Iceland, Italy, Mexico, New South Wales, New Zealand, Peru, Russia, Spain, and the West Indies. Extraction and preparation. Sulphur rarely occurs in nature in any quantity sufficiently pure for commercial purposes. In freeing it from its impurities three methods are employed: (i) Melting, (2) distillation, and (3) solution. In the first the ore is simply dry roasted at a low temperature or treated with superheated steam until the sulphur melts and runs off. The first process is extremely wasteful; the second much more economical in the end, but demand- ing a more expensive plant. A process of fusion in a calcium chloride solution has come into use of late years, and bids fair to yield better results than either of the above. In the distillation process the ore is heated in iron retorts until the sulphur distills off and is condensed in chambers prepared for it. The product is mostly in the form of " flower of sulphur." The method is expensive, but the resultant sulphur very pure. In the third process mentioned the ore is treated with carbon disulphide, which dissolves out the sulphur and from which it is recovered by evaporation. This method, while giving good results, is also expensive and somewhat dangerous, owing to the explosive nature of the gases formed. 2 Uses. Sulphur is used mainly for the making of sulphuric acid, though small amounts are utilized in the manufacture of matches, for medicinal purposes, and in the making of gunpowder, fireworks, insecticides, for vulcanizing india rubber, etc. In the manufacture of sulphuric acid the sulphur is burned to sulphurous anhydride (SO 2 ) on a grate and then conducted with a slight excess of air into large 1 The Mining Industry of Japan, by Wada Tsunashiro, 1893. 2 The Mineral Industry, II, 1893, p. 600. ELEMENTS. 21 lead lined chambers and mixed with steam and nitrous fumes, where the SO 2 is oxidized to the condition of SO 3 (sulphuric anhydride) and takes up water from the steam forming H 2 SO 4 (sulphuric acid). Ordinary roll sulphur is quoted in the current price-lists at from ij to 2\ cents per pound. (See also under iron pyrites, p. 31.) BIBLIOGRAPHY. R. PUMPELLY. Sulphur in Japan. Geological Researches in China, Mongolia, and Japan. Smithsonian Contri- butions, XV, 1867, p. ii. I. C. RUSSELL. Sulphur Deposits of Utah and Nevada. Transactions of the New York Academy of Science, I, 1882, p. 168. A. FABER DU FAUR. The Sulphur Deposits of Southern Utah. Transactions of the American Institute Mining Engineers, XVI, 1887, p. 33. The Sulphur Mines of Sicily. Engineering and Mining Journal, XL VI, 1888, p. 174. V. LAMANTIA. Sulphur Mines of Sicily. U. S. Consular Repojt No. 108, 1889, pp. 146-155. 3. ARSENIC. This substance occurs native in the form of a brittle, tin-white metal, with a specific gravity of 5.6 to 5.7 and a hardness equal to 3.5 of the scale. On exposure it becomes dull black on the imme- diate surface. It is found, as a rule, in veins in the older crystalline rocks associated with antimony and ores of gold and silver. Some of the more celebrated localities for the mineral, as given by Dana, are the silver mines of Freiberg, Annaberg, Marienberg, and Schnee- berg in Saxony; Joachimsthal in Bohemia; Andreasberg in the Harz; Kapnik and Orawitza in Hungary; Kongsberg in Norway; Zmeiv in Siberia; St. Maria aux Mines, Alsace; Mount Corna dei Darden, Italy; Chanarcillo, Chile; San Augustin, Hidalgo, Mexico, and New Zealand. In the United States it has been found at Haverhill, New Hampshire; Greenwood, Maine; near Leadville, Colorado; and on Watson Creek, Frozen River in British Columbia. The arsenic of commerce is, however, rarely obtained from the native mineral, but is prepared by the ignition of arsenical pyrites (FeAs 2 ) or arsenical iron pyrites (FeS 2 ,FeAs 2 ). The white arsenic of commerce (arsenious acid, As 2 O 3 ), though occurring sometimes native as arsenolite in the form of botryoidal and stalactitic crusts 22 THE NON-METALLIC MINERALS. of a white or yellowish color, is, as a rule, obtained as a by-product in the metallurgical operations of extracting certain metals, particu- larly cobalt and nickel, from their ores. Such ores as Niccolite, a nickel arsenide (NiAs), Gersdorffite NiAsS), Rammelsbergite (NiAs 2 ), Smaltite (CoAs 2 ), Skutterudite (CoAs 3 ), Proustite (Ag 3 AsS 3 ), and other arsenides and sulpharsenides on roasting give up their arsenic in the form of fumes, which are condensed in chambers prepared for this purpose. Uses. Arsenic is utilized in the form of arsenious acid (As 2 O 3 ) in dyeing, calico printing, in the manufacture of various pigments, in arsenical soaps, in the preparation of other salts of arsenic, and as a preservative in museums, particularly for the skins of animals and birds. 4. ALLEMONTITE. Allemontite, or arsenical antimony of the formula SbAs 3 , = arsenic, 65.2; antimony, 34.8, occurs somewhat sparsely at Alle- mont in France, Pribram, Bohemia, and other European localities associated with sphalerite, antimony, etc. So far as the writer has information the mineral has not as yet been found in sufficient quantity to be of economic value. II. SULPHIDES AND ARSENIDES. I. REALGAR AND ORPIMENT. Realgar is a monosulphide of arsenic, AsS, = arsenic, 70.1 per cent, sulphur, 29.9 per cent. Hardness, 1.5 to 2; brittle; specific gravity, 3.55; color, aurora-red to orange-yellow; luster, resinous; streak the color of the mineral. Orpiment, or auripigment as it is also called, is a trisulphide of arsenic of the formula As 2 S 3 , = arsenic, 61 per cent, sulphur, 39 per cent. Hardness and specific gravity essentially the same as realgar, with which it is commonly associated. Occurrences. Realgar and orpiment are very beautiful, though not abundant minerals which occur associated with ores of silver and lead in various European mining regions and also those of Japan, Hungary, Bohemia, Transylvania, and Saxony. They have been SULPHIDES AND ARSENIDES. 23 reported in the United States in beds of sandy clay beneath lava in Iron County, Utah, and form the so-called " Arsenical gold ore" of the Golden Gate Mine, Mercur, Tooele County, this same State, also in San Bernardino County, California ; Douglas County, Oregon, and in minute quantities in the geyser waters of the Yellowstone National Park. The realgar and orpiment of the Coyote mining district, Iron County, Utah, occur in a compact, sandy clay, occupying a horizontal seam or layer about 2 inches thick, not distinctly separated from the clay, but lying in its midst in lenticular and nodular masses. The bulk of the layer consists of realgar in divergent, bladed crystals, closely and confusedly aggregated, sometimes forming groups of brilliant crystalline facets in small cavities toward the center of the mass. The orpiment is closely associated with the realgar in the form of small and delicately fibrous crystalline rosettes and small spherical aggregations made up of fine radial crystals, and also in bright yellow, amorphous crusts in and around the mass of the realgar. Fine parallel seams of gypsum occur both above and below the layer, and the strata of arenaceous clays above for 30 feet or more are charged with soluble salts which exude and effloresce upon the surface of the bank, forming hard crusts. The whole appearance and association of the minerals indicates that they have been formed by aqueous infiltration since the deposition of the beds. 1 Orpiment is said 2 to occur at Tajowa, near Neusohl, Hungary, as nodular masses and isolated crystals in clay or calcareous marl. Uses. Realgar is used mainly in pyrotechny, yielding a very brilliant white light when mixed with saltpeter and ignited. It is now artificially prepared by fusing together sulphur and arsenious acid. 3 Orpiment is used in dyeing and in preparation of a paste for removing hair from skins. According to the British consular reports there were exported from Baghdad in 1897, some 55,600 pounds of the mineral for use as a pigment. As with realgar, the mineral is now largely prepared artificially. The name orpiment 1 W. P. Blake, American Journal of Science, XXI, 1881, p. 219. 3 H. A. Miers, Mineralogical Magazine, July, 1892, p. 24. 8 Wagner's Chemical Technology, p. 87. THE NON-METALLIC MINERALS. is stated by Dana to be a corruption of auripigment, golden paint, in allusion to the color. BIBLIOGRAPHY. W. P. BLAKE. Occurrence of Realgar and Orpiment in Utah Territory. American Journal of Science, XXI, 1881, p. 219. H. B. FULTON. Arsenic in Spanish Pyrites, and its elimination in the local treat- ment for production of copper precipitate. Journal of the Society of Chemical Industry, V, 1886, p. 296. Production of Arsenic in Cornwall and Devon. Engineering and Mining Journal, LII, 1891, p. 96. WILLIAM THOMAS. Arsenic. The Mineral Industry, II, 1893, p. 25. 2. COBALT MINERALS. Several minerals contain cobalt as one of their essential con- stituents in sufficient quantity to make them of value as ores. In other cases the cobalt exists in too small quantities to pay for working for this substance alone, and it is obtained as a by-product during the process of extraction of other metals, notably of nickel. The common cobalt-bearing minerals, together with their chemical com- position, mode of occurrence, and other characteristics, are given below : Cobaltite. Cobaltine, or cobalt glance. This is a sulphar- senide of cobalt of the formula CoAsS, = sulphur, 19.3 per cent; arsenic, 45.2 per cent; cobalt, 35.5 per cent; hardness, 5.5, and specific gravity 6 to 6.3. The luster is metallic and color silver- white to reddish. When in crystals, commonly in cubes or pyrito- hedrons. Analysis of a massive variety from I, Siegen, Westphalia ; II, Skutterud, Norway, and III and IV, Daschkessan, in the government of Elizabethpol, Caucasus, as given by various authori- ties, yielded results as below: Constituents. I. II. III. IV. Arsenic 4 r } A'i j6 ?r 07 7T 17-1 Sulphur . IQ 3 ^ 20 08 Cobalt. . . ?} 71 2 ? JO 17 QO 17 ^ ^ Iron 63- I *- I 6"? 323 I 44. Q 8< Nickel O 22 o 26 Undetermined 4.4 26 4.O 71 I SULPHIDES AND ARSENIDES. 25 In Saxony the mineral occurs in lodes in gneiss and in which heavy spar (barite) forms the characteristic gangue. It is associated with other metallic sulphides, notably those of lead and copper. At Skutterud and Snarum, Norway, the cobaltiferous fahlbands, accord- ing to Phillips, 1 "occur in crystalline rocks varying in character be- tween gneiss and mica schists, but from the presence of hornblende they sometimes pass into hornblende schists ; among the accessory min- erals are garnet, tourmaline, and graphite. These schists, of which the strike is north and south, and which have an almost perpendicular dip, contain fahlbands very similar in character to those of Kongs- berg. They differ from those of that locality, however, inasmuch as while here the fahlbands are often sufficiently impregnated with ore to pay for working, those of Kongsberg, although to some extent containing disseminated sulphides, are only of importance as zones of enrichment for ores occurring in veins. The ore zones usually follow the strike and dip of the surrounding rocks, and vary in breadth from 2j to 6 fathoms. The distribution of the ores is by no means equal, since richer and poorer layers have received special names and are easily recognized. The Erzbander, or ore bands, are dis- tinguished from the Reicherzbander, or rich ore bands, while the bands of unproductive rock are known as Felsbander. The predomi- nant rock of the fahlbands is a quartzose granular mica schist, which gradually passes into quartzite, ordinary micha schist, or gneiss. The ores worked are cobalt glance, arsenical and ordinary pyrites containing cobalt, skutterudite, magnetic iron pyrites, copper pyrites, molybdenite, and galena. It is remarkable that in these mines nickel ores do not accompany the ores of cobalt in any appreciable quantity. The principal fahlband is known to extend for a distance of about 6 miles, and is bounded on the east by a mass of diorite which protrudes into the fahlband, while extending from the diorite are small dikes or branches traversing it in a zigzag course. It is also intersected by dikes of coarse-grained granite which contain no ore, but which penetrate the diorite." The Skutterud Mine in 1879 produced 7,700 tons of cobalt ore, 1 Ore Deposits, by J. A. Phillips) p. 389. 26 THE NON-METALLIC MINERALS. which yielded 108 tons of cobalt schlich (concentrates), containing from 10 to ii per cent of cobalt, and worth about 11,000. At Daschkessan the ore occurs under a shee. of diabase, the cobaltite being in the wall rock of this sheet, and which carries also garnets and copper pyrites. In 1887, 1,216 kilograms of the mineral were extracted; in 1888, 928 kilograms, and in 1889, 12,960 kilograms, besides some 3,000 kilograms of cobaltiferous matter obtained in treating the cobaltiferous copper ores. 1 Smaltite. This is essentially a cobalt diarsenide of the formula CoAs 2 , = arsenic, 71.8 per cent; cobalt, 28.2 per cent; hardness, 5.5 to 6; specific gravity, 6.4 to 6.6. Color, white to steel-gray. Through the assumption of nickel the mineral passes by gradations into chloanthite. Analyses of samples from (I) Schneeberg, Saxony, and (II) Gun- nison County, Colorado, as given by Dana, yielded results as below Constituents. I. II. Arsenic. . 71 ^ 3 63 82 Sulphur. .. . . I 38 I ^ ^ Cobalt A -v3 y iron. The mineral is found at Huasco, Chile, associated with cobaltite in a chloritic schist. The name allodasite is given to a variety of glaucodot con- taining bismuth and answering to the formula Co(As,Bi)S. The composition as given is somewhat variable. Arsenic, 28 to 33 per cent; bismuth, 23 to 32 per cent; sulphur, 16 to 18 per cent; cobalt, 20 to 24 per cent; iron, 2.7 to 3.8 per cent. It is reported only from Orawitza, Hungary. Linnaeite is a sulphide of cobalt with the formula Co 3 S 4 , = sul- phur, 42.1 per cent; cobalt, 57.9 per cent; a part of its cobalt is com- monly replaced by nickel, giving rise to its variety siegenite. The mineral is brittle, of a pale steel-gray color, tarnishing red. Hard- ness, 5.5 and specific gravity, 4.8 to 5. When crystallized it is com- monly in octahedrons. The following analyses of a nickel-bearing variety (siegenite) are quoted from Dana: Constituents. S. CO. Ni. Pe. Cu. Ivfiisen, Prussia. 4.1 OO 4.1 86 57T Mineral Hill, Maryland. . Mine La Motte, Missouri. 39-70 41-54 25.69 21.34 29.56 30-53 '^ 1.96 3-37 2.23 Trace. The mineral occurs in gneiss in Sweden ; with barite and siderite a Miisen ; in limestone with galena and dolomite at Mine La Motte, Missouri, and with sulphides of iron and copper in chloritic schists in Maryland. Sychnodymite has the formula (Co,Cu) 4 S 5 , and yields sulphur, 40.64 per cent; copper, 18.98 per cent; cobalt, 35.79 per cent; nickel, 3.66 per cent; iron, 0.93 per cent. It is of a steel-gray color, metallic luster, and has a specific gravity of 4.75. 28 THE NON-METALLIC MINERALS. Erythrite or cobalt bloom is the name given to a hydrous cobalt arsenate of the formula Co 3 As 2 O 8 +8H 2 O, = arsenic pentoxide, 38.4 per cent; cobalt protoxide, 37.5 per cent, and water, 24.1 per cent. It occurs in globular and remform shapes and earthy masses of a crimson to peach-red color associated with the arsenides and sulpharsenides mentioned above and from which it is derived by a process of oxidation. In Churchill County, Nevada, it occurs as a decomposition product of a cobalt-bearing niccolite. It is also found at the Kelsey Mine, Compton, in Los Angeles County, Cali- fornia; associated with cobaltite at Tambillo and at Huasco, Chile, and under similar conditions in various parts of Europe. Asbolite or earthy cobalt, is a black and earthy ore of man- ganese (wad) which sometimes carries as high as 30 per cent of cobaltic oxide. It takes its name from the Greek ao-fiohaivGo, to soil like soot. Roselite is an arsenate of lime, magnesia, and cobalt with the formula (Ca,Co,Mg) 3 As 2 O 8 ,2H 2 O, = arsenic pentoxide, 51.4 per cent; lime, 28.1 per cent; cobalt protoxide, 12.5 per cent; water, 8 per cent. It is of a light to dark rose-red color; hardness, 3.5; specific gravity, 3.5 to 3.6, and vitreous luster. Sphaero- cobaltite is a cobalt protocarbonate of the formula CoCO 3 , = carbon dioxide, 37.1 per cent; cobalt protoxide, 62.9 per cent. It is also of a rose-red color, varying to velvet-black. Hardness, 4, and specific gravity, 4.02 to 4.13. It occurs but sparingly, associated with roselite at Schneeberg in Saxony. Remingtonite is a hydrous carbonate the exact composition of which nas not been ascertained. Cobalto- menite is a supposed selenide of cobalt. Bieberite, or cobalt vitriol, is a sulphate of the formula CoSO 4 + 7H 2 O. The color is flesh to rose-red. It is soluble in water, has an astringent taste, and occurs in secondary stalactitic form. Pateraite is a possible molybdate of cobalt. Aside from the possible sources mentioned above, cobalt occurs very constantly associated with the ores of nickel (niccolite, millerite, chloanthite, etc.), and is obtained as a by-product in smelting. Con- siderable quantities have thus from time to time been obtained from the Gap Mines of Pennsylvania, Mine La Motte, Missouri, and Lovelock, Nevada. The nickel mines of New Caledonia are perhaps SULPHIDES AND ARSENIDES. 29 the most productive. The ore here, a silicate, carries some 3 per cent of cobalt protoxide. A vein of cobalt ore near Gothic, Gunnison County, Colorado, is described as lying in granite, the gangue material being mainly calcite, throughout which was disseminated the ore in the form of smaltite. With it were associated erythrite, a small amount of iron pyrites, and native silver. An analysis of this ore yielded as below: Cobalt ii. 59 Bismuth. Iron IJ -99 Arsenic 63.82 Silica 2 . 60 Lead 2 . 05 Sulphur 1.55 A cobalt ore, consisting of a mixture of glaucodot and erythrite, occurring near Carcoar Railway Station, New South Wales, has the composition given below: i *3 Copper o. 16 Nickel Trace. Silver Trace. 94-89 Constituents. I. II. Moisture. ....... ................... .120 2 180 Metallic arsenic 51.810 29 oio Metallic cobalt 10.447 17 830 Metallic nickel . ^QO . 390 IVIetallic iron II 860 IS 78 Alumina . . . Trace. M^etallic manganese. ... ..... Nil. Nil. M!etallic calcium. .... ........... ... Nil. 71 M^a^nesium ..................... i 480 22 Gold Trace. Trace. i . ^20 II .24 Gangue (insoluble in acids). . ... . . 22 O78 26 31 Specific gravity. . . . .................. 99.905 543 99.67 According to the Annual Report, Department of Mines, for 1888, this ore occurs concentrated in irregular hollows and bunches, often intimately mixed with diorite in a line of fissure between an intrusive diorite and slate, the fissure running for some distance follow- ing the line of junction between the two rocks, and being presumably formed at the time of the extrusion of the diorite. Other cobalt ores, carrying from 13 to 15 per cent of cobalt oxide, occur near Nina. 1 1 Complete analyses of these are given in Catalogue of the New South Wales Exhibit, World's Columbian Exposition, Chicago, 1893, p. 330. 30 THE NON-METALLIC MINERALS. Uses. Cobalt is produced and sold in the form of oxide and used mainly as a coloring constituent in glass and earthern wares. Only some 200 tons are produced annually the world over. The market value of the material is variable, but averages about $2 a pound. BIBLIOGRAPHY. FucHS erDs LAUNAY. TraitS des Giles Min6raux, II, pp. 75-91. 3. ARSENOPYRITE ; MISPICKEL; OR ARSENICAL PYRITES. Composition. Somewhat variable. Essentially a sulpharsenide of iron of the formula FeAsS, or FeS 2 , FeAs 2 ,= arsenic, 46 per cent; sulphur, 19.7 per cent, and iron, 34.3 per cent. The name danaite is given to a cobaltiferous variety. The specific gravity of the mineral varies from 5.9 to 6.2. Hardness, 5.5 to 6. Colors, silver-white to steel-gray; streak, dark gray to black; luster, metallic. Brittle. Occurrence. The mineral occurs principally in crystalline rocks, and is a common associate of ores of silver, gold, tin, and lead. It is at times highly auriferous, forming a valuable ore of gold, as in New South Wales and more rarely in California and Alaska. It is found in nearly all the States bordering along the Appalachian Mountain system, but in no instance is regularly mined excepting incidentally in the process of working other metals. Concerning its occurrence abroad Dana states that it is "abundant at Freiberg and Munzig, where it occurs in veins; at Reichenstein in Silesia in serpentine; at Auerbach in Baden; in beds at Breitenbrunn and Raschau, Andreasberg and Joachimsthal; at Tunaberg in Sweden; at Skutterud in Norway; at Wheal Mawdlin and Unanimity, Corn- wall, and at the Tamar Mines in Devonshire, England, and in Bolivia." Uses. The only use of the mineral is as an ore of arsenic. 4. LOLLINGITE; LEUCOPYRITE. The prismatic arsenical pyrites, or leucopyrite, is essentially a. diarsenide of iron, with the formula FeAs 2 , though usually contami- nated with a little sulphur and not infrequently cobalt, bismuth, or antimony. It has a specific gravity of 7 to 7.4, hardness of 5 to 5.5, metallic luster, and silver- white to steel-gray color. SULPHIDES AND ARSENIDES. 3 1 The mineral has been found at Edenville, New York; Roxbury, Connecticut, and other places in the United States, and associated with other arsenides and sulpharsenides in the gold and silver mines of Europe. 5. PYRITES. Two forms of the disulphide of iron are common in nature. The first, known simply as pyrite or iron pyrites, occurs in sharply defined cubes and their crystallographic modifications, or in granular masses of a brassy-yellow color. The second, identical in composition, crystallizes in the orthorhom- bic system, but is more common in concretionary, botryoidal, and stalactitic forms, which are of a dull grayish-yellow color. This form is known as the gray iron pyrites. Both forms have the chemical composition, FeS 2 , = iron, 46.6 per cent and sulphur, 53.4 per cent. The ore as mined is, however, never chemically pure, but con- tains admixtures of other metallic sulphides, besides, at times, con- siderable quantities of the precious metals. The following analyses 1 of materials from well-known sources will serve to show the general variation : Constituents. I. II. III. IV. V. VI. VII. Sulphur. . ..... 48.0 48.0 48.02 40.00 47.76 46.40 4=;. 60 Iron 43-O 44.0 ,42.01 3S.OO 43-99 30.00 38. S2 Copper i 6 i 6 4OO *.6o I ^O Zinc i f I e O.24 6 oo Silica c o 7 7 7 60 20 oo 1. 00 9.2 at St. Clair, St. Clair County, at a depth of 1,635 feet, and with a thickness of 35 feet. At Caseville, in Huron County, the beds lie -at a depth of 1,164 feet, and at Bay City, Saginaw Bay, at 2,085 ^ eet > tne salt beds being 115 feet in thickness. At Manistee the bed is 34 feet thick, lying 2,000 feet below the surface, while at Muskegon, in the Mason well, it was 50 feet thick at a depth of 2,200 feet. Although of so recent develop- ment, Michigan is rapidly becoming one of the leading salt-producing regions of the world, the estimated manufacturing capacity being now upward of 5,000,000 barrels annually. The total product of all the years since 1868 is given as 60,614,464 barrels of 280 pounds each. In Kansas the rock salt occurs in beds regarded as of Permian 1 For a very complete historical and geological account of these salt beds and the method of manufacture, see Bulletin No. n, of the New York State Museum, 1893, by F. J. H. Merrill. HALIDES. 45 Age, and has been reached by means of shafts in several counties in the southern and central part of the State. The following is a section of a shaft sunk at Kingman in 1888-89: Feet. "Red-beds," red arenaceous, limestones, ferruginous clays, and clay shales with thin streaks of gray shales and bands of gypsum as satin spar 450 Gray or bluish "slate," with 2 feet of limestone at 500 feet 140 Red clay shale 4 Gray "slate," with occasional streaks of limestone, 2 to 8 inches thick, and some salt partings and satin spar with ferruginous stain 78 First rock salt, pure white 2 Shale and "slate," bluish, with vertical and other seams of salt, from i to 3 inches thick 26 Rock salt 4 Shales, with salt n Rock salt 7 Shale 3 Rock salt 3 Salt and shale, alternate thin seams 62 Rock salt ii Shale I& Rock salt 5 Shales and limestone 8 Rock salt, bottom of it not reached 5 Total 820 Borings and shafts have also proven the existence of beds of salt in other parts of the State, as at Kanopolis, Lyons, Caldwell, Rago, Pratt, and Wilson. According to Dr. Robert Hays 1 it is safe to- assume that beds of rock salt from 50 to 150 feet in thickness under- lie fully half the area from the south line of the State to north of the Smoky River, an area from 20 to 50 miles in width. Although the mining of rock salt began in this region only in 1888, the annual output has already reached over 1,000,000 barrels. Louisiana. Salt in this State is derived from Petite Anse, a small island rising from the marshes on the southern coast and con- nected with the mainland by a causeway some 2 miles in length. According to E. W. Hilgard 2 the deposit is probably of Cretaceous Age, and is presumably but a comparatively small residual mass 1 Geological and Mineral Resources of Kansas, 1893, p. 44. 2 Smithsonian Contributions to Knowledge, XXIII. On the Geology of Lower Louisiana and the Salt Deposit on Petite Anse Island. 4 6 THE NON-METALLIC MINERALS. I: ii g| 4 6 s w l ? o S MAUDES. 47 of beds once extending over a much larger area, but now lost through erosion. (See Fig. 4.) Exploration has shown the area occupied by the beds to be some 150 acres, but the full thickness, though known to be upward of 165 feet, has never been fully determined. Kentucky. Salt in Kentucky is obtained from the brine of springs and wells in Carboniferous limestone. In Meade County brine accompanies the natural gas, the latter in some cases being utilized as fuel for its evaporation. Springs in Webster County furnished salt for Indians long anterior to the occupancy of the county by whites, and fragments of their clay kettles and other utensils used in the work of evaporation are still occasionally found. Texas. The occurrences of salt are numerous and widespread. Along the coast are many lagoons and salt lakes, from which con- siderable quantities are taken annually. " Besides the lakes along the shores many others occur through western Texas, reaching to the New Mexico line, while northeast of these, in the Permian region, the constant recurrence of such names as Salt Fork, Salt Creek, etc., tell of the prevalence of similar conditions." In addition to the brines there are extensive beds of rock salt. That which is at present best developed is located in the vicinity of Colorado City, in Mitchell County. The bed of salt was found at a depth of 850 feet, with a thickness of 140 feet. In eastern Texas there are many low pieces of ground called salines, where salt has been manufac- tured by evaporation of the brines obtained from shallow wells. At the " Grand Saline" in Van Zandt County, a bed of rock salt over 300 feet in thickness was found at a depth of 225 feet. In England the salt occurs at Cheshire in two beds interstratified with marls and clays. The upper, with a thickness varying from 80 to 90 feet, lies at a depth of some 120 feet below the surface, and the second at a depth of 226 feet has a thickness varying between 96 and 117 feet. The accompanying general sections are from Da vies' Earthy and other Economic Minerals. DETAILED SECTION OF STRATA SUNK THROUGH AT WITTON, NEAR NORTHWICH, TO THE LOWER BED OF SALT. Ft. In. 1. Calcareous marl 15 o 2. Indurated red clay 4 6 3. Indurated blue clay and marl 7 o 48 THE NON-METALLIC MINERALS. Ft. In. 4. Argillaceous marl i o 5. Indurated blue clay i o 6. Red clay with sulphate of lime in irregular branches 4 o 7. Indurated red clay with grains of sulphate of lime interspersed 4 o 8. Indurated brown clay with sulphate of lime crystallized in irregular masses and in large proportions 12 o 9. x lndurated blue clay with laminae of sulphate of lime 4 6 10. Argillaceous marl 4 o 11. Indurated brown clay laminated with sulphate of lime 3 o 12. Indurated blue clay laminated with sulphate of lime 3 o 1.3. Indurated red and blue clay 12 o 14. Indurated brown clay with sand and sulphate of lime irregularly inter- spersed through it. The fresh water, at the rate of 360 gallons a minute, forced its way through this stratum 13 o 15. Argillaceous marl 5 o 1.6. Indurated blue clay with sand and grains of sulphate of lime 3 9 17. Indurated brown clay as next above 15 o 18. Blue clay as strata next above i 6 19. Brown clay as strata next above 7 o 20. The top bed of rock salt 75 o 21. Layers of indurated clay with veins of rock salt running through them 31 6 22. Lower bed of rock salt 115 o Total 341 9 At Wieliczka, in Austrian Poland, the salt occurs in massive beds stated to extend over an area some 20 by 500 miles, with a maximum thickness of 1,200 feet. At Parajd, in Transylvania, beds belonging to the same geological horizon are estimated to contain upward of 10,000,000,000,000 cubic feet of salt. One of the most remarkable deposits of the world, remarkable for its extent as well as for the variety of its products, is that of Stassfurt, in Prussian Saxony. On account of its unique character, as well as its commercial importance, being to-day the chief source of natural potash salts of the world, a little space may well be given here to a detailed description. 1 " Stassfurt is a small town of some 12,000 inhabitants, about 25 miles southwest of the city and fortress of Magdeburg, in Prussia. It lies in a plain, and the river Bode, which takes its rise in the Harz Mountains, flows through it. The history of the salt industry in Stassfurt is a very old one, and dates back as far as the year 806. 1 Journal of the Society of Chemical Industry, II, 1883, pp. 146, 147. HALIDES. 49 Previous to the year 1839 the salt was produced from brine pumped from wells sunk about 200 feet into the rock. The brine, in the course of time, became so weak as regards the common salt it con- tained, that it was impossible to carry on the manufacture from FIG. 5. Cluster of sylvite crystals, showing characteristic cubo-octahedral forms. Stassfurt, Germany. [U. S. National Museum.] this source without loss. In 1839 tne Prussian Government, who were the owners of these saline springs, commenced boring with the object of discovering the whereabouts of the bed of rock salt from which the brine had been obtained, and in the year 1843, seven years after the commencement of the borings, the top of the rock salt was reached at a depth of 256 meters. The boring was con- tinued through another 325 meters into the rock salt without reach- ing the bottom of the layer. At this total depth of 581 meters the 50 THE NON-METALLIC MINERALS. boring was suspended. On analyzing the brine obtained from the bore-hole, it was found to consist, in 100 parts by weight, of Sulphate of calcium 4.01 Chloride of potassium 2.24 Chloride of magnesium I 9-43 Chloride of sodium 5.61 "A result not only unexpected but disappointing, since the presence of chloride of magnesium in such quantities dispelled for the time all hopes of striking on the pure rock salt. The Government, however, guided by the opinions expressed by Dr. Karsten and Professor Marchand, namely, that the presence of chloride of mag- nesium in such quantities was probably due to a deposit lying above the rock salt, determined to further investigate the matter, and in the year 1852 the first shaft was commenced, which after five years had penetrated, at a depth of 330 meters, into a bed of rock salt, passing on its way, at a depth of 256 meters, a bed of potash and magnesia salts of a thickness of 25 meters. " On referring to the section of the mines (Plate II) it will be seen that the lowest deposit of all consists of rock salt. The bore-hole was driven 381 meters into it without reaching the bottom of the layer. Its depth is therefore unknown. The black lines drawn across the rock-salt deposit represent thin layers of sulphate of oal- cium 7 millimeters thick, and almost equidistant. The lines at the top of the rock salt represent thin layers of the trisulphate of potash, magnesia, and lime as the mineral Polyhallite. The deposit lying immediately on the bed of rock salt consists chiefly of sulphate of magnesia as the mineral Kieserite. Still farther toward the surface the deposit consists of the double chloride of potassium and mag- nesium, known as the mineral Carnallite, mixed with sulphate of magnesia and rock salt. The deposit to the right, on the rise of the strata, consists of the double sulphate of potash and magnesia combined with one equivalent of chloride of magnesium, and inter- mingled with common salt to the extent of 40 per cent. This double sulphate is known as the mineral Kainite and is a secondary forma- tion, resulting from the action of a limited quantity of water on a mixture of sulphate of magnesia and the double chloride of potassium Prussian Shafts. SECTION or TH e SALT DEPOSITS AT STASSRJRT : 5000 PLATE II. [U. S. National Museum.] OF THE UNIVERSITY OF MAUDES. and magnesium, as contained in the uppermost deposit previously spoken of. " The upper bed of the rock salt, resting on a thick bank of Anhy- drite, is also a later formation. Almost imperceptible layers of Polyhallite are present in this deposit and at greater intervals than in the lower and older deposit. It has therefore probably originated from the action of water on the older deposit. This upper bed of rock salt varies in thickness from 40 to 90 meters, and its extent is comparatively limited. It is worked in preference to the older deposit, where both exist in the same mine, it being of much purer quality, averaging about 98 per cent in the mines of the New Stass- furt Mining Company and in the Royal Prussian mines. " Sixteen different minerals have as yet been discovered in the Stassfurt deposits. They may be divided into primary and second- ary formations. Those of primary formation are rock salt, Anhy- drite, Polyhallite (K 2 SO 4 , MgSO 4 , 2CaSO 4 , 2H 2 O) Kieserite (MgSO 4 , H 2 O), Carnallite (KC1, MgCl 2 , 6H 2 O), Boracite (2(Mg 3 B 8 O 15 ), MgCl 2 ), and Douglasite (2KC1, FeCl 2 , 2H 2 O). Those of secondary formation, resulting from the decomposition of the primary minerals are nine in number, namely : Kainite (K 2 SO 4 , MgSO 4 , MgCl 2 6H 2 O) ; Sylvin (KC1); Tachydrite (CaCl 2 , 2MgCl 2 + i2H 2 O); Bischofite (MgCl 2 , 6H 2 O); Krugite (K 2 SO 4 , MgSO 4 , 4CaSO 4 , 2H 2 O); Reich- ardtite (MgSO 4 , 7H 2 O); Glauberite (CaSO 4 , Na 2 SO 4 ); Schonite (K 2 SO 4 , MgSO 4 , 6H 2 O), and Astrakanite (MgSO 4 , 4H 2 O). Only four of these minerals have any commercial value, namely: Car- nallite, Kainite, Kieserite, and rock salt. The yield of boracite, which is found in nests in the Carnallite region of the mine, is too insignificant to be classed among those just mentioned. " The mine may be divided chemically into four regions: (i) The rock salt, (2) the Kieserite, (3) the Carnallite, (4) the Kainite region. " The rock-salt region has almost the same composition through- out. Its character is crystalline, though in this region well-defined crystals are never met with. In other parts of the mine, especially in the Carnallite region, it is found crystallized in the form of the cube and the octahedron, sometimes coloured different shades of red and blue. Specimens have also been found of varied structure, laminated, granular, and fibrous. 52 THE NON-METALLIC MINERALS. " The deposit lying on the top of the rock constitutes the so-called Kieserite region. The thickness of this deposit is about 56 meters, and its average composition as follows: Per cent. Kieserite 17 Rock salt 66 Carnallite 13 Tachydrite 3 Anhydrite 2 100 "In the pure state Kieserite is amorphous and translucent, pos- sessing a specific gravity of 2.517. It contains 87.1 per cent sulphate of magnesia and 12.9 per cent water, corresponding to the formula MgSO 4 ,H 2 O. Exposed to the air it becomes opaque from the absorption of moisture, and is converted into Epsom salts; 100 parts of water dissolve 40.9 parts of this mineral at 18 C. The solution, however, takes place very slowly at this temperature. " This deposit has not been worked to any great extent. Its com- position is interesting as showing the gradual decrease of the propor- tion of common salt and the commencement of the separation of the more soluble salts. " Each of the two divisions of the mine just described contains only one mineral of importance. The third division, called the Carnallite region, contains a variety of minerals, and to this deposit Stassfurt owes its world- wide fame. The average thickness of this deposit is about 25 meters, and its composition is as follows: Per cent. Carnallite 60 Kieserite 16 * Rock Salt 20 Tachydrite 4 besides small quantities of magnesium bromide. These minerals are deposited in the order given above, in successive layers, varying in thickness from ^ to i meter, the different colors of these minerals giving the deposit a remarkable appearance. HALIDES. 53 " The predominating mineral in this region is Carnallite, a double chloride of potassium and magnesium, containing 26.76 per cent chloride of potassium, 34.50 per cent chloride of magnesium, and 38.74 per cent water, corresponding to the formula KCl,MgCl 2 ,6H 2 O. In the pure state it is colorless and transparent, and possesses a specific gravity of 1.618. It is very hygroscopic, and is easily soluble in water, 100 parts of which dissolve 64.5 parts of the mineral. It may be artificially formed from a solution of chloride of potassium, con- taining not less that 26 per cent of chloride of magnesium. The deposit which figures to the right of the Carnallite region is, as before mentioned, a secondary formation, and consists principally of the mineral Kainite. This deposit, though limited as compared to the other salt deposits, is yet of vast extent. The average compositon of this deposit is: Sulphate of potash 23.0 Sulphate of magnesia. . 15.6 Chloride of magnesium 13.0 Chloride of sodium 34.8 Water 13.6 100.0 " In the pure state it is colorless and almost transparent, and pos- sesses a specific gravity of 2.13; 100 parts of water dissolve 79.5 parts of it. Cold water does not decompose it, but from its saturated hot solution the double sulphate of potash and magnesia separates, and chloride of magnesium remains in solution." Methods of mining and manufacture. In the manufacture of salt three principal methods are employed. The first, if, indeed, it can be called manufacture, consists in mining the dry salt from an open quarry, as in the Rio Virgen and Barcelona deposits, or by means of subterranean galleries, the methods employed at Petite Anse and in Galacia. At Petite Anse the method of mining and preparation, as given by Mr. R. A. Pomeroy, 1 is as follows: 1 Transactions of the American Institute Mining Engineers, XVII, 1888, 1889, p. in. 54 THE NON-METALLIC MINERALS. Mining is done by means of galleries on two levels. There are 1 6 to 25 feet of earth above the salt deposit. The contour of the latter conforms nearly with that of the surface. The working shaft is 1 68 feet deep. The depth of the first level of floor is 90 feet; to the second, 70 feet farther. The remaining 8 feet are used for a dump. The galleries of the first level were run, on an average, 40 feet in width and 25 feet and upwards in height, leaving supporting pillars 40 feet in diameter. The galleries of the second level are run 80 feet in width and 45 feet in height, leaving supporting pillars 60 feet in diameter. The lower pillars are so left that the weight of the upper ones rests upon them in part, if not wholly, with a thickness of at least 25 feet of salt rock between. Galleries aggregating nearly i mile in length have been run on the upper level and some 700 feet on the lower. In running a gallery the first work is the " undercutting " on the level of the floor, of sufficient height to enable the miners to work with ease. The salt is then blasted down from the overhanging body. The yearly output is about 50,000 tons. The salt as it comes from the mine is dumped into corrugated cast-iron rolls, which crush it. Next it goes into revolving screens, which take out the coarser lumps for ''crushed salt" and let the fine stuff pass to the buhrstones. These grind the salt, and from them it goes to the pneumatic separators,, which take out the dust and separate the market salt into various grades. Taking the dust out is essential to the production of a salt that will not harden, since the fine particles of dust deliquesce readily, and on drying cement the coarse particles together. The drill used in the mine is what is known as the "Russian auger." It is turned by hand and forced by a screw of 12 threads per inch. The holes take cartridges ij inches in diameter. Two men will bore 75 feet of hole each work- ing-day of eight hours. Three-quarters of a pound of 18 per cent dynamite is used to the ton of salt mined. On the Colorado Desert the salt occurs in the form of a crust a foot or more in thickness, resting on a lake of shallow brine. This crust, which is covered with a thin layer of dust and sand blown over it from the surrounding desert, is cut away longitudinally, much HALIDES. 55 as ice is cut in the North. When loosened, the block, falling into the water beneath, is cleaned of its impurities, and is then thrown out on a platform to dry, after which it is ground and packed for market. In many parts of the arid West the salt is obtained merely by shoveling up the impure material deposited by the evaporation of salt lakes and marshes during seasons of drought. In this way is obtained a large share of the material used in chloridizing ores. In the preparation of salt from sea water, solar evaporation alone is relied upon nearly altogether. This method, like the next to be mentioned, depends for its efficiency upon the fact already noted that sea water holds in solution besides salt various other ingre- dients, which, owing to their varying degrees of solubility, are depos- ited at different stages of the concentration. In Barnstable County, Massachusetts, it was as follows : A series of wooden vats or tanks, with nearly vertical sides and about a foot in depth, is made from planks. These are set upon posts at different levels above the ground, and so arranged that the brine can be drawn from one to another by means of pipes. Into the first and highest of these tanks, known as the "long water room," the water is pumped di- rectly from the bay or artificial pond by means of windmills, and there allowed to stand for a period of about ten days, or until all the sediment it may carry is deposited. Thence it is run through pipes to the second tank, or " short water room," where it remains exposed to evaporation for two or three days longer, when it is drawn off into the third vat, or "pickle room," where it- stands until concen- tration has gone so far that the lime is deposited and a thin pellicle of salt begins to form on the surface. It is then run into the fourth and last vat, where the final evaporation takes .place and the salt itself crystallizes out. Care must be exercised, however, lest the evapora- tion proceed too far, in which case sulphate of soda (Glauber's salt) and other injurious substances will also be deposited, and the quality of the sodium chloride thereby be greatly deteriorated. As to the capabilities of works constructed as above, it may be said that during a dry season vats covering an area of 3,000 square feet would evaporate about 32,500 gallons of water, thus producing some 100 bushels of salt and 400 pounds of Glauber's salt. The moist climate of the Atlantic States, however, necessitates the roof- 56 THE NON-METALLIC MINERALS. ing of the vats in such a manner that they can be protected or exposed as desired, thereby greatly increasing the cost of the plant. Sundry parts of the Pacific coast, on the other hand, owing to their almost entire freedom from rains during a large part of the year, are pecu- liarly adapted for the manufacture by solar evaporation. Hence, while the works on the Atlantic coast have nearly all been discon- tinued, there has been a corresponding growth in the West, and particularly in the region about San Francisco Bay. The methods of procedure in the California works do not differ materially from that already given, excepting that no roofs are required over the vats, which are therefore made much larger. One of the principal establishments in Alameda County may be described as follows : The works are situated upon a low marsh, naturally cov- ered by high tides. This has been divided, by means of piles driven into the mud and by earth embankments, into a series of seven vats or reservoirs, all but the last of which are upon the natural surface of the ground that is, without wooden or other artificial bottoms. The entire area inclosed in the seven vats is about 600 acres, neces- sitating some 15 miles of levees. The season of manufacture lasts from May to October. At the beginning of the spring tides, which rise some 12 to 15 inches above the marsh level, the fifteen gates of reservoir No. i, comprising some 300 acres, are opened and the waters of the bay allowed to flow in. In this great artificial salt lake the water is allowed to stand until all the 'mud and filth have become precipitated, which usually requires some two weeks. Then, by means of pumps driven by windmills, the water is driven from reservoir to reservoir as concentration continues, till finally the salt crystallizes out in No. 7, and the bittern is pumped back into the bay. The annual product of the works above described is about 2,000 tons. A somewhat similar process is pursued in the manufacture of salt from inland lakes, as the Great Salt Lake, Utah. The following account of the method here employed is by Dr. J. E. Talmage: " The Inland Salt Company's gardens are situated near Garfield Beach, the most popular pleasure resort on the lake. In the method employed the water is pumped from the lake into ponds prepared for its reception and situated above the level of the lake surface. HALIDES. 57 The mother liquors flow off are returned to the lake, in fact when the evaporation has reached the proper stage. From the establishment of the works until 1883 the lake was close to the ponds; but, owing to the unusually high rate of evaporation attending the dry seasons of the immediate past, the water has receded, so that at present it has to be conveyed over 2,500 feet to the evaporating receptacles. This is effected by the aid of two centrifugal pumps, raising together 14,000 gallons of water per minute. The pumps throw the water to a height of 14 feet into a flume, through which it flows to the ponds. These are nine in number, and are arranged in series. In the first pond the mechanically suspended matters are left as sediment or scum, and the water passes into the second in a clear condition. The ponds cover upward of a thousand acres, and the drain channels leading from them aggregate nine miles in length. The pumping continues through May, June, and July. A fair idea of the rate of evaporation in the thirsty atmosphere of the Great Basin may be gained from contemplating the fact that to supply the volume of water disappearing from the ponds by evaporation requires the action of the pumps ten hours daily in June and July. This is equal to the carrying away of 8,400,000 gallons per day from the surface of the ponds. " The ' salt harvest ' begins in August, soon after the cessation of pumping, and continues till all is gathered, frequently extending into the spring months of the succeeding year. An average season yields a layer of salt 7 inches deep, which amount would be deposited from 49 inches of lake water. The density at which salt begins to deposit, as observed at the ponds and confirmed by laboratory experiments, is 1.2121, and that of the escaping mother liquors is 1.2345. The yield of salt is at the rate of 150 tons per inch per acre. The crop is gathered on horse cars, which run on movable tracks into the ponds. At the works the operations are simple and effective. A link-belt conveyor carries the coarse salt to the crusher; thence to the dryer, after which a sifting process is employed by which the salt is separated into table salt and dairy salt." l Owing to the depth below the surface of the salt beds in Ohio, 1 Science, XIV, 1889, p. 445. 58 THE NON-METALLIC MINERALS. Michigan, and other inland States, the material is never mined as in the cases first mentioned, but is pumped to the surface as a brine and there evaporated by artificial heat. In the Warsaw Valley region the beds lie from 800 to 2,500 feet below the surface, and are reached by wells. These are bored from 5^ to 8 inches in diameter and are cased with iron pipes down to the salt. Inside the first pipe is then introduced a second 2 inches in diameter, with perforations for a few feet at its lower end, and which extends nearly, if not quite, to the bottom. Fresh water is then allowed to run from the surface down between the two pipes. This dissolves the salt, and forms a strong brine which, being heavier, sinks to the bottom of the well and is pumped up through the smaller or inner tube. At Syracuse the wells are not sunk into the salt bed itself, but into an ancient gravel deposit which is saturated with the brine. Here the intro- duction of water from the surface is done away with. In* those cases, not at all uncommon, where the brine flows naturally to the surface in the form of a spring, pumping is of course dispensed with. The methods of evaporation vary somewhat in detail. In New York the brine is run in a continuous stream in large pans some 130 feet long by 20 feet wide and 18 inches deep. As it evaporates the salt is deposited on the bottom, and, by means of long-handled scrapers, is drawn on the sloping sides of the pan. Here it is allowed to drain, and is afterwards taken to the storage bins for packing or grinding. 1 Salt thus produced, it should be noticed, is never so coarse as the so-called rock salt, or that which has formed by natural evaporation. In Michigan the brine from the wells is first stored in cisterns, whence it is drawn off into large shallow pans, known technically as "settlers," where it is heated by means of steam pipes to a temperature of 175, until' the point of saturation is reached. It is then drawn into a second series of pans, called "grainers," where it is heated to a temperature of 185, until crystallization takes place. (Plate III.) The strength of brines, and therefore the quantity of water that must be evaporated to produce a given quantity of salt, varies 1 For details, see Salt and Gypsum Industries of New York, by Dr. F. J. H. Mer- rill, Bulletin No. n, New York State Museum, 1893. PLATE III. Views of Brine Evaporating Tanks at Syracuse, New York. [U. S. National Museum.] MAUDES. 59 greatly in different localities. At Syracuse the brine contains 15.35 per cent of salt; at the Saginaw Valley, 17.91 per cent; at Saltville, Virginia, 25.97 per cent; while Salt Lake contains n.86 per cent, and the waters of San Francisco Bay but 2.37 per cent. The amount of impurities depends on the care exercised in process of manufacture, rapid boiling giving less satisfactory results than slower methods. The Syracuse salt has been found to contain 98.52 per cent sodium chloride; California Bay salt 98.43 per cent and 99.44 per cent; and Petite Anse 99.88 per cent. The impurities in these cases are nearly altogether chlorides and sulphates of lime and magnesia. The Cheshire (England) salt beds are worked both by mining as rock salt and by pumping the brine. Formerly both upper and lower beds were mined, but flooding and falling in of the roofs caused the work to be discontinued on the upper beds. That now mined as rock salt comes wholly from the lower bed, and ' being impure is used mainly for agricultural purposes. At Wieliczka the salt is likewise mined from galleries resembling in a general way those of a coal mine. These, according to Brehm, 1 begin at a depth of about 95 meters, forming several levels connected by stairways, the lowermost gallery being at a depth of 312 meters, or some 50 meters below sea level. These galleries have a total length of some 680 kilometers. They are connected with one another by means of "onze puits," of which seven are utilized for hoisting purposes. The work goes on continually night and day the year through. The salt is cut out in the form of blocks, leaving huge chambers, the roof being sustained by means of large columns of salt left standing. The temperature within these chambers is very uniform, varying only between 10 and 15 C. The air is dry and healthful. The miners hew out of the salt statues of the saints, pyramids, and chandeliers, where they can place 300 lights. One chamber, called the Chapel of St. Antoine, with its altar, statues, columns, etc., is still in a condition of perfect preservation after a lapse of two centuries. The statements to the effect that the work- men, and indeed entire families, pass a good share of their lives in these mines, almost never coming to the surface, is stated by Brehm 1 Marveilles De La Nature. La Terre, etc., p. 315. 60 THE NON-METALLIC MINERALS. to be wholly erroneous. In reality, all the workers leave daily, only the horse remaining below. The output of salt in the United States for 1900 amounted to- upwards of 20,000,000 barrels of 280 pounds each, of which 85 per cent was from mines and wells in New York, Michigan, and Kansas. The annual output for the entire world amounts to upwards of 10,000,000 metric tons. Uses. The principal uses of salt have always been for culinary and preservative purposes. Aside from these, it is also used in certain metallurgical processes and in chemical manufacture, as in the preparation of the so-called soda ash (sodium carbonate), used in glass making, soap making, bleaching, etc., and in the preparation of sodium salts in general. Clear, transparent salt has been utilized in a few instances in optical and other research work. 2. ELUORITE. This is a calcium fluoride, CaF 2 , = fluorine, 48.9 per cent ; calcium, 51.1 per cent. The most striking features of this mineral are its cubic crystallization, octahedral cleavage, and fine green, yellow, purple, violet, and sky-blue colors. White and red-brown varieties are also known. The mineral is translucent to transparent, and of a hardness somewhat greater than calcite (4 of Dana's scale). Occurrence. The mineral occurs, as a rule, in veins, in gneiss, the schists, limestones, and sandstones. It is also a common gangue of metallic ores, particularly those of lead and tin. The principal American sources are Rosiclare, in southern Illi- nois, and on the opposite side of the Ohio River, in Kentucky, though deposits have been reported in Smith, Trousdale, and Wilson coun- ties in Tennessee, and near Yuma, Arizona. At Rosiclare the fluorspar occurs in what are regarded as true fissure veins in the Lower Carboniferous limestone, varying from four to forty or more feet in width. The original portion of the vein was, however, much smaller,, the crevices having been enlarged by circulating waters, and the present great width being due to a par- tial replacement of the limestone. On the hanging-wall side of the vein the fluorspar contents arc not pure, and often contain fragments of the country rock. .There is also a gradation from the solid fluorspar, so there is no sharp MAUDES. 6* contact of the vein. Near the foot-wall the fluorspar is often found in solid masses from two to twelve feet in thickness. With the fluorspar there is nearly always associated calcspar, galena, and sphalerite, and occasionally pyrite, chalcopyrite, and barite. The depth to which the deposits extend has not been determined, but they have been worked to a depth of 200 feet without any appar- ent diminution in width of the vein, and Emmons 1 regards it as reasonable to assume that they will extend as far down as the Trenton and Cambrian limestone. In both Illinois and Kentucky the deposits are worked by means of shafts and drifts. As taken from the mine, the mineral is, in some cases, concentrated by a hand-cobbing machine and by the use of water-jigs, though in some cases it is shipped directly from the mine after having been simply washed. In a number of cases the lead and zinc ores commingled with the flourite are saved as by-products. Illinois and Kentucky are the principal sources of fluorspar as* at present mined in America. The actual amount there existing is probably more than sufficient to supply the demand for many years to come. The average output at date of writing is about 20,000 tons, valued at from $5 to $6 per ton. Uses. The material is used mainly as a flux for iron, in the manufacture of opalescent glass, and for the production of hydro- fluoric acid. , 3. CRYOLITE. Composition. Na 3 AlF 6 , = aluminum, 12.8 per cent; sodium, 32.8 per cent; fluorine, 54.4 per cent. The mineral is, as a rule, of snow- white color, though sometimes reddish or brownish, rarely black, and coarsely crystalline granular, translucent to subtransparent. It has a hardness of 2.5 ; specific gravity of 2.9 to 3, and in thin splinters may be melted in the flame of a candle. The name is from the Greek word xpvos, ice, in allusion to its translucency and ice-like appearance. Mode of occurrence. Cryolite occurs, as a secondary product, in the form of veins. It is rarely found in sufficient abundance to> 1 Transactions of the American Institute of Mining Engineers, XXI, 1893, p. 31, 62 THE NON-METALLIC MINERALS. be of commercial value, the supply at present coming almost wholly from Evigtok in South Greenland. The country rock here is said to be granite, and the vein as described in 1866 l was 150 feet in greatest breadth, and was exposed for a distance of 600 feet. The principal mineral of the vein was cryolite, but quartz, siderite, galena, and chalcopyrite were constant accompaniments, irregularly dis- tributed through the mass. In 1890 the mine as worked was de- scribed as a hole in the ground, elliptical in shape, 450 feet long by 150 feet wide, the pit being some 100 feet deep. The drills had penetrated 150 feet deeper and found cryolite all the way. John- strup, as quoted by Dana, 2 describes the cryolite as " limited to the granite; he distinguishes a central and a peripheral part; the former has an extent of 500 feet in length and i,oco feet in breadth, and consists of cryolite chiefly, with quartz, siderite, galena, sphalerite, pyrite, chalcopyrite, and wolframite irregularly scattered through it. The peripheral portion forms a zone about the central mass of cryolite ; the chief minerals are quartz, feldspar, and ivigtite, also fluorite, cassiterite, molybdenite,, arsenopyrite, columbite. Its inner limit is rather sharply defined, though there intervenes a breccia-like portion ' consisting of the minerals of the outer zone inclosed in cryolite; beyond this it passes into the surrounding granite without distinct boundary." Cryolite in limited quantity occurs at the southern base of Pike's Peak, in Colorado, and north and west of St. Peter's Dome. It is found in vein-like masses of quartz and microcline embedded in granite. Uses. Until within a few years the material has been utilized only in the manufacture of soda, and sodium and aluminum salts, and to a small extent in the manufacture of glass and porcelain ware. It is also used in the electrolytic processes of extracting aluminum from its ores, as now practiced. The principal works utilizing the Greenland cryolite in chemical manufacture are, at time of writing, those of the Pennsylvania Salt Manufacturing Company at Natrona, Pennsylvania. From 5,000 to 10,000 tons are imported annually, valued at about $12 per ton. 1 Paul Quale, Report of Smithsonian Institution, 1866, p. 398. 2 System of Mineralogy, 1892, p. 167. OXIDES. IV. OXIDES. I. SILICA. Quartz. The mineral quartz, easily recognized by its insolu- bility in acids, glassy appearance, lack of cleavage, and hardness, which is such that it readily scratches glass, is one of the most common and widely disseminated of minerals. Chemically it is pure silica, of the formula SiO 2 . It crystallizes in the hexagonal system with beautiful terminations, and is one of the most attractive of minerals for the amateur collector. The common form is, however, massive, occurring in veins in the older crystalline rocks. Common sand is usually composed mainly of quartzose grains which, owing to their hardness and resistance to atmospheric chemical agencies, have withstood disintegration to the very last. The terms rose, milky, and smoky are applied to quartzes which differ from the ordinary type only in tint, as indicated. Chalcedony is the name given to a somewhat horn-like, translucent or transparent form of silica occurring only as a secondary constituent in veins, or isolated concretionary masses, and in cavities in other rocks. Agate is a banded variety of chalcedony. The true onyx is similar to agate, except that the bands or layers of different colors lie in even planes. Jasper is a ferruginous, opaque chalcedony, sometimes used for ornamental purposes. Opal is an amorphous form of silica, containing somewhat variable amounts of water. Quartz occurs as an essential constituent of granite, gneiss, mica schist, quartz porphyry, and liparite, and also as a secondary constituent in the form of veins, filling joints and cavities in rocks of all kinds and all ages. Uses. The finer clear grades of quartz are used to some extent for spectacle lenses and optical work, as well as in cheap jewelry. Its main value is, however, for abrading purposes, either as quartz sand or as sandpaper, and in the manufacture of pottery. For abrading purposes it is crushed and bolted, like emery and corun- dum, and brings a price barely sufficient to cover cost of handling and transportation. There is a remarkable variation in quartz as relates to its suitability for abrasive purposes, some varieties on THE NON-METALLIC MINERALS. crushing giving rise to sharp, splintery fragments possessing a high degree of cutting or abrading power, while others yield sands that are dull and of less value. As a rule the clear, glassy quartz will yield a sharper sand than the opaque and milky forms. Pure quartz sand is also of value for glass-making, and ground quartz to some extent as a " filler" in paints, and as a scouring material in soaps. The following analyses show the composition of some glass sands from (I) Clearfield, and (II) Lewistown, Penn- sylvania : Constituents. I. II. Silica, 00 70 08 84. Alumina . ...... O.I2 o 17 Iron oxides O.OI4 O. 34 Lime o 8 Traces. Ignition O 2 T. 100.724 99- 5 8 Flint is a chalcedonic variety of silica found in irregular nodular forms in beds of Cretaceous chalk. These nodules break with a conchoidal fracture and interiorly are brownish to black in color. By the aboriginal races the flints were utilized for the manufacture of knives and general cutting implements. Later they were used in the manufacture of gun-flints and the "flint and steel" for producing fire. At present they are used to some extent in the manufacture of porcelain, being calcined and ground to mix with the clay and give body to the ware. In this country the same purpose is accomplished by the use of quartz. Small round nodules of flint from Dieppe, France, are said to be used in the Trenton (New Jersey) pottery works for grinding clay by being placed in revolving vats of water and kaolin. All the flint now used in this country is imported either as ballast or as an accidental constituent of chalk. As the material is worth but from $i to $2 a ton delivered at Trenton, it may be readily understood that transportation is a rather serious item to be considered in developing home resources. According to Mr. R. T. Hill, nodules of black flint occur in enor- mous quantities in the chalky limestones the Caprina limestones of Texas. Numerous localities are mentioned, the most accessible being near Austin, on the banks of the Colorado River. OF THE UNIVERSITY OF OXIDES. 65 Buhrstone, or burrstone, is the name given to a variety of chalcedonic silica, quite cavernous^ and of a white to gray or slightly yellowish color. The cavernous structure is frequently due to the dissolving out of calcareous fossils. The rock is of chemical origin that is, results from the precipitation of silica from solution, and presumably through the action of organic matter. In France the material occurs alternating with other unaltered Tertiary strata in the Paris basin. It is also reported in Eocene strata in South America, and in Burke and Screven counties along the Savannah River in southern Georgia in the United States. The toughness of the rock, together with the numerous cavities, impart a sharp cutting power such as renders them admirably adapted for millstones, and in years past material for this purpose has been sent out from French sources all over the civilized world. Tripoli is the commercial name given to a peculiar porous rock regarded as a decomposed chert associated with the Lower Car- boniferous limestones of southwest Missouri. The rock is of a cream- white or slight pink cast, fine grained and homogeneous, with a distinct gritty feel, and, though soft, sufficiently tenacious to permit of its being used in the form of thin disks of considerable size for filtering purposes. According to Hovey 1 the deposit is known to underlie between 80 and 100 acres of land, in the form of a rude ellipse, with its longer diameter approximately north and south. From numerous prospect holes and borings it has been shown to have an average thickness of 15 feet, the main quarry of the present company showing a thickness of 8 feet. The following section is given from a well sunk in the northern part of the area: Feet. Earth o to 4 Tripoli 4 20 Stiff red clay 20 21$ Mrxed chert, clay, and ocher 2i 40 Cherty limestone 40 93 Cherty limestone bearing galena 93 103 Limestone 103 128 Limestone bearing sphalerite and galena 128 136 Soft magnesian limestone 136 173 1 Scientific American Supplement, July 28, 1894, p. 15487. 66 THE NON-METALLIC MINERALS. The tripoli is everywhere underlain by a relatively thin bed of stiff red clay, and also traversed in every direction by seams of the same material from i to 2 inches thick. These seams and other joints divide the rock into masses which vary in size up to 30 inches or more in diameter. Microscopic examinations as given by Hovey show the rock to contain no traces of organic remains, but to be made up of faintly doubly refracting chalcedonic particles from o.oi to 0.03 millimeter in diameter. The chemical composition, as shown from analysis by Prof. W. H. Seaman, is as follows: Silica (SiO a ) 98.100 Alumina (A1 2 O 3 ) 0.240 Iron oxide (FeO and Fe 2 O 3 ) 0.270 Lime (CaO) 0.184 Soda (Na 2 O) 0.230 Water (ignition) 1.160 Organic matter 0.008 100.192 Silica soluble in a 10 per cent solution of caustic soda on boiling three hours, 7.28 per cent. Aside from its use as a filter the rock is crushed between buhr- stones, bolted, and used as a polishing powder. To a small extent it has been used in the form of thin slabs for blotting purposes, for which it answers admirably, owing to its high absorptive property, but is somewhat objectionable on account of its dusty character. The view (Plate IV) shows the character of a quarry of this material as now worked by the American Tripoli Company at Seneca, in Newton County. Diatomaceous or infusorial earth, as it is sometimes wrongly called, is, when pure, a soft, pulverulent material, somewhat resem- bling chalk or kaolin in its physical properties, and of a white or yellowish or gray color. Chemically it is a variety of opal (see analyses on p. 68). Origin and occurrence of deposits. Certain aquatic forms of plant life known as diatoms, which are of microscopic dimensions only, have the power of secreting silica in the same manner as mollusks OXIDES. 67 secrete carbonate of lime, forming thus their tests or shells. On the death of the plant the siliceous tests are left to accumulate on the bottom of the lakes, ponds, and pools in which they lived, forming in time beds of very considerable thickness, which, however, when compared with other rocks of the earth's crust, are really of very insignificant proportions. Like many other low organisms the diatoms can adapt themselves to a wide range of conditions. They are wholly aquatic, but live in salt and fresh water and under widely varying conditions of depth and temperature. They may be found in living forms in almost any body of comparatively quiet water in the United States. The exploring steamer Challenger dredged them up in the Atlantic from depths varying from 1,260 to 1,975 fathoms, and from latitudes well toward the Antarctic Circle. Mr. Walter Weed, of the U. S. Geological Survey, has recently reported them as living in abundance in the warm marshes of the Yellow- stone National Park, while Dr. Blake reported finding over 50 species in a spring in the Pueblo Valley, Nevada, which showed a tem- perature of 163 F. Although beds of diatomaceous earth are still in process of forma- tion, and in times past have been formed at various epochs, the Tertiary period appears for some reason to have been peculiarly fitted for the growth of these organisms, and all of the known beds of any importance, both in America and foreign countries, are of Tertiary Age. The best known of the foreign deposits is that of Bilin, in Bohemia. This is some 14 feet in thickness. When it is borne in mind that, according to the calculations of Ehrenberg, every cubic inch of this contains not less than 40,000,000 independent shells, one stands aghast at the mere thought of the myriads of these little forms which such a bed represents. Some of the deposits in the United States are, however, considerably larger than this. What is commonly known as the Richmond bed extends from Herring Bay, on the Chesapeake, Maryland, to Petersburg, Virginia, and perhaps beyond. This is in some places not less than 30 feet in thickness, though very impure. Near Drakesville, in New Jersey, there occurs a smaller deposit, covering only some 3 acres of territory to a depth of from i to 3 feet. Some of the largest deposits known are in the West. Near Socorro, in New Mexico, there is stated to 68 THE NON-METALLIC MINERALS. be a deposit of fine quality which crops out in a single section for a distance of 1,500 feet and some 6 feet in thickness. Geologists of the fortieth-parallel survey reported abundant de- posits in Nevada, one of which showed in the railroad cutting west of Reno a thickness not less than 300 feet, and of a pure white, pale buff, or canary-yellow color. Along the Pitt River, in California, there is stated to be a bed extending not less than 16 miles, and in some places over 300 feet thick (see Plate V). Near Linkville, Kla- math County, Oregon, there occurs a deposit which has been traced for a distance of 10 miles, and shows along the Lost River a thick- ness of 40 feet. Beds are known also to occur in Idaho, near Seattle, in Washington, and doubtless many more yet remain to be discovered. A deposit of unknown extent, pure white color, and almost pulp- like consistency, has been worked in South Beddington, Maine. Others of less purity occur near South Framingham, Massachusetts, Lake Umbagog, New Hampshire, at Whitehead Lake, Herkimer County, New York, and at Grand Manan, New Brunswick. Chemical composition. As already intimated, this earth is of a siliceous nature, and samples from widely separated localities show remarkable uniformity in composition. Of the following analyses, No. I is from Lake Umbagog, New Hampshire, No. II from Morris County, New Jersey, and No. Ill from Pope's Creek, in Maryland. As will be noted, the silica percentage is nearly the same in all. Constituents. I. II. III. Silica 80 reference. 3 American Jour, of Science, Vol. IV, 1894, p. 42. PLATE VIII. Microstructure of Emery. [U. S. National Museum. OXIDES. 77 Geologically emery, like corundum, belongs mainly to the older crystalline rocks. In Asia Minor it occurs in angular or rounded masses from the size of a pea to those of several tons weight, embedded in a blue-gray or white crystalline limestone, which overlies mica- ceous or hornblendic schists, gneisses, and granites. Superficial decomposition has, as a rule, removed more or less of the more soluble portions of the limestone, leaving the emery nodules in a red ferruginous soil. With the emery are associated other aluminous minerals as mentioned below. According to Tschermak 1 the Naxos emery occurs mostly in the form of an iron-gray, scaly to schistose, rarely massive, aggregate consisting essentially of magnetite and corundum, the latter mineral being in excess. In addition to these two minerals occur hematite and limonite, as alteration products of the magnetite. Margarite,. muscovite, biotite, tourmaline, chloritoid, diaspore, disthene, stauro- lite, and rutile occur as common accessories; rarely are found spinel, vesuvianite, and pyrite. Under the microscope he finds the emery rock to show the corundum in rounded granules and some- times well-defined crystals with hexagonal outlines, particularly in cases where single individuals are embedded in the iron ores. (Plate VIII, Fig. 2.) In many cases, as in the emery of Krenino and Pesulas, the granules are partially colored blue by a pigment some- times irregularly and sometimes zonally distributed. The corundum grains, which vary in size between 0.05 mm. and 0.52 mm. (averaging about 0.22 mm.), are very rich in inclosures of the iron ores, largely magnetite in the form of small, rounded granules. The quantity of these is so great as at times to render the mineral quite opaque, though at times of such dust-like fineness as to be translucent and of a brownish color. The larger corundums are often injected with elongated, parallel-lying clusters or groups of the iron ores, as shown in Fig. 3, from Tschermak' s paper, and are surrounded by borders of very minute zircons. The iron ore, as noted above, is principally magnetite, but which, by hydration and oxidation, has given rise to abundant limonite. The magnetites are in the form of rounded granules and dust-like particles, and also at times in 1 Mineralogische und Petrographische Mittheilungen, XIV, 1894, p. 313. 3 s THE NON-METALLIC MINERALS. well-defined octahedrons. In their turn the magnetites also in- close particles of corundum very much as the metallic iron of meteorites of the pallasite group inclose the olivines, and as shown in Plate VIII, Fig. 4. The following account of these deposits and the method of work- ing is by A. Gobantz : l Naxos, the largest of the Cyclades Islands, is remarkable as being one of the few localities in the world producing emery on a large scale; the deposits, which are of an irregularly bedded or lenticular form, being mostly concentrated on the mountains at the northern end of the islands, the most important ones being in the immediate vicinity of the village of Bothris. The island is principally made up of Archaean rocks, divisible into gneiss and schist formations, the latter consisting of mica schists alternating with crystalline lime- stones. The lenticular masses of emery, which are quite variable in size, ranging in length from a few feet to upward of 100 yards and in maximum thickness from 5 to 50 yards, are closely asso- ciated with the limestones, and, as they follow their undulations, they vary greatly in position, lying at all kinds of slope, from hori- zontal to nearly vertical. Seventeen different deposits have been discovered and worked at different times. These range over con- siderable heights from 180 to 700 meters above sea-level, the largest working, that of Malia, being one of the lowest. This important deposit covers an area of more than 30,000 square meters, extending for about 500 meters in length with a height of more than 50 meters. This was worked during the Turkish occupation, and it has supplied fully one-half of all the emery exported since the formation of the Greek Kingdom. The highest quality of mineral is obtained from two comparatively thin but extensive deposits at Aspalanthropo and Kakoryakos, which are 435 meters above the sea-level. The mineral is stratified in thin bands from i to 2 feet in thickness, crossed by two other systems of divisional planes, so that it breaks into nearly cubical blocks in the working. The floor of the deposit is invariably 1 Oesterreichische Zeitschrift fiir Berg- und Hiittenwesen, XLII, p. 143. Abstract in the Minutes and Proceedings of the Institute of Civil Engineers, CXVII, pp. 466- 468. OXIDES. 79 crystalline limestone, and the roof a loosely crystalline dolomite covered by mica schist. The underlying limestones are often penetrated by dikes of tourmaline granite, which probably have some intimate connection with the origin of the emery beds above them. " Mineralogically emery is a compact mixture of blue corundum and magnetic iron ore, its value as an abrasive material increasing with the proportion of the former constituent. This proportion has, however, been usually much overestimated. Seven samples collected by the author have been examined at the Technical High School in Vienna, and found to contain from 60 to 66 per cent of alumina. The average composition may be considered to be two-thirds corun- dum, the remainder being magnetite and silica in the proportion of about 2 to i, with some carbonate of lime. " The working of the deposits is conducted in an extremely primi- tive fashion. During the period of Turkish rule the exclusive right of emery mining was given to two villages, and this rule has prevailed up to the present time, no Greek Government having ventured to break down the monopoly. These privileged workmen are about 600 in number, and have the right of working the mineral wherever and in what manner they may think best. The produce is taken over by the Government official at the rate of about 3 123. for 50 cwts. The rock is exclusively broken by fire-setting. A piece of ground, about 5 feet broad and the same height, is cleared from loose material, and a pile of brushwood heaped against it and lighted. This burns out in about twenty-four or thirty hours, when water is thrown upon the heated rock to chill it and develop fractures along the secondary divisional planes in the mass of emery, and so facili- tate the breaking up and removal of the material. Sometimes a crack is opened out by inserting a dynamite cartridge, but the regular use of explosives is impossible, owing to the hardness of the mineral, which can not be bored with steel tools. Only the larger lumps are carried -down to the shipping place, the smaller sizes, up to pieces as large as the fist, being left on the ground. " As most of the suitable places for fire-setting at the surface have been worked out, attempts have been made to follow the deposits underground, but none of these have been carried to any depth, 8o THE NON-METALLIC MINERALS. partly on account of the suffocating smoke of the fires, rendering continuous work difficult; but more particularly from the danger- ous character of the loose dolomite roof, which is responsible for many fatal accidents from falls annually. These might, of course, be prevented by the judicious use of timber or masonry to support the roof, but this appears to be beyond the skill of the native miners. " The rapid exhaustion of the forests in the neighborhood of the mines, owing to the heavy consumption of fuel in fire-setting, has been a cause of anxiety to the Government for some years past, and competent experts have been employed to suggest new methods of working. These have been tolerably unanimous in recommending the institution of systematic quarry workings, using diamond boring machines and powerful explosives for winning the mineral, and the construction of wire-rope ways and jetties for improving the methods of conveyance and shipping ; but as funds for these improvements, owing to the disastrous condition of the national finances, are not obtainable, the primitive method of working still continues. Mean- while the competition of the mines in Asia Minor has become so intense that the export of emery from Naxos has almost entirely ceased for a year past." The principal deposit of emery at present worked in the United States occurs on what are known as North and South Mountains, near Chester, in Hampden County, Massachusetts. These deposits were first described by Dr. C. T. Jackson (in 1865) and developed by Dr. H. S. Lucas, the material being at first regarded as mainly magnetite and worked as an iron ore. The vicissitudes of the operations here, like those of the chromite deposits near Baltimore, form one of the interesting chapters in the history of mining operations in the United States, but which can not be now touched upon. The deposits have been frequently described, as noted in the bibliography, the facts which are here given being derived mainly from the recent works of B. K. Emerson and J. H. Pratt. The country rock is schistose epidotic-amphibolite of doubtful origin, but which Pratt thinks may be an altered eruptive. The emery-bearing veins conform in a general way with the winding of the schist, and OXIDES. 81 have a strike of approximately north 20 east, south 20 west, dipping to the eastward at an angle of some 70. As first shown, where cut by the Westfield River, the vein is very narrow, but widens rapidly to the north, attaining a width of 17 feet, of which some 10 feet are FIG. ii. Map showing location of emery deposits at Chester, Massachusetts. [U. S. Geological Survey.] emery, the remainder being mainly magnetite. The vein, or bed, cuts through both North and South Mountains, and has been traced a distance of some 5 miles, though the emery is not continuous for the entire distance. It can, however, be traced by means of streaks of chlorite (corundophillite) which almost invariably accom- pany it. Other characteristic associates are the above noted mar- garite and magnetite, talc, and black tourmaline, the vein material itself being described as a chloritic magnetite containing in abundance bronze-colored grains of emery and, along the borders of the thicker portion of the main vein and of the eastern vein, a considerable 82 THE NON-METALLIC MINERALS. quantity of brown-black tourmaline in delicate stel- late forms The part of the vein rich in emery shows the material in the form of a dark gray, nearly black massive rock, throughout which the co- rundum is disseminated in the form of small crystals, sometimes 5 to 15 milli- meters in diameter and of a rich bronze color. Six mines have from time to time been opened on this deposit, as shown in Fig. ii. At the Melvin Mine the vein varies from 6 to 1 6 feet in width. A cross-section of the Old Mine is given in Fig. 12. The limits of the deposit as given by Emerson are: Length, 4 miles; depth, 750 feet (above the level of the brook), and with an average width of 4 feet. The origin of this ore has, naturally, been a mat- ter of some speculation. Emerson regards it as most probable that the emery- magnetite material was originally a deposit of li- moni e which was formed by the replacement of lime- stone, and into which alu- OXIDES. 83 mina was carried by infiltrating solutions and deposited as allophane and gibbsite, ultimately altered into corundum and magnetite by metamorphism. Pratt, on the other hand, regards the amphibolite as probably an altered eruptive rock, and argues that the magnetite and corundum are both segregations of basic materials from the igneous magma, i.e., are products of magmatic differentiation. In New York State emery deposits have been found associated with the norite rocks in Westchester County, where they have been described by Dr. G. H. Williams. 1 The emery here is regarded by the various authorities as being a product of magmatic differ- entiation. Sources. The chief commercial sources of emery are those of Gu- much-dagh, between Ephesus and the ancient Tralles; Kulah, and near the river Hermes in Asia Minor; and the island of Naxos, whence it is quarried and shipped from Smyrna, in part as ballast, to all parts of the world. The chief commercial source in the United States, or indeed, in North America, is Chester, Massachusetts, as above noted. The island of Naxos is stated to have for several centuries furnished almost exclusively the emery used in the arts, the material being chiefly obtained from loose masses in the soil. The mining at Kulah and Gumuch-dagh was begun about 1847, and at Nicaria in 1850. The emery vein at Chester, Massachusetts, was discovered by Dr. H. S. Lucas in 1863, and described by Dr. C. T. Jackson in 1864. In preparing for use, the mineral, after being dug from the soil or blasted from the parent ledge, is pulverized and bolted in various grades, from the finest flour to a coarse sand, the excess of magnetite, where such exists, being extracted by means of an electromagnet. The commercial prices vary according to grade from 3 to 10 cents a pound. At the end of the last century the price of the Eastern emery is given at from $40 to $50 a ton. About 1835 an English monopoly controlled the right of mining, and the price rose in 1847 to as high as $140 a ton. Uses. The chief uses of emery and corundum, as is well known, are in the form of powder by plate-glass manufacturers, lapidaries, 1 American Journal of Science, Vol. XXXIII, 1887, pp. 135-191. 84 THE NON-METALLIC MINERALS. and stone workers; as emery paper, or in the form of solid disks made from the crushed and bolted mineral and cement, known commercially as emery wheels. The great toughness and superior cutting power of these wheels render them of service in grinding glass, metals, and other hard substances, where the natural stone is quite inefficient. (See further under Grind- and Whetstones, p. 388.) BIBLIOGRAPHY OF CORUNDUM AND EMERY. JOHN DICKSON. Notes. American Journal of Science, III, 1821, pp. 4, 229. J. LAWRENCE SMITH. Memoir on Emery First part On the Geology and Miner- alogy of Emery, from observations made in Asia Minor. American Journal of Science, X, 1850, p. 354. Memoir on Emery Second part On the Minerals associated with Emery. American Journal of Science, XI, 1851, p. 53. WILLIAM P. BLAKE. Corundum in Crystallized Limestone at Vernon, Sussex County, New Jersey. American Journal of Science, XIII, 1852, p. 116. CHARLES T. JACKSON. Discovery of Emery in Chester, Hampden County, Massa- chusetts. Proceedings of the Boston Society of Natural History, X, 1864, p. 84. American Journal of Science, XXXIX, 1865, p. 87. CHARLES U. SHEPARD. A Description of the Emery Mine of Chester, Hampden County, Massachusetts. Pamphlet, 16 pp., London, 1865. J. LAWRENCE SMITH. On the Emery Mine of Chester, Hampden County, Massachu- setts. % American Journal of Science, XLII, 1866, pp. 83-93. Original Researches in Mineralogy and Chemistry, 1884, p. in. C. W. JENKS. Corundum of North Carolina. American Journal of Science, III, 1872, p. 301. CHARLES U. SHEPARD. On the Corundum Region of North Carolina and Georgia. American Journal of Science, IV, 1872, pp. 109 and 175. FREDERICK A. GENTH. Corundum, its Alterations and Associated Minerals. Proceedings of the American Philosophical Society, XIII, 1873, P- 361. C. W. JENKS. Note on the occurrence of Sapphires and Rubies in situ with Corun- dum, at the Culsagee Mine, Macon County, North Carolina. Quarterly Journal of the Geological Society, XXX, 1874, p. 303. W. C. KERR. Corundum of North Carolina. Geological Survey of North Carolina, I, Appendix C, 1875, p. 64. C. D. SMITH. Corundum and its Associate Rocks. Geological Survey of North Carolina, I, Appendix D, 1875, pp. 91-97. R. W. RAYMOND. The Jenks Corundum Mine, Macon County, North Carolina. Transactions of the American Institute of Mining Engineers, VII, 1878, p. 83. OXIDES 85 J. WLLCOX. Corundum in North Carolina. Proceedings, Academy of Natural Sciences, Philadelphia, XXX, 1878, p. 223. F. A. GENTH. The so-called Emery-ore from Chelsea, Bethel Township, Delaware County, Pennsylvania. Proceedings, Academy of Natural Sciences, Philadelphia, XXXII, 1880, p. 311. C. D. SMITH. Corundum. Geological Survey of North Carolina, II, 1881, p. 42. F. A. GENTH. Contributions to Mineralogy. Proceedings of the American Philosophical Society, XX, 1882. A. A. JULIEN. The Dunyte Beds of North Carolina. Proceedings of the Boston Society Natural History, XXII, 1882, p. 141. T. M. CHATARD. Corundum and Emery. Mineral Resources of the United States, 1883-84, p. 714. The Gneiss-Dunyte Contacts of Corundum Hill, North Carolina, in relation to the Origin of Corundum. Bulletin No. 42, U. S. Geological Survey, 1887, p. 45. G. H. WILLIAMS. Norites of the "Cortlandt Series." American Journal of Science, XXXIII, 1887, p. 194. F. A. GENTH. Contributions to Mineralogy. American Journal of Science, XXXIX, 1890, p. 47. Emery Mines in Greece. Engineering and Mining Journal, L, 1890, p. 273. A. GOBAUTZ. The Emery Deposits of Naxos. Engineering and Mining Journal, LVIII, 1894, p. 294. FRANCIS P. KING. Corundum Deposits of Georgia. Bulletin No. 2, Geological Survey of Georgia, 1894, 133 pp. T. D. PARET. Emery and Other Abrasives. Journal of the Franklin Institute, CXXXVII, 1894, pp. 353, 421. J. C. TRAUTWINE. Corundum with Diaspore, Culsagee Mine, North Carolina. Journal of the Franklin Institute, XCIV, p. 7. J. VOLNEY LEWIS. Corundum of the Appalachian Crystalline Belt. Transactions of the American Institute of Mining Engineers, XXV, 1895, p. 852,. Valuable Discover)' of Corundum. Canadian Mining Review, XV, 1896, p. 230. The Corundum Lands of Ontario. Canadian Mining Review, XVII, 1898, p. 192. Corundum in Ontario. Engineering and Mining Journal, LXVI, 1898, p. 303. A. M. STONE. Corundum Mining in North Carolina. Engineering and Mining Journal, LXV, 1898, p. 490. B. K. EMERSON. Monograph, XXIX, U. S. Geological Survey, 1898, p. 117. J. H. PRATT. Bulletin No. 180, U. S. Geological Survey, 1901. 86 THE NON-METALLIC MINERALS. BAUXITE. Composition. A1 2 O 3 .2H 2 O,= alumina, 73.9 per cent; water, 26.1 per cent. Commonly impure through the presence of iron oxides, silica, lime, and magnesia. Color, white or gray when pure, but FIG. 13. Pisolitic bauxite. Bartow, Georgia. [U. S. National Museum.] yellowish, brown, or red through impurities. Specific gravity, 2.55; structure, massive, or earthy and clay-like. According to Hayes * the bauxites of the Southern United States show considerable variety in physical appearance, though generally having a pronounced pisolitic structure. " The individual pisolites vary in size from a 1 The Geological Relations of the Southern Appalachian Bauxite Deposits. Trans- actions of the American Institute of Mining Engineers, XXIV, 1894, pp. 250-251. OXIDES. > fraction of a millimeter to 3 or 4 centimeters in diameter, although most commonly the diameter is from 3 to 5 millimeters. The matrix in which they are embedded is generally more compact and also lighter in color. The larger pisolites are composed of numerous concentric shells, separated by less compact substance or even open cavities, and their interior portions readily crumble to a soft powder. "In thin sections the ore is seen to be made up of amorphous flocculent grains, and the various structures which it exhibits are produced by the arrangement and degree of compactness of these grains. The matrix in which the pisolites are embedded may be composed of this flocculent material segregated in an irregularly globular form or in compact oolites, with sharply denned outlines. Or both forms may be present, the compact oolites being embedded in a matrix composed of the less definite bodies- In some cases the interstices between the oolites are filled either wholly or in part with silica, apparently a secondary deposition. "The pisolites also show considerable diversity in structure. In some cases they are composed of exactly the same flocculent grains as the surrounding matrix, from which they are separated by a thin shell of slightly denser material. This sometimes shows a number of sharply defined concentric rings, and is then distinctly separated from the matrix and the interior portion of the pisolite. The latter is also sometimes composed of imperfectly defined globular masses, and in other cases of compact, uniform, and but slightly granular substance. It is always filled with cracks, which are regularly radial and concentric, in proportion as the interior substance has a uniform texture. Branching from the larger cracks, which, as a rule,, are partially filled with quartz, very minute cracks penetrate the inter- vening portions. Thus the pisolites appear to have lost a portion of their substance, so that it no longer fills the space within the outer shell, but has shrunk and formed the radial cracks. No analyses have been made of the different portions of the pisolites or of the pisolites and matrix separately, and it is impossible to say whether any differences in chemical composition exist. It may be that some soluble constituent has been removed from the interior of the pisolites, but it is more probable that the shrinking observed is due wholly to desiccation. 88 THE NON-METALLIC MINERALS. " Scattered throughout the ground-mass are occasional fragments of pisolites, whose irregular outlines have been covered to varying depths by a deposit of the same material as forms the concentric shells, and thus have been restored to spherical or oval forms." The following tables will serve to show the wide range of com- position of bauxites from various sources: COMPOSITION OF BAUXITES FROM VARIOUS LOCALITIES. Si0 2 . TiO 2 . A1 2 3 . Fe 2 O 3 . H 5 M rtw ^Oo^ s 2 1 5 ' S I - s 1 f * S g 1 f 1 ? q r F : : & - : : : : i : n : : : Location. coMPosn O M (H to C*> ^atovo O\Oo O\WOo O O fe 3 *J (X) o\ jH >vrM o\4^ O oow ^IOOK>- W J? O 1 c A _ ON /I \ -a v 2 v D J M H M M M H O U) * V t/t~ t C/l < H-a ^vS-tcSa^-U^ S oq p g 3 c ? b /i fc 8 3, a a AOitn^4^4b4hCM ^t M MvocntaJuvONO4>. M MCX^VOOI MOl 00-^1 ^.K3O\'OOO'-awO4^ f 5 & M CM co 01 t/i un . pv t>. . 2? < MM KJ o ; ; > ^ hH ( 3 K) I ! (0 OJ -fx M 1 00 . Oo Ca K> M . -vj KJ 1 Q s - o ^ oo K> c> ^ - H M K3 K) KJ vj Co O 4*. ON H vb b b ca bo b O *> O vO Ca HI H : ON 5 * ituents. o > 2 a '. '. '. ', Cn to ;::::: o ON p 1 % I > O f ? iil H 1 ! f! P . : I > jd ' ' ? ^ * O Miscellan< Ci < < o 3 i 5 v \ i I S N> B ^ V* r \< s . : : : -^ - :*::::: ^ ^ SvONO OO OOO O^O 3vQvO OO OOO 000 1 1 1 > - 1 ^ o- D 0, L i ( ^OACobbob-^rHHKJK) 3\OMOHO^woO O\ ON 112 THE NON-METALLIC MINERALS. Chromite, like magnetic iron, is black in color and of a metallic luster, but differs in being less readily if at all attracted by the magnet. On a piece of ground glass or white unglazed porcelain it leaves a brown mark, and fused with borax before the blowpipe it gives a green bead. Occurrence. Chromite is a common constituent in the form of disseminated granules of basic eruptive rocks belonging to the peri- dotite and pyroxenite groups and in the serpentinous and talcose rocks which result from their alteration. It is never found in true- veins or beds, though sometimes in segregated, nodular masses some- what simulating veins on casual inspection. Masses of pure mate- rial of more than a few pounds' weight are not common, though the national collections contain a block of fairly pure material from Lancaster County, Pennsylvania, of nearly 1,000 pounds' weight, and Whitney, in his report on the geology of California, makes mention of a mass at Mt. Diable 7 feet long, 5 J feet wide, and over 4 feet in. height. The more common form, as noted above, is that of small masses and detached granules, which, when freed from the inclosing rock, form the ore known as chrome sand. Deposits of chromite are now being worked near Black Lake Station, on the Quebec Central Railway, in close proximity to the asbestos mines. The ore here occurs in a series of pockets extending in an east-and-west direction. Some of the pockets are found lying in a dike of fine-grained granulite, but the possible relationship between the two has not been made out: While other deposits occur not associated with the granulite, it is to be noticed that the largest pockets of high-grade ore are thus associated. From one such pocket on the Lambly property over 500 tons of ore were taken,, yielding 54 per cent to 56 per cent sesquioxide of chromium. Aside from the localities above mentioned, chromic iron is found in pocket masses in the Cambrian and serpentinous rocks lying between the Vermont line and the Gaspe peninsula, but has never been successfully mined owing to the great uncertainty attending its occurrence. Chrome ore is also found in Newfoundland; the Russian Urals; in Asia Minor and European Turkey, and in Macedonia; in Aus- OXIDES. 113 tralia and New Zealand. In all cases so far as known the deposits occurring in peridotite or serpentine. The principal domestic sources of chromite are at present Del Norte, San Luis Obispo, Shasta, and Placer counties in California, though formerly mines in Lancaster County, Pennsylvania, and at the Bare Hills, near Baltimore, Maryland, were very productive. It is stated l by J. H. Fratt that in North Carolina chromite occurs under conditions very similar tc those of corundum, i.e., at and near the line of contact between the peridotite and gneissic rocks, being itself a product of crystallization from solution in the molten magma. Its distribution in this state is therefore essentially that of the peridotite. The ores thus far found are of a high grade, but the work thus far done has failed to bring to light a sufficient quantity to warrant extensive mining. Uses. Chromium is used in the production of the pigments chrome- yellow, orange, and green, and in the manufacture of bichro- mate of potash for calico printing and certain forms of electric bat- teries. A small amount is also used in the production of what is known as chrome steel. According to P. Speier, chrome-ore linings for reverberatory furnaces have been successfully adopted in French, German, and Russian steel works. The bottom and walls of the furnace are lined with chrome ore in large blocks, united by a cement formed by two parts of chrome ore finely ground, and one part of lime as free from silica as possible. " The introduction of chromium from the lining into the bath of molten steel only takes place to a very limited extent. From 660 to 1,100 pounds of limestone are charged into the furnace, and, according to the percentage of sulphur, from 220 to 440 pounds of manganese ore, for a charge of 1.5 to 1.7 ton of pig iron and 1,100 to 1,300 pounds of cast-iron scrap. About one- third, including steel scrap, is introduced into the furnace; and to this quantity is afterwards added from 660 to 1,100 pounds of wrought-iron scrap as soon as the melting is complete. When a suitable temperature is uotained the slag is run off, and the next charge is introduced 1 Trans. Am. Inst. Min. Engs., Vol. XXIX, 1899, p. 17. H4 THE NON-METALLIC MINERALS. into the furnace when the bath is quiescent. A sample is then taken and tested by bending, and if it be found that the percentage of phosphorus is too high, more lime, or lime and iron scale, are added, as much being introduced as the bath will take, and the addition of ferro-manganese is also made. " The iron chromate is decomposed only under the influence ex- erted by the reagents and oxidizing alkaline substances. Heat alone is insufficient to decompose chromate of iron, which may float in a bath of molten steel, covered with basic slag without dissolving. One of the principal conditions of success in the employment of the chrome-ore lining consists in carefully picking the pieces of ore used, which should be of uniform composition; and the best composition of ore used for lining reverberatory furnaces is found to be from 36 to 40 per cent of chromic oxide, 18 to 22 per cent of clay, 9 to 10 per cent of magnesia, and at most 5 per cent of silica." 1 Chromite has been also successfully used as a hearth-lining for copper- smelting purposes. 2 The following notes relative to the chrome industry in America are of sufficient interest to warrant reprinting here : 3 "The chrome industry is one of the most unique and character- istic in Baltimore. It originated in the early discovery of chrome ore in the serpentine of Maryland, and has ever since maintained its prestige as one of the sources of- the world's supply of the chromates of potassium and sodium, which have many applications in the arts. The following is the substance of an historical account of the Maryland chrome industry, kindly prepared by Mr. William Glenn: "In 1827 chrome ore was first discovered in America on land belonging to Mr. Isaac Tyson, in what are known as the Bare Hills, 6 miles north of Baltimore. Mr. Tyson's son, Isaac Tyson, Jr., then in business with his father, was persuaded by an English work- man to attempt the manufacture of 'chrome-yellow' from this material, and this was done in a factory on what is now Columbia 1 Journal of the Iron and Steel Institute, 1895, pp. 506, 507. Abstract from L'Echo des Mines, XXI, p. 584. 2 W. Glenn. Trans. Am. Inst. Min. Engs., Vol. XXXI, 1901, p. 374. 3 From Maryland, Its Resources, Industries, and Institutions, Baltimore, 1892, pp. 120-122. OXIDES. n5 Avenue, in Baltimore, in 1828. In the year of the discovery of the Bare Hill ore, Mr. Isaac Tyson, Jr., who seems to have possessed a very keen power of observation, as well as a considerable knowledge of chemistry, recognized in a dull, black stone which he saw sup- porting a cider barrel in Belair market, more of the same valuable material. Inquiry disclosed the fact that this had been brought from near Jarrettsville, in Harford County, where much more like it was to be found. Mr. Tyson at once examined the locality, and finding it covered with boulders worth $100 a ton in Liverpool, purchased a. considerable area. " Finding that the chrome ore was always confined to serpentine, Mr. Tyson began a systematic examination of the serpentine areas of Maryland, which could be easily traced by the barren character of the soil which they produce. A narrow belt of serpentine extends across Montgomery County, and while chrome ore is occasionally found in it (as, for instance, at Etchison post-office), nothing of economic importance has ever been discovered in Maryland south of the areas known as 'Soldiers' Delight' and 'Bare Hills.' North- eastward, however, the deposits become much richer. The region near Jarrettsville was productive, and thence the serpentine was traced to "the State line in Cecil County. Near Rock Springs the serpentine turns and follows the State line eastward for 15 miles. On the Wood farm, half a mile north of the State line and 5 miles north of Rising Sun, in Cecil County, Mr. Tyson discovered in 1833 a chromite deposit, which proved to be the richest ever found in America. This property was at once purchased by Mr. Tyson and the mine opened. At the surface it was 30 feet long and 6 feet wide, and the ore so pure that each 10 cubic feet produced a ton of chrome ore averaging 54 per cent of chrome oxide. The ore was hauled 12 miles by wagon to Port Deposit, and shipped thence by water to Baltimore and Liverpool. At a depth of 20 feet the vein narrowed somewhat, but immediately broadened out again to a length of 120 feet and a width of from 10 to 30 feet. The Wood Mine was worked almost continuously from 1828 to 1881, except between the years 1868 and 1873. During that time it produced over 100,000 tons of ore and reached a depth of 600 feet. It is not yet exhausted, but the policy of its owners is to reserve their ores 1 1 6 THE NON-METALLIC MINERALS. while they can be elsewhere purchased at a cheap rate. Another well-known chrome mine in this region is exactly on the State boun- dary at Rock Springs, and is called the Line pit. So much of this deposit as lay within the limits of Maryland was owned by Mr. Tyson, while he worked the Pennsylvania portion on a royalty." Other chrome openings near the Line pit were known as the "Jenkins Mine/' "Low Mine," "Wet pit,"' and "Brown Mine." This region has proved one of the best in the country for fine speci- mens of rare minerals. As a mineral locality it is usually given as "Texas, Pennsylvania." * During his exploration of the serpentine belt Mr. Tyson also noticed deposits of chromite sand, and to control the entire supply of this ore he either bought or leased these also, and worked them to some extent with his mines. "Between 1828 and 1850 Baltimore supplied most of the chrome ore consumed by the world; the remainder came from the serpen- tine deposits and platinum washings of the Urals. The ore was at first shipped to England, the principal consumers being J. and J. White, of Glasgow, whose descendants are still the chief manufac- turers of chromic- acid salts. In 1844 Mr. Tyson established the Baltimore Chrome Works, which are still successfully operated by his sons. " After 1850 the foreign demand for Baltimore ore declined gradu- ally till 1860, since which time almost none has been shipped abroad. The reason for this was the discovery in 1848 of great deposits of chromite near Brusa, 57 miles southwest of Constantinople, by Prof. J. Lawrence Smith, who was employed by the Turkish Govern- ment to examine the mineral resources of that country. Other deposits were also discovered by him 15 miles farther south, and near Antioch. These regions now supply the world's demand. "After the discovery of the magnitude of Wood pit, and of the bountiful supply of sand chrome to be found within the Baltimore region, Isaac Tyson, Jr., began to fear that the sources of supply could not much longer be restricted to his ownership. In such an 1 P. Frazer, Second Geological Survey of Pennsylvania, CCC, Lancaster County, j88o, pp. 176, 192. OXIDES. H7 event he realized that he would be compelled to manufacture his ores or to sacrifice them in competition. "The method of manufacture previously in use was to heat a mixture of chrome ore and potassium nitrate upon the working hearth of a reverberatory furnace. The potash salt yielded oxygen to the chromic oxide present, forming chromic acid, which, in turn, united with the base, producing potash chromate. The process was wasteful and exceedingly costly. Afterwards the process was some- what cheapened by substitution of potassium carbonate for the more costly nitrate; oxygen was taken from heated air in the furnace. But not until 1845, when Stromeyer introduced his process, was the manufacture of chromic acid placed upon a safe mercantile T^asis. In this process pulverized chromic iron is mixed with potas- sium carbonate and freshly slaked lime, and the mixture is heated in a reverberatory furnace. After chromic oxide is set free in the charge it is freely oxidized because of the spongy conditions of the lime -laden charge. " Among the first steps of Isaac Tyson, Jr., was to apply, in 1846, to Yale College for a chemist for his chrome works. In response a young man named W. P. Blake, who was then a student in the chemical laboratory, was sent. For a while Mr. Blake did excellent service in the new factory, but he was not willing to remain. " Mr. (now Professor) Blake was the first chemist to be employed in technology upon this continent, while the Baltimore works were the first to appreciate the value of chemistry. After the departure of Mr. Blake another chemist was secured from the first laboratory ever instituted for the teaching of chemistry, that founded at Giessen by Liebig. In succession came another chemist from the same laboratory, and this gentleman is yet employed in the works." Between 1880 and 1892 the annual production of chromite in the United States varied between 1,500 and 3,000 tons. During the succeeding decade the production was greatly diminished, statistics for 1901 showing an output, wholly from California, of but 498 tons, valued at about $15.00 per ton. Some 20,000 tons were imported during this same year. The principal sources of supply are now Canada, Greece, New Caledonia, New South Wales, and Turkey. THE NON-METALLIC MINERALS. BIBLIOGRAPHY. Lake Chrome and Mineral Company, of Baltimore County. American Mineral Gazette and Geological Magazine, I, April i, 1864, P- 253- HARRIE WOOD. Chromite and Manganese. Mineral Products of New South Wales, Department of Mines, 1887, p. 42. Ueber schwedisches Chromroheisen und Martinchromstahl. Berg-und Huttenmannische Zeitung, XL VII, 1888, p. 267. Die Chromersenerz-Lagerstatten Neuseeland. Berg-und Huttenmannische Zeitung, XL VII, 1888, p. 375. Chrome Iron. Eighth Annual Report of the State Mineralogist of California, 1888, p. 326. Chromite Mined at Cedar Mountain. Eighth Annual Report of the State Mineralogist of California, 1888, p. 32. Chrome Iron Ore from Orsova. Journal of the Iron and Steel Institute, 1889, p. 316. Chrome Iron, Shasta County. Tenth Annual Report of the State Mineralogist of California, 1890, p. 638. Chromium in San Luis Obispo County. Tenth Annual Report of the State Mineralogist of California, 1890, p. 582. Chrome Iron in New Zealand. Engineering and Mining Journal, LIV, 1892, p. 393. Chromic Iron. Twelfth Report of the State Mineralogist of Califorina, 1894, p. 35. J. T. DONALD. Chromic Iron in Quebec, Canada. Engineering and Mining Journal, LVIII, 1894, p. 224. Chromic Iron: Its Properties, Mode of Occurrence and Uses. Journal of the General Mining Association of the Province of Quebec, 1894-95, p. 108. W. F. WILKINSON. Chrome Iron Ore Mining in Asia Minor. Engineering and Mining Journal, LX, 1895, p. 4. WM. GLENN. Chrome in the Southern Appalachian Region. Transactions of the American Institute of Mining Engineers, XXV, 1895, p 481. Chromic Iron. Thirteenth Report of the State Mineralogist of California, 1896, p. 48. GEORGE W- MAYNARD. The Chromite Deposits on Port au Port Bay, New Found- land. Transactions of the American Institute of Mining Engineers, XXVII, 1897, p. 283 J. H. PRATT Chromite in North Carolina. Engineering and Mining Journal, LXVII. 1899, p. 261. The Occurrence, Origin, and Chemical Composition of Chromite, with especial reference to the North Carolina Deposits. Transactions of the American Institute of Mining Engineers, XXIX, 1899, p. 17. OXIDES. 119 10. MANGANESE OXIDES. The element manganese exists in nature under many different forms, of which those in combination as oxides, carbonates, and silicates alone need concern us in this work. The principaF known oxides are Manganosite (MnO); Hausmannite (MnO,Mn 2 O 3 ); Braunite(3Mn 2 O 3 ,MnSiO 3 ); Polianite (MnO 2 ) ; Pyrolusite (MnO 2 ); Manganite (Mn 2 O 3 ,H 2 O); Psilomelane (H 4 MnO 5 ); and Wad, the last being, perhaps, an earthy impure form of psil'omelane. To this list should be added the mineral franklinite, a manganiferous oxide of iron and zinc. Of these, the first named, manganosite, is rare, having thus far been reported only in small quantities associated with other oxides in Wermland, Sweden. The other forms are described somewhat in detail as below. It should be stated, how- ever, that with the exception of the well-crystallized forms it is often difficult to discriminate between them, as they occur admixed in all proportions, and, moreover, one variety, as pyrolusite, may result from the alteration of another (manganite). The better defined species may be separated from one another by their comparative hardness, streak, and hydrous or anhydrous properties, as shown in the accompanying table. Variety. Hardness. Specific Gravity. Color. Streak. Anhydrous or Hydrous. Franklinite. . . . 5.5 to 6 . 5 5 to 5 . 2 2 Iron-black Reddish brown to black Anhydrous. Hausmannite . . 5 5-5 4-7 4-85 Brown-black Chestnut-brown Do. Braunite 6 6.5 4-7 4-85 Brown-black to steel- gray Brown-black Do. Polianite 6 6.5 4.8 4.9 Light steel-gray. . . . Black Do. Pyrolusite 2 2.5 4.8 Iron-black to steel- gray or bluish. . , . Blacker blue-black. , a Do. Manganite 4 4.2 4.4 Dark steel-gray to iron-black Red-brown to black. . Hydrous. Psilomelane. . . S-6 3.7 4-7 Iron-black to steel- gray Brown- black Do. a. Usually yields water in closed tube. The chemical relationship of the ores as found in nature is thus set forth by Penrose: 1 1 Annual Report of the Geological Survey of Arkansas, I, 1890, p. 541. 120 THE NON-METALLIC MINERALS. Chemical Composition. Anhydrous Form. Hydrous Form. Protoxide (MnO) . . Manganbsite (MnO) .... Hausmannite (M^OJ . .. Braunite (Mn O ) Pyrochroite (MnO.H^O). Mancranite (Mn 2 O 3 ,H 2 O). j Psilomelane. ( Wad. Proto-sesquioxide (Mn 3 O 4 ) . Peroxide (MnO ) Pyrolusite, Pobanite (MnO 2 ) Manganese oxides frequently occur admixed in indefinite pro- portions with the hydrous oxide of iron, limonite, giving rise to the manganiferous limonites. Franklinite. This may be termed rather as a manganiferous ore of iron and zinc than a true ore of manganese. Nevertheless, as the residue after the extraction of the zinc is used in the manu- facture of spiegeleisen, we may briefly refer to it here. The mineral occurs in rounded granules or octahedral crystals of a metallic luster and iron-black color, associated with zinc oxides and silicates in crystalline limestones, at Franklin Furnace, New Jersey. It bears a general resemblance to the jnineral magnetite, but is less readily attracted by the magnet and gives a strong manganese reaction. Its average content of manganese oxides Mn 2 O 3 and MnO is but from 15 to 20 per cent. Hausmannite. This form of the ore when crystallized usually takes the form of the octahedron, and. may be readily mistaken for franklinite, from which, however, it differs in its inferior hardness, lower specific gravity, and in being unacted upon by the magnet. It occurs in porphyry, associated with other manganese ores, in Thuringia; is also found in the Harz Mountains; Wermland, Sweden, and various other European localities. In the United States it is reported as occurring only in Iron County, Missouri. The mineral in its ideal purity consists of sesquioxide and protoxide of manganese in the proportion of 69 parts of the former to 31 of the latter. Analyses of the commercial article as mined are not at hand. Braunite. This, like hausmannite, crystallizes in the form of the octahedron, but is a trifle harder. Chemically it differs, in that analyses show almost invariably from 7 to 10 per cent of silica, though as to whether or no this is to be considered an essential constituent it is as yet difficult to say. Analyses I and II, on p. 256, OXIDES. 121 show the composition of the mineral as found. The ore is reported as occurring both crystallized and massive in veins traversing por- phyry at Oehrenstock in Ilmenau, in Thuringia, near Ilefeld in the Harz; Schneeberg, Saxony, and various other European localities. Also at Vizianagram in India; in New South Wales, Australia, and in the Batesville region, Arkansas. Polianite. Like pyrolusite, yet to be noted, this form of the ore is chemically a pure manganese binoxide, carrying some 63.1 per cent metallic manganese combined with 36.9 per cent oxygen. From pyrolusite it is readily distinguished by its increased hardness. So far as reported, it is a rather rare form of manganese, though possibly much that has been set down as pyrolusite may be in reality polianite. Pyrolusite occurs in the form of iron-black to steel-gray, some- times bluish opaque masses, granular, or commonly in divergent columnar aggregates sufficiently soft to soil the fingers, and in this respect easily separated from the other common forms excepting wad. Not known in crystals except as pseudomorphs after manganite. Its composition is quite variable, usually containing traces of iron, silica, and lime, and sometimes barium and the alkalies. Analyses III and IV, on p. 122. as given by Penrose, will serve to show the general average. This is a common ore of manganese, and is extensively mined in Thuringia, Moravia, Bohemia, Westphalia, Transylvania, Australia, Japan, India, New Brunswick, Nova Scotia, and various parts of the United States. Manganite differs and is readily distinguishable from the other ores thus far described, in carrying from 3 to 10 per cent of com- bined water, which can readily be detected when the powdered mineral is heated in a closed tube. From either psilomelane or pyrolusite it is distinguished by its hardness. When in crystals it takes prismatic forms with the prism faces deeply striated longi- tudinally. Its occurrence is essentially the same as that of braunite. Psilomelane. This is, with the possible exception of pyrolusite, the commonest of the manganese minerals. The usual form of occurrence is that of irregular nodular or botryoidal masses em- bedded in residual clays. It is readily distinguished from manganite 122 THE NON-METALLIC MINERALS. or wad by its hardness, and from hausmannite. braunite, or polianite by yielding an abundance of water when heated in a closed tube. The sample from the Crimora Mines in Virginia, shown in Plate IX, is characteristic. The composition of the commercial ore is given in analyses V, VI, and VII, below. Wad or Bog Manganese is a soft and highly hydrated form of the ore, as a rule of little value, owing to impurities (analysis VIII). Asbolite is the name given to a variety of wad containing cobalt (see p. 28). See further Rhodonite and Rhodochrosite, pp. 159, 204. ANALYSES OF MANGANESE ORES. Constituents. Braunite. Pyrolusite. Psilomelane. Wad. I. II. III. IV V VI VII VIII MnO . 87.47 9.62 86.95 9-85 90.15 88.98 8499 1048 8027 14.10 63-46 25.42 o Fe O 2-55 O-2I CaO 3 " ' OS 1 4 35 K X 2.84 BaO 0.48 0.18 2.25 1. 12 2.80 2.05 SiO, 980 6 oo HO -95 3352 "7^ I. Batesville region Arkansas. II. Elgersburg Germany. III. Cheverie. Nova Scotia. IV. Cape Bjreton. "V Batesville region Arkansas. VI Schneeberg Saxony VII Cnmora Virginia VIII. Big Harbor Cape Breton. Origin. The deposits of manganese oxides which are of sufficient extent to be of commercial importance are believed to be in all cases of secondary origin; that is, to have resulted from the decompo- sition of preexisting manganiferous silicate constituents of the older crystalline rocks and the subsequent deposition of the oxides in secondary strata. Indeed in many instances the ore has undergone a natural segregation, owing to the decomposition of the parent rock and the accumulate of the manganese oxide, together with other difficult soluble constituents in the residual clay. Thus Penrose has shown 1 that the deposits of the Batesville (Arkansas) region result from the decay of the St Clair limestone, the various stages of which are illustrated in the accompanying Plate X. The fresh 1 Annual Report of the Geological Survey of Arkansas, I, 1890. IDEAL SECTIONS SHOWING THE FORMATION OF MANGANESE-BEARING CLAY FROM THE DECAY OF THE ST.CLAIR LIMESTONE. ssUeooNE CHERT E3 MANGANESE-BEARING CLAY CHJIZARO LIMESTONE S3 ST.CLAIR LIMESTONE: EEjSACCHARoiDAi. FIG.I. ORIGINAL, CONDITION or THE ROCKS. , i r i i i FIQ.2. FIRST STAGE OF DECOMPOSITION. FIG. 3. SECOND STAGE OF DECOMPOSITION. FIG. 4. THIRD STA8E OF DECOMPOSITION. PLATE X. OXIDES. 123 limestone, as shown by analysis, contains but 4.30 per cent manga- nese oxide (MnO), while the residual clay left through its decom- position contains 14.98 per cent of the same constituent. Occurrence. As above noted, the ore is found in secondary rocks, &nd as a rule in greatest quantities in the clays and residual deposits resulting from their breaking down. The usual form of the ore is that of lenticular masses or nodules distributed along the bedding planes, or heterogeneously throughout the clay. Penrose describes the Bates ville ores as sometimes evenly distributed throughout a large body of clay, but in most places as being in pockets surrounded by clay itself barren of ore. These pockets vary greatly in character, being sometimes comparatively solid bodies separated by thin films of clay, and containing from 50 to 500 tons of ore; sometimes they consist of large and small masses of ore embedded together, and again at other times of small grains, disseminated throughout the clay. In the Crimora (Virginia) deposits the ore (psilomelane) is found in nodular masses in a clay resulting from the decomposition of a shale which has been preserved from erosion through sharp synclinal folds. The position and association of these deposits may be best understood by reference to the accompanying figures, 1 Fig. 17 being that of the ground plan of the immediate vicinity of the mine, while Fig. 1 8 represents cross sections along the lines marked in Fig. 17. The country rock is a massive Potsdam sandstone overlaid by shales, the latter having undergone extensive decomposition, giving rise to clay deposits in which the ore now occurs. At the east, along the line A A in Fig. 17, the sandstone dips to the westward. At CC is an anticline from which the beds dip both toward the west and east, forming thus a syncline the axis of which is indicated by the line BB. The sections across -this syncline (Fig. 18) show the accumulated clay from the decomposition of the shales, in which the man- ganese occurs. The ore is found very irregularly distributed throughout the clay in lumps and masses from the size of a small pebble to those weighing a ton or more. The basin is described 1 From Geological Notes on the Manganese Ore Deposit of Crimora, Virginia. By Charles E. Hall, Trans. Am. Inst. of Min. Engs., Vol. XX, 1891, pp. 47, 48. 124 THE NON-METALLIC MINERALS. FIG. 17. Ground plan manganese deposits, Crimora, Va. [After C. E. Hall.] SECTION No. 2 SECTION No. 4 FIG. 1 8. Sections through Crimora manganese deposits. [After C. E. Hall.] OXIDES. 125 as some 500 feet in width and 800 to 900 feet in length, the ore-bearing clay extending to a maximum depth, so far as determined, of 300 feet. The manganese appears to have been here originally disseminated throughout the sandstone and shales and to have leached out, pre- sumably as a carbonate, by percolating water, and redeposited in the basin, where the flow was retarded for a sufficient time for oxida- tion to take place. In Cuba, manganese is found, so far as known, only in the prov- ince of Santiago, the principal occurrence being in a belt lying back of the Sierra Maestra and extending from the vicinity of Guantanamo upon the east to Manzanillo upon the west. The ore, which may be either manganite, pyrolusite, or wad, singly or all together, occurs as a rule upon hills or knolls composed of sedimentary rocks sand- stones and limestones in disconnected or pocket deposits and under such conditions as to point unmistakably to an origin through the influence of circulating waters. The ore is often associated with a hard jasper, or "bayate," occurring in large masses, or in the form of disseminated nodules or veinlets in the ore. The occurrence and association are such as to indicate that the two substances were deposited nearly contemporaneously, and from the water of hot springs. Branner has described the manganese (psilomelane) deposit of Bahia, Brazil, as occurring in the form of a sheet or bed of from a few decimeters to ten meters thickness, standing at an angle of 60 in decomposed mica schist. Bog manganese is described as occurring in an extensive deposit near Dawson settlement, Albert County, New Brunswick, on a branch of Weldon Creek, covering an area of about 25 acres. In the center it was found to be 26 feet deep, thinning out toward the margin of the bed. The ore is a loose, amorphous mass, which could be readily shoveled without the aid of a pick, and contained more or less iron pyrites disseminated in streaks and layers, though large portions of the deposit have merely a trace. The bed lies in a valley at the northern base of a hill, and its accumulation at this particular locality appears* to be due to springs. These springs are ftill trickling down the hillside, and doubtless the process of pro- 126 THE NON-METALLIC MINERALS. during bog manganese is still going on. 1 A bed of manganese ore in the government of Kutais, in the Caucasus, is described as occur- ring in nearly horizontally lying Miocene sandstones. The ore is pyrolusite and the bed stated as being 6 to 7 feet in thickness. Mining and preparation. The mining and preparation of man- ganese ores is, as a rule, a comparatively simple process. At the Crimora (Virginia) mines the material is excavated by means of shafts and tunnels, and taken to the surface, where it is crushed, washed, screened, and dried for shipment. The machinery all works automatically, and the ore is not handled after having once passed into the crusher. 2 Uses. According to Professor Penrose, 3 the various uses to which manganese and its compounds are put may be divided into three classes: Alloys, oxidizers, and coloring materials. Each of these classes includes the application of manganese in sundry manufac- tured products, or as a reagent in carrying on different metallurgical and chemical processes. The most important of these sources of consumption may be summarized as follows : Alloys Oxidizers Spiegeleisen . Ferromanganese Manganese bronze Silver bronze - Alloys of manganese and iron. Alloys of manganese and copper, with or without iron. An alloy of manganese, aluminum, zinc, and copper, with a certain quantity of silicon. Alloys of manganese with aluminum, zinc tin lead, mag- nesium, etc. Manufacture of chlorine. Manufacture of bromine. As a decolorizer of glass (also for coloring glass, see coloring materials). As a dryer in varnishes and paints. LeClanche's battery. Preparation of oxygen on a small scale. Manufacture of disinfectants (manganates and permanganates). ( Calico printing and dyeing. Coloring materials.. Colorin g 8 lass ' P^tery, and brick. j Paints. Green. Violet. 1 Annual Report of the Geological Survey of Canada, VII, 1894, p. 146 M. 2 The washing plant and a vertical section of the works of the Crimora Mines are given in the Engineering and Mining Journal for March 22, 1890, the same having drawn for its information on the American Manufacturer of Pittsburg. (Date not given.) 3 Annual Report of the Geological Survey of Arkansas, I, 1890. OXIDES. 127 Besides these main uses a certain amount is utilized as a flux in smelting silver ores, and, in the form of its various salts, is employed in chemical manufacture and for medicinal purposes. Pyrolusite and some forms of psilomelane are utilized in the manufacture of chlorine, and for bleaching, deodorizing, and disinfecting purposes; also in the manufacture of bromine. In glass manufacture the manganese is used to accomplish two different results: First, to remove the green color caused by the presence of iron, and second, to impart violet, amber, and black colors. The amount of manganese actually used for other than strictly metallurgical purposes in the United States is, however, small. 1 The value depends somewhat upon the uses to which it is to be applied. Pyrolusite and psilomelane only are of value in the production of chlorine as above noted. These are rated, as stated by Penrose, according to their percentages of peroxide of manganese (MnO 2 ). The standard for the German ores is given at 57 per cent MnO^, and 70 per cent for Spanish. For the manufacture of spiegeleisen the prices are based on ores containing not more than 8 per cent silica and o.io per cent phosphorus, and are subject to deductions as follows: For each i per cent silica in excess of 8 per cent, 15 cents a ton; for each 0.02 per cent phosphorus in excess of o.io per cent, i cent per unit of manganese. Settlements are based on analysis made on samples dried at 212, the percentage of moisture in samples as taken being deducted from the weight. The prices paid at Bessemer, Pennsylvania, in 1894, based on these percentages, were as below: Manganese. Prices per Unit. Iron. Manganese Ore containing above 49 per cent Ore containing 46 to 40 per cent Cents 6 6 6 6 Cents 28 27 26 2 5 Ore containing 43 to 46 per cent. . . Ore containing 40 to 43 per cent 1 Mineral Resources of the United States, 1892. p 178 128 THE NON-METALLIC MINERALS Otherwise expressed, the value ranges from $5 to $12 a ton, according to quality and condition of the market. It is probable that the total consumption in pottery and glass manufacture does not exceed 500 tons a year, of which about two- thirds are used in glass making. The amount used in bromine manu- facture and the other purposes enumerated probably amounts to another 500 tons. The remainder is used in connection with iron and steel manufacture, chiefly in the production of steel and a pig iron containing considerable manganese for use in cast-iron car wheels. In the crucible process of steel manufacture manganese is charged into the pots, either as an ore at the time of charging the pots, or it is added as spiegeleisen or ferromanganese at the time of charging or during the melting, usually toward the close of the melting, so as to prevent too great a loss of manganese by oxidation. In the Bessemer and open-hearth process the manganese is added as spiegel- eisen or ferromanganese at or near the close of the process, just before the casting of the metal into ingots. It has been found in recent years that a chilled cast-iron car wheel containing a percentage of manganese is much toughen stronger, and wears better than when manganese is absent. For this reason large amounts of manganiferous iron ores are used in the manufacture of Lake Superior pig iron intended for casting into chilled cast-iron car wheels. (See also The Mineral Industry, VIII 1899.) II MINERAL WATERS. From a strictly scientific standpoint any water is a mineral water, since water is itself a mineral an oxide of hydrogen. Common usage has, however, tended toward the restriction of the name to such waters as carry in solution an appreciable quantity of other mineral matter although the actual amounts may be extremely variable. Of the various salts hel'd in solution, those of sodium, calcium, and iron are the more common, and more rarely, or at least in smaller amounts, occur those of potassium, lithium, magnesium, strontium, silicon, etc. The most common of the acids is carbonic, and the next probably sulphuric. OXIDES. 129 Classification. The classification of mineral water is a matter attended with great difficulty from whatever standpoint it- is ap- proached. Such classification may be either geographic, geologic, therapeutic, or chemical, though the first two are naturally of little value, and the therapeutic, with our present knowledge, is a prac- tical impossibility. The chemical classification is, on the whole, preferable, although even this, owing to the great variation of methods of stating results used by analytical chemists, is at present attended with some difficulty. Dr. A. C. Peale, the well-known authority on American mineral waters, has suggested the scheme given below, 1 and from his writings has been gleaned a majority of the facts here given. According to their temperatures as they flow from the springs the waters are divided primarily into (A) thermal and (B) non-thermal, a thermal water being one the mean annual temperature of which is 70 F. or above. Each of these groups is again subdivided according to the character of the acids and their salts held in solution as below : Class I. Alkaline. Class II. Alkaline-saline. Saline f Sulphated. /-i -nr A -j ] Muriated. Classiv - Acid ......... Any spring of water may be characterized by the presence or absence of gas when it is designated by one of the following terms: (i) Non-gaseous (free from gas). (2) Carbonated (containing car- bonic-acid gas). (3) Sulphureted (containing hydrogen sulphide). (4) Azotized (containing nitrogen gas). (5) Carbureted (having carbureted hydrogen). In cases where there is a combination of gases such is indicated by a combination of terms, as sulphocarbonated, etc. The classes may be further subdivided according to the predominating salt in solution, as (i) sodic, (2) lithic, (3) potassic, (4) calcic, (5) magnesic, (6) chalybeate, (7) aluminous. 1 Annual Report of the United States Geological Survey, 1892-93, p. 64. 130 THE NON-METALLIC MINERALS. The alkaline waters, Class I above, include those which are characterized by the presence of alkaline carbonates. Generally such are characterized also by the presence of free carbonic acid. Nearly one-half the alkaline springs of the United States are calcic-alkaline, that is, carry calcium carbonate as the principal constituent. The saline waters include those in which sulphates or chlorides predomi- nate. They are more numerous than are the alkaline waters. The alkali-saline class includes all waters in which there is a combination of alkaline carbonates with sulphates and chlorides; the acid class includes all those containing free acid, which is mainly carbonic, though it may be sicilic, muriatic, or sulphuric. The character of the salts held in solution is the same for both thermal and non- thermal springs, though as a general rule the amount of salt is greatest in those which are classed as thermal. Thus at the Hot Springs of Virginia one of the springs, with a temperature of 78 F., has 18.09 grains to the gallon of solid contents, while another, with a temperature of 110 F., has 33.36 grains to the gallon. Source of mineral waters. Pure water is a universal solvent and its natural solvent power is increased through the carbonic acid which it takes up in its passage through the atmosphere, and by this same acid and other organic and inorganic acids and the alkalies which it acquires in passing through the soil and rocks. The water of all springs is meteoric, that is, it is water which has fallen upon the earth from clouds, and gradually percolating downward issues again in the form of springs at lower levels. In this passage through the superficial portion of the earth's crust it dissolves the various salts, the kind and quantity being dependent upon the kind of rocks, the temperatures and pressure of the water, as well as the amount of absorbed gases it contains. Both the mineral contents and the temperature of spring waters are dependent upon the geological features of the country they occupy. As a rule springs in regions of sedimentary rocks carry a larger proportion of salts than those in regions of eruptive and meta- morphic rocks. Thermal springs are, as a rule, limited to regions of comparative recent volcanic activity, or where the rocks have been disturbed, crushed, folded, and faulted, as in mountainous regions. OXIDES. PRODUCTION OF MINERAL WATERS IN 1899 BY STATES AND TERRITORIES. State or Territory. Springs Report- ing. Product. Value. Alabama 4 38 II 12 2 2 6 18 12 3 6 4 26 ii 39 21 4 6 12 6 7 46 7 15 2 25 4 5 2 6 15 3 6 39 3 7 30 4 Gallons. 38,900 48,602 1,464,075 642,850 338,017 168,500 17,000 128,040 858,95 162,475 40, 200 36,i75 63,5 1,850,132 100,380 4,439,041 3,045,400 2,078,700 271,500 551.876 469,800 332,000 46,800 4,454,057 103,150 2,494,473 45.500 1,542,800 195,000 3 22 564 138,645 346,700 4,729.950 7.850 53.917 954,689 54,000 32,220 4,089,329 263,782 $19,917 17,442 698,493 172,970 50,685 10,275 7.250 24,770 101,090 25.255 3.320 2,718- 7.032 179.450 13.045 230,704 368,235 54,704 48,292 262,705 190,990 171,380 7.77 809,056 20,715 w^s 9,700 340,254 15,000 33.45 44,073 55,658 155,047 i,95S 15,869 341,769 7,002 18,305 701,367 75. 8 47 California Colorado Connecticut District of Columbia . ... Florida . . Georgia .... Illinois Indiana Iowa Kansas Kentucky Ivlaine . .... A'laryland ... .... Massachusetts Michigan . . Minnesota Mississippi Ivtissouri New Hampshire . . New Jersey . . . New M^exico . New York North Carolina Ohio Oregon Pennsylvania Rhode Island South Carolina South Dakota ... , . Tennessee ... Texas Utah Vermont \Vashington West Virginia . \Visconsin . . Other States a Total 479 62 37,021,539 2,540,597 5,484,694 1,463,336 Estimated production of springs not reporting sales. . Grand total 54i 39,562,136 6,948,030 a. The States in which only one spring for each has made are port are included here. States are Idaho, Louisiana, Montana, and Nebraska. These 132 THE NON-METALLIC MINERALS. Occasional thermal springs are met with in undisturbed areas, but such are regarded as of deep-seated origin, and to owe their tempera- tures to the great depths from which they are derived. Distribution. Mineral springs of some sort are to be found in each and all of the States of the American Union, though naturally the resources of the more sparsely settled States have not as yet been fully developed. For this reason the table given on page 131 is to a certain extent misleading. Uses. The mineral waters are utilized mainly for drinking and bathing purposes, the thermal springs being naturally best suited for bathing, and the non-thermal for drinking purposes. .V. CARBONATES. I. CALCIUM CARBONATE. Calcite, Calc Spar, Iceland Spar. These are the names given to the variety of calcium carbonate crystallizing in the rhombohedral division of the hexagonal system. The mineral occurs under a great variety of crystalline forms, which are often extremely perplexing to any but an expert mineralogist. The chief distinguishing charac- teristics of the mineral are (i) its pronounced cleavage, whereby it splits up into rhombohedral forms, with smooth, lustrous faces, and (2) its doubly refracting property, which is such that when looked through in the direction of either cleavage surfaces it gives a double image. It is to this property, accompanied with its trans- parency, that the mineral, as a crystallized compound, owes its chief value, though as a constituent of the rock limestone it is applied to a great variety of industrial purposes. When not sufficiently transparent for observing its doubly refracting properties the mineral is readily distinguished by its hardness (3 of Dana's scale) and its easy solubility, with brisk effervescence, in cold dilute acid. This last is likewise a characteristic of aragonite, from which it can be distinguished by its lower specific gravity (2.65 to 2.75) and its cleavage. Calcium carbonate, owing to its ready solubility in terrestrial waters, is one of the most common and widely disseminated Basalt Fig. 2. Fig. 3. XThfCaveD PLATE XL Views showing Occurrence of Calcite in Iceland. [U. S. National Museum.] CARBONATES. 133 of compounds. Only the form known as double spar, or Iceland spar, need here be considered. Origin and mode of occurrence. Calc spar is invariably a second- ary mineral occurring as a deposit from solution in cracks, pockets, and crevices in rocks of all kinds and all ages. The variety used for optical purposes differs from the rhombohedral cleavage masses found in innumerable localities only in its transparency and freedom from flaws and impurities. The chief commercial source of the mineral has for many years been Iceland, whence has arisen the term Iceland spar, so often applied. For the account of the occur- rences of the mineral at this locality, as given below, we are indebted mainly to Th. Thoroddsen. 1 The quarry is described as situated on an evenly sloping mountainside at Reydarfjorden, about 100 meters above the level of the ocean and a little east of the Helgus- tadir farm. (See Plate XI.) The veins of spar are in basalt, and at this spot have been laid bare through the erosive action of a small stream called the " Silfur- lakur," the Icelandic name of the spar being " Silfurberg " The quarry opening is on the western side of this brook, and at date of writing was some 72 feet long by 36 feet wide (see Fig. i of plate). In the bottom and sides of this opening the calc spar is to be seen in the form of numerous interlocking veins, ramifying through the basalt in every direction and of very irregular length and width, the veins pinching out or opening up very abruptly. In Fig. 2 of plate is shown an area of some 40 square feet of the basaltic wall rock, illus- trating this feature of the occurrence. Fig. 3 of the same plate shows the largest and most conspicuous vein, the smaller having been omitted in the sketch. The high cliffs on the north side of the quarry are poorer in calc-spar veins, the largest dipping underneath at an angle of about 40. A comparatively small proportion of the calc spar as found is fit for optical purposes. That on the immediate surface is, as a rule, lacking in transparency. Many of the masses, owing presumably to the development of incipient fractures along cleavage lines, show internal, iridescent, rainbow hues; such are known locally as ^eologiska Foreningens I, Stockholm Forhandlingar, XII, 1890, pp. 247-254. 134 THE NON-METALLIC MINERALS. " litsteinar" (lightstones). Others are penetrated by fine, tube-like cavities, either empty or filled with clay, and still others contain cavities, sometimes sufficiently large to be visible to the unaided eye, filled with water and a moving bubble. The most desirable material occurs in comparatively small masses embedded in a red-gray clay, filling the vein-like interspaces in the bottom of the pit. The non- transparent variety, always greatly in excess, occurs in cleavable masses and imperfectly developed rhombohedral, sometimes i to 2 feet in diameter, associated with stilbite. Calc spar has been exported in small quantities from Iceland since the middle of the seventeenth century, though the business was not conducted with any degree of regularity before the middle of the present century, prior to that time every one taking what he liked or could obtain, asking no one's permission. About the time Bartholin discovered the valuable optical properties of the mineral (in 1669), the royal parliament under Frederick III granted the necessary permission for its extraction. 1 It was not, however, until 1850 that systematic work was begun, when a merchant by the name of T. F. Thomsen, at Seydisf jord, obtained permission of the owner of some three- fourths of the property (the pastor Th. Erlends- son) to work the same. The quarried material was then transported on horseback to the Northfjord, and thence to Seydisfjord by water. In 1854 the factor H. H. Svendsen, from Eskifjord, leased the pastor's three-fourths' right for 10 rigsdalers a year, and the remaining fourth, belonging to the Government, for 5 rigsdalers. Svendsen worked the mine successfully up to 1862, when one Tullinius, at Eskifjord, pur- chased the pastor's three-fourths and leased the Government's share for five years, paying therefor the sum of 100 rigsdalers (about $14 or $15). This lease was renewed for four years longer at the rate of 5 rigsdalers per year, and for the year 1872 at the rate of 100 rigsdalers, when the entire property passed into the hands of the Government in consideration of the payment of 16,000 kroner (about $3,800). From that time until 1882 the mine remained idle, when operations were once more renewed, though not on an extensive scale, owing, presumably in part, to the fact that Tullinius, the 1 Laws of Iceland, I, 1668, pp. 321, 322. , CARBONATES. 135 last year he rented the mine, had taken out a sufficient quantity to meet all the needs of the market. Over 300 tons of the ordinary type of the spar is stated to have been sent to England and sold to " factory " owners (Fabrikanter) at about 30 kroner a ton, though to what use it was put is not stated. Aside from the locality at Helgustadir, calc spar in quantity and quality for optical purposes is known to occur only at Djupi- fjordur, in West Iceland. The Reydharfjordhr locality was also visited by Mr. J. L. Hoskyns-Abrahall in the summer and autumn of 1889, whose account * is reproduced in part below. Sudhrmula Sysla, of which Reydharfjordhr, the largest, bisects the east coast of Iceland, are cut out of an immense plateau, formed of horizontal sheets of volcanic rock, chiefly trachyte, between 3,000 and 4,000 feet high. This has been subsequently eroded into sharp, bare ridges with immense cliffs or steep slopes falling from them, parted by torrent valleys and fjords, the greater part of the district not reaching the present snow line. It is on one of these slopes, which slants down at an angle of forty degrees into Reydharfjordhr, that the unique quarry of, Iceland spar is found. It consists of a cavity in the rock about 12 by 5 yards and some 10 feet high, originally filled almost entirely, but now only lined, with immense crystals, which are fitted so closely together as to form a compact mass, like a lump of sugar, with grains averaging 10 inches across. The Syslumadhur, 2 Jon Asmundarson Johnsen, had given me leave to examine the cave and take as many specimens as I liked, but the permission was not of very much use, there being about 5 feet of water nearly all over the bottom; and such specimens as I did get involved doing severe penance in walking barefoot over sharp crystals. The floor is covered with a thin layer of very fine chocolate-brown mud, which sticks as tenaciously to one's feet as to the crystals. I had to resort to tooth powder to get the latter clean, though the great heaps of spar which lie on the pathside and in front of the mouth of the cave were all washed by the rain till they 1 Mineralogical Magazine, IX, 1890, p. 179. 2 Magistrate, public notary, receiver of taxes, liquidator, auctioneer, etc. 136 THE NON-METALLIC MINERALS. were as bright and transparent as ice. The water now running through the cave is incapable of forming calc spar. It appears, like the surrounding rocks, to contain an excess of silicic acid, and either etches the surface of the spar wherever it comes in contact with it, or covers it with stilbite, the characteristic zeolite of the doleritic and basaltic rocks in Iceland. The rock in which the cave is formed is a dolerite, and darker in color than the surrounding phonolite, which is traversed by veins of black and green pitchstone. In the neighborhood of the spar it is disintegrated, colored slightly with green earth, and full of microscopic crystals of stilbite and calcite. The quarry was worked till 1872 by Herra Tullinius, a Danish merchant of Eskifjord. The trading station is an hour and a half's ride from Helgastadir, the nearest farm to the quarry. (In Iceland all distances are measured in terms of the hour's ride, tima, and the day's journey, leidh.) The Icelandic Government in that year bought a quarter share of the quarry, and stopped the work, so that Tullinius was glad to sell them the rest. Five years ago an attempt was made to reopen it. One man was employed, and after spending about a week in the cave he succeeded in pumping out the water and extracting a fine block of clear spar, which was sold at a high price in London. Here, however, the work dropped, and in consequence Tullinius remains the proprietor of the whole of the calc spar that is available for physical work, and naturally sells it at a price that is calculated to make his very moderate stock last for a considerable time. 1 The reason of the Icelandic Government is not very clear, but as the working of the quarry is, perhaps from patriotic motives, delegated to Herr Gunnarsson, an Icelandic merchant, whose nearest warehouse is at Seydhisfjord, a good day's ride from Eski- fjord, it is hardly to be expected that the buried treasure will soon see the light. Perhaps, too, the specimens of the best quality have been already removed. Certainly clear pieces do not constitute the great mass of the spar, and if M. Labonne, who visited the cave in May, 1877 (the water being at that time frozen), could extract it " en assez grande abondance " 2 he did not leave much exposed for l lt is sold by Thor E. Tullinius, Slotsholmsgade 16, Copenhagen K. 2 Comptes Rendus, CV, 1887, p. 1144. CARBONATES. 137 me to take two years later. M. Labonne speaks in his note of ramifications into the environing rock which have never been worked and suggests that this investigation might in'crease the importance of the quarry. Such ramifications as I could see were on a very small scale. On the other hand, the thickness of the deposit has not yet been ascertained, but it is said that the best pieces occurred near the surface. For the most part the calcite is rendered semi- opaque by innumerable cracks, generally following the gliding and cleavage planes ( JR and R), and apparently produced by the pressure of the spar itself, but sometimes following the conchoidal fracture. Remarkable examples of the latter kind are in the British Museum. Chalk. This is the name given to a white, somewhat loosely coherent variety of limestone composed of the finely comminuted shells of marine mollusks, among which microscopic forms known as foraminifera are abundant. The older text-books gave one to understand that foraminiferal remains constituted the main mass of the rock, but the researches of Sorby 1 showed that fully one- half the material was finely comminuted shallow- water forms, such as inoceramus, pecten, ostrea, sponge spicules, and echinoderms. Chalk belongs to the Cretaceous era, occurring in beds of varying thickness, alternating with shales, sands, and clays, and often in- cluding numerous nodules of a dark chalcedonic silica to which the name flint is given. Though a common rock in many parts of Europe, it is known to American readers mainly by its occurrence in the form of high cliffs along the English coast, as near Dover. Until within a few years little true chalk was known to exist within the limits of the United States. According to Mr. R. T. Hill 2 there are, however, extensive beds, sometimes 500 feet in thickness, extending throughout the entire length of Texas, from the Red River to the Rio Grande, and northward into New Mexico, Kansas, and Arkansas. These chalks in many instances so closely simulate the English product, both in physical properties and chemical composition, as to be adaptable to the same economic purposes. The following Address to Geological Society of London, February, 1879. 2 Annual Report of the Arkansas Geological Survey, II, 1888. 133 THE NON-METALLIC MINERALS. analyses from the report above alluded to serve to show the com- parative composition: Lower Upper White White Cretaceous Cretaceous ' Cliff Chalk of Gray Constituents. Chalk, Chalk, Chalk, Shore- Chalk, Burnet Rocky Little ham, Folkstone, County, Texas. Comfort, Arkansas. River, Arkansas. Sussex, England. England. Carbonate of lime ........... 92 42 8848 04.. l8 08 4.O O4. OO Carbonate of magnesia . . ..... i.t8 Trace. 1.37 08 7T Silica and insoluble silicates 9-77 3-49 I.IO Ferric oxide and alumina . . .... .41 I.2S 1. 4. 1 Phosphoric acid, alumina, and loss 4.2 Trace. Chloride of sodium I 20 Water .18 .70 99.98 99-5 IOI 100 100 Chalk is used as a fertilizer, either in its crude form or burnt, in the manufacture of whiting, in the form of hard lumps by carpenters and other mechanics, and in the manufacture of crayons. Washed, chalk is used to give body to wall paper; as a whitewash for ceilings; as a thin coating on wood designed for gilding, being for this purpose mixed with glue; to vary the shades of gray in water-color paints, and as a polishing powder for metals. Concerning the importation and uses of chalk it is stated : * " Paris white is the name given to the white coloring substance prepared by grinding cliffstone, a variety of chalk or limestone which is as hard as some building stones and has a greater specific gravity than the ordinary chalk. It is imported from Hull, England, and sells at from $2 to $4 per ton ex vessel, according to freight rates from Hull. During the calendar year 1884, 3,905^ tons of cliffstone were imported at New York. "The paris white made in this country is sold at from $1.10 to $1.25 per hundredweight, in casks, according to make and quality. The paris white made in England, of which 508,185 pounds were imported at New York during the calendar year 1884, sells at from $1.25 to $1.30 per hundredweight. There is apparently no differ- ence in quality between the cliffstone ground in this country and the 1 Mineral Resources of the United States, 1883-84, p. 930. CARBONATES. 139 imported paris white. Its principal use is in the preparation of kal- somine. It is also employed in the manufacture of rubber, oLcloth, wall papers, and fancy glazed papers. . . . " Until recently all of the whiting used in this country was ground from chalk imported from Hull, England. The annual production of whiting is about 300,000 barrels. The price varies, according to the quality, from 35 to 90 cents per hundredweight. There are four grades made, as follows: Common whiting, worth from 35 to 40 cents; gilders' whiting, 60 to 65 cents; extra gilders' whiting, 70 to 75 cents; American paris white, 80 to 85 cents. The uses of whiting are about the same as paris white, which it closely resembles. The crude chalk, it should be stated, is brought mainly as ballast from England and France. Limestones, Mortars, and Cements. Pure limestone, or calcium carbonate, is a compound of calcium oxide and carbonic acid in the proportion of 56 parts of lime (CaO) to 44 parts of the acid (CO 2 ). In its crystalline form, as exemplified in some of our white marbles, the rock is therefore but an aggregate of imperfectly outlined calcite crystals, or, otherwise expressed, is a crystalline granular aggregate of calcite. In this form the rock is white or colorless, sufficiently soft to be cut with a knife, and dissolves with brisk effervescence when treated with dilute hydrochloric or nitric acid. Sulphuric acid will not dissolve it except in small proportions, since the exteriors of the granules become converted shortly into insoluble calcium sulphate (gypsum), which protects them from further attack. As a constituent of the earth's crust, however, absolutely pure limestone is practically unknown, all being contaminated with more or less foreign material, either in the form of chemically combined or mechanically admixed impurities. Of the chemically combined impurities the most common is magnesia (MgO), which replaces the lime (CaO) in all proportions up to 21.7 per cent, when the rock becomes a dolomite. This in its pure state can readily be distin- guished from limestone by its greater hardness and in its not effer- vescing when treated with cold dilute acid. (See p. 151.) It dis- solves with effervescence in hot acids, as does limestone. As above noted, all stages of replacement exist, the name magnesian or 140 THE NON-METALLIC MINERALS. dolomitic limestone being applied to those in which the magnesia exists in smaller proportions than that above given (21.7 per cent). Iron in the form of protoxide (FeO) may also replace a part of the :^me. Of the mechan ca ly admixed impurities silica in the form of quartz sand or various more or less decomposed silicate minerals, clayey and carbonaceous matter, together with iron oxides, are the more abundant. These exist in all proportions, giving rise to what are known as siliceous, aluminous, or clayey, carbonaceous, and ferruginous limestones. Phosphatic material may exist in vary- ing proportions, forming gradations from phosphatic limestones to true phosphates. Limestones are sedimentary rocks formed mainly through the deposition of calcareous sediments on sea bottoms; many beds, however, as the oolitic limestones, show unmistakable evidences of true chemical precipitation. They are in all cases eminently strati- fied rocks, though the evidences of stratification ' may not be evident in the small specimen exhibited in museum collections. Varietal names other than those mentioned above are given, and which are dependent upon structural features or other peculiarities. A shaly limestone is one partaking of the nature of shale. Chalk is a fine pulverulent limestone composed of shells in a finely com- minuted condition and very many minute foraminifera, as already noted. The name chalky limestone is frequently given to an earthy limestone resembling chalk. Marl is an impure earthy form, often containing many shells, hence called shell marl. An oolitic lime- stone is one made up of small rounded pellets like the roe of a fish. The name marble is given to any calcareous or even serpentinous rock possessing sufficient beauty to be utilized for ornamental purposes. Uses. Aside from their uses as building materials, lithographic purposes, etc., as described elsewhere, limestones are utilized for a considerable variety of purposes, the most important being that of the manufacture of mortars and cements. Their adaptability to this purpose is due to the fact that when heated to a temperature of 1,000 F. they gradually lose the carbonic acid, becoming converted into anhydrous calcium oxide (CaO), or quicklime, as it is popularly called; and further, that this quicklime when brought in contact CARBONATES. 141 with water and atmospheric air greedily combines with, first, the water, forming hydrous calcium oxide (CaOH 2 O), and on drying once more with the carbonic acid of the air, forming a more or less hydrated calcium carbonate. In the process of combining with water the burnt lime (CaO) gives off a large amount of heat, swells to nearly twice its former bulk, and falls away to a loose, white powder. This when mixed with siliceous sand forms the common mortar of the bricklayers, or, if with sand and hair, the plaster for the inferior walls of houses Quicklime formed from fairly pure calcium carbonate sets or hardens after but a few days' exposure, the induration it is stated, being due in part to crystallization. The less pure forms of limestone, notably those which contain upwards of lo- per cent of aluminous silicates (clayey matter), furnish, when burned, a quicklime which slakes much more slowly so slowly, in fact, that it is not infrequently necessary to crush to powder after burning. The same quicklimes when slaked are further differen- tiated from those already described by their property of setting (as the process of induration is called) under water. Hence they are known as hydraulic limes, and the rocks from which they are made as hydraulic limestones. Their property of induration out of con- tact with the air is assumed to be due to the formation of calcium and aluminum silicates. Inasmuch as these silicates are practically insoluble in water, it follows that quite aside from their greater strength and tenacity they are also more durable ; indeed there seems no practical limit to the endurance of a good hydraulic cement, its hardness increasing almost constantly with its antiquity. Certain stones contain the desired admixtures of lime and clayey matter in just the right proportion for making hydraulic cement. In the majority of cases, however, it has been found that a higher grade, stronger and more enduring material, can be made by mixing in definite proportions, determined by experiment, the necessary con- stituents obtained, it may be, from widely separated localities. The exact relationship existing between composition and adaptability to lime-making does not seem as yet to be fully worked out. As is well known, the pure while crystalline varieties yield a quicklime inferior to the softer blue-gray, less metamorphosed varieties. Neverthe- less, there are certain distinctive qualities, due to the presence and 142 THE NON-METALLIC MINERALS. character of impurities, which led Gen. Q. A. Gillmore to adopt the following classification : (1) The common or fat limes, containing, as a rule, less than 10 per cent of impurities. (2) The poor or meagre limes, containing free silica (sand) and other impurities in amounts varying between 10 per cent and 25 per cent. (3) The hydraulic limes, which contain from 30 to 35 per cent of various impurities. (4) The hydraulic cements, which may contain as much as 60 per cent of impurities of various kinds. As above noted, most cements are manufactured from a variety of materials, and their consideration belongs therefore more properly to technology. Nevertheless it has been thought worth the while here to give in brief the matter below relative to a few of the more important and well-known varieties now manufactured. Portland Cement. This takes its name from a resemblance of the hardened material to the well-known oolitic limestone of the island of Portland in the English Channel. As originally made on the banks of the Thames and Medway, it consists of admixtures of chalk and clay dredged from the river bottoms, in the proportions of three volumes of the former to one of the latter, though these proportions may vary according to the purity of the chalk. These materials are mixed with water, compressed into cakes, dried and calcined, after which it is ground to a fine powder and is ready for use. The following analyses from Heath's Manual of Lime and Cement will serve to show the varying composition of the chalk and clay from the English deposits: Constituents. Upper chalk. Gray chalk. Clay. Calcium carbonate .............. 97.90 to 98.60 .66 1.59 .IO .21 35 -74 87.35 1.6 7 .IO .38 I.I4 .42 to 96.52 6.84 5 .46 93 4.29 | 55 to 3 ii 3 4 i 4 70 15 24 4 8 2 5 Silica .............. Alumina Potash and soda Lime . - IvTagnesia .... ... CARBONATES. It is stated that the presence of more than very small quantities of sand, iron oxides, or vegetable matter in the clay is detrimental. A good cement mud before burning may contain from 68 to 78 per cent of calcium carbonate, 21 to 15 per cent of silica, and from 10 to 7 per cent of alumina. The following analyses from the same source as the above serve to show (I) the composition of the clay; (II) the mixed clay and chalk or " slurry," as it is called, and (III) the cement powder pre- pared from the same: Constituents. I. Ctay. II. Slurry. III. Cement. Lime . .... 62 1 3. Calcium sulphate 212 Calcium, carbonate 2 OI 60 07 Silica (soluble) CA 14. 11.77 20.4.^ Alumina . .............. 14. 68 4..4.C '"to 8.05 A A& i"-Jo 2 8? "/ 1.48 7.76 2.11 4.37 Sand .87 1.24 *T'Oi .08 Water I ^ O3 7 I w or THE (( UNIVERSITY CARBONATES. 147 Overton, Tennessee Canada (light -blue gray) . . Canada (dark -blue gray) . . Solenhofen, Bavaria . . Kentucky (light gray) Iowa (blue-gray) Missouri (ligfit gray) Missouri, Rails County . . . Solenhofen, Bavaria .... Solenhofen, Bavaria (dark) Solenhofen, Bavaria (yellow p Si rfr- n' 00 00 - bo on 00 sv tO M H H O M 1 OO O\ H ^ O Oo to to Oo M ON I O to Oo p p O On to to j,. ff Oo Oo to -P OA M Oo ->-l on O vo O H 10 bo b vO O Oo Insoluble Silica. M M 00 O &3 Cf* > ^Oo O O O O Oo to 10' If O O : : : O O M 4- H t i O H ff , Oo H M o o o w g- * Oo to vO 4^- 4*. Oo Oo 4*> , v O vO $ to to to to to to to ff > Oi to O bo o 2-2. p O P ^ [ Authority. 148 THE NON-METALLIC MINERALS. France, and also Silesia, India, and the British American possessions. By far the best stone, and indeed the only stone which has as yet been found to satisfactorily fill all the requirements of the lithog- rapher's art, and which is the one in general use to-day wherever the art is practiced, is found at Solenhofen, near Pappenheim, on the Danube, in Bavaria. These beds are of Upper Jurassic or Kimmer- Idgian Age and form a mass some 80 feet in thickness, though natu- rally not all portions are equally good or adapted for the same kind of work. The stone varies both in texture and color in different parts of the quarry, but the prevailing tints are yellowish or drab. In the United States materials partaking of the nature of lithographic stone have been reported from Yavapai County, Arizona; Talla- dega County, Alabama ; Arkansas ; Lawrence County, Indiana ; near Thebes and Anna, Illinois; James and Van Buren counties, Iowa; Hardin, Estelle, Kenton, Clinton, Meade, Rowan, Wayne, and Simpson counties, Kentucky ; near Saverton, Rails County, Missouri ; Clay and Overton counties, Tennessee; Burnet and San Saba counties, Texas; near Salt Lake City, Utah, and at Fincastle, Vir- ginia. While, however, from nearly, if not quite every one of these localities, it was possible to get small pieces which served well for trial purposes, each and every one has failed as a constant source of supply of the commercial article, and this for reasons mainly in- herent in the stone itself. It is very possible that ignorance as to proper methods of quarrying may have been a cause of failure In. some cases. The Arizona stone is one of the recent discoveries, and according to first reports seems also most promising. Samples of the stone submitted to the writer, as well as samples of work done upon it, seemed all that could be desired. It is stated by Mr. W. F. Blandy that the quarries are situated on the east slope of the Verdi range, :about 2 miles south of Squaw Peak and at an elevation of about 1,200 feet above the Verdi Valley, 40 miles by wagon road east of Prescott. Two quarries have thus far been opened in the same strata, about 1,000 feet apart, the one showing two layers or beds 384 feet in thickness, and the other three beds 3,188 feet -in thick- ness. As at present exposed the beds, which are of Carboniferous Age, are broken by nearly vertical fissures into blocks rarely 4 or 5 feet CARBONATES. 149 in length. Owing to the massive form of the beds and the conchoidal fracture the stone can not be split into thin slabs, but must be sawn. No satisfactory road yet exists for its transportation in blocks of any size, and such material as has thus far been produced is in small slabs such as can be "packed." Those who have inspected the properties express themselves as satisfied that blocks of good size and satisfactory quality can be had in quantity. The Alabama stone as examined by the writer is finely granular and too friable for satisfactory work. Qualitative tests showed it to be a siliceous magnesian limestone. It is, of course, possible that the single sample shown does not fairly represent the product. The Arkansas deposit is situated in Township 14 N., R. 15 W. of the 5th p.m., sections 14, 23, and 24, Searcy County. The color is darker than that of the Bavarian stone. The reports of those who have tested it are represented as being uniformly favorable. The Illinois stone is darker, but to judge from the display made in the Illinois building at the World's Columbian Exposition, 1893, is capable of doing excellent work and can be had in slabs of good size. The Indiana stone is harder than the Bavarian, and samples examined were found not infrequently traversed by fine, hard veins of calcite. The stone from Saverton, Missouri, is compact and fine grained, with, however, fine streaks of calcite running through it. It leaves only a small brownish residue when dissolved in dilute acid. This stone has been worked quite successfully on a small scale. The State geologist, in writing on the subject, says : 1 " Some of the beds of the St. Louis limestone (Subcarboniferous) have been successfully used for lithographic work. No bed is, however, uniformly of the requisite quality, and the cost of selection of available material would seem to preclude the development of an industry for the production of lithographic stone." From the deposit at Overton, Tennessee, it is stated slabs 40 by 60 inches by 3 J inches thick were obtained, though little, if anything, is now being done. An analysis of this stone is given in the table. Other promising finds are reported from McMinn County, in the 1 Bulletin No. 3, Geological Survey of Missouri, 1890, p. 38. 150 THE NON-METALLIC MINERALS. same State. According to the State geological reports, the stone lies between two beds of variegated marble. The stratum is thought to run entirely through the county, but some of the stone is too hard for lithographic purposes. The best is found 8 miles east of Athens on the farm of Robert Cochrane, and a quarry has been opened by a Cincinnati company, which pays a royalty of $250 per annum. It is sold for nearly the same price as the Bavarian stone. It is a calcareous and argillaceous stone, formed of the finest sediment, of uniform texture, and possesses a pearl-gray tint. The best variety of this stone has a conchoidal fracture and is free from spots of all kinds. In Meade County, Kentucky, the stone furnishing the best lithographic material occurs * in a nearly horizontal layer about 3 feet in thickness. The entire output is stated to be "of good quality for an engraving and printing base for certain classes of work." The stone is of a blue-gray color, can be had in large sizes, and is being quite generally used in the south and southwest, where it is stated to compare very favorably with the imported Bavarian material. The quarries are operated by the American Lithographic Stone Company, located at Brandenburg. In Rowan County the stone, according to E. O. Ulrich, 2 occurs in nearly horizontal layers interstratified with yellow limestone, arenaceous oolite, and shales belonging to the St. Louis division of the Subcarboniferous formations. The quarries .now developed lie east and across the river from the town of Yale. The bed yielding lithographic material is some 15 feet in thick- ness, and is overlaid by an equal thickness of stripping. The presence of flattened nodules of flint form the chief drawback as the quarry is at present developed. The stone has been tested in the lithographic department of the U. S. Geological Survey and found satisfactory. A lithographic stone is described in the State survey reports of Texas as occurring at the base of the Carboniferous formations near Sulphur Springs, west of Lampasas, on the Colorado River, and to be traceable by its outcrops for a distance of several miles, the most 1 S. J. Kubel, Engineering and Mining Journal, November 23, 1901, p. 668. 2 Engineering and Mining Journal, June 28, 1902, p. 895. CARBONATES. 151 favorable showing being near San Saba. The texture of the stone is good, but as it is filled with fine reticulating veins of calcite, and as moreover the lithographic layer itself is only some 6 or 8 inches in thickness, it is obvious that little can be expected from this source. A stone claiming many points of excellence has for some years been known to exist in the Wasatch range within a few miles of Salt Lake City, and several companies are or have been engaged in its exploitation. Very encouraging reports of beds examined by men whose opin- ions should be conservative, come from Canadian sources, and it is possible a considerable industry may yet be here developed, though little is being done at present. The descriptions as given in the geological reports are as follows: 1 " The lithographic stones of the townships of Madoc and Mar- mora and of the counties of Peterboro and Bruce have been examined and practically tested by lithographers, and in several ca:es pro- nounced of good quality; they have also obtained medals at various exhibitions. They were obtained from the surface in small quarries, and possibly when the quarries are more developed better stones, free from 'specks' of quartz and calcite, will be available in large slabs." It should be stated that in actual use the principal demand is for stones some 22 or 28 by 40 inches; the largest ones practically used are some 40 by 60 inches and 3 to 3^ inches thick. The better grades sell as high as 22 cents a pound. 2. DOLOMITE. This is a carbonate of calcium and magnesium (Ca,Mg), CO 3 ,= calcium carbonate, 54.35 per cent; magnesium carbonate 45.65 per cent. Hardness 3.5 to 4; specific gravity, 2.8 to 2.9; colors when pure, white, but often red, green, brown, gray or black from impuri- ties. Dolomite, like calcite, occurs in massive beds or strata either compact or coarsely crystalline, and is to the eye alone often indis- tinguishable from that mineral. Like limestone, the dolomites occur x Geology of Canada, 1863. 152 THE NON-METALLIC MINERALS. in massive forms suitable for building purposes, or in some cases as marble. From the limestone they may be distinguished by their increased hardness and by being insoluble in cold dilute hydrochloric acids. The dolomites, like the limestones, are sedimentary rocks, though it is doubtful if the original sediments contained sufficient magnesium carbonate to constitute a true dolomite. They are regarded rather as having resulted from the alteration of limestone strata by the replacement of a part of the calcium carbonate by carbonate of magnesium. Uses. Aside from its use as a building material, dolomite has of late come into use as a source of magnesia for the manufacture of high ] y refractory materials for the linings of converters in the basic processes of steel manufacture. According to a writer in the Indus- trial World 1 the magnesia is obtained by mixing the calcined dolo- mite with chloride of magnesia, whereby there is formed a soluble calcic chloride which is readily removed by solution, leaving the insoluble magnesia behind. According to another process the cal- cined dolomite is treated with dissolved sugar, leading to the forma- tion of sugar of lime and deposition of the magnesia; the solution of sugar of lime is then exposed to carbonic acid gas, which separates the lime as carbonate, leaving the sugar as refuse. Recently it has been proposed to use magnesia as a substitute for plaster of Paris for casts, etc. The snow-white coarsely crystalline Archean dolomite com- mercially known as snowflake marble, and which occurs at Pleasant- ville, in Westchester County, New York, is finely ground and used as a source of carbonic acid in the manufacture of the so-called soda and other carbonated waters. 3. MAGNESITE. This is a carbonate of magnesium, MgCO 3 , = carbon dioxide, 52.4 per cent; magnesia, 47.6 per cent. Usually contaminated with carbonates of iron and free silica. The following analysis will serve to show the average run of the material, both in the crude state and after calcining: ^une i, 1893. CARBONATES, 153 Constituents. Styria. Greece. Crude magnesite. GO O tO O6.O od. d.6 0.5 tO 2.O 4 40 Carbonate of iron . . 3.0 to 6.0 FeO 0.08 I.O 0.52 0.5 Water 0.54 Burnt magnesite. 77.6 82.46 to 95.36 7.7 0.83 to 10.92 Alumina and ferric oxide J7 O o c 6 to T, . ^ 4. Silica 1.2 0.77 to 7.08 The mineral occurs rarely in the form of crystals, but is commonly in a compact, finely granular condition of white or yellowish color somewhat resembling unglazed porcelain, and more rarely crystal- line granular, like limestone or dolomite. It is hard (3.5 to 4.5) and brittle, with a vitreous luster, and is unacted upon by cold, but dissolves with brisk effervescence in hot hydrochloric acid. Localities and mode of occurrence. Most commonly the mineral is found in the form of irregular veins in serpentinous and other magnesian rocks, being a decomposition product either of the ser- pentine itself or of the original rock from which the serpentine is derived. It is also found in granular aggregates disseminated throughout serpentinous rocks. It is stated by Dana to occur associated with gypsum. Professor W. P. Blake has described 1 immense beds of very pure magnesite as occurring in the foothills of the Sierra Nevadas, between Four and Moorecreeks, in what is now Tulare County California. The beds are from i to 6 feet in thickness and are interstratified with talcose and chloritic schists and serpentine. Mr. H. G. Hanks, who has since inspected these deposits, reports them as existing in several hills or low mountains, the mineral cropping out boldly in distinct and clearly marked veins, varying from 2 inches to 4 feet, and of a maximum length, as exposed, of 500 feet. In section 5, 1 Pacific Railroad Reports, V, p. 308. 154 THE NON-METALLIC MINERALS. T. 15 S., R. 24 E., Fresno County, Californ'a, there is s'ated 1 to be a large vein of the material averaging 10 feet in width, incased in hornblendic and micaceous shales. A white marble-like crystalline granular variety has been found in the form of drift bowlders on an island in the St. Lawrence River near the Thousand Islands Park. According to Canadian geologists, magnesite forming rock masses occurs associated with the dolomites, serpentines, and streatites of the eastern townships of Quebec. In Bolton it occurs in an enor- mous bed resembling .crystalline limestone in appearance. An analysis of this yielded: Carbonate of magnesia, 59.13 per cent; carbonate of iron, 8.72 per cent; silica, 32.20 per cent. In the township of Sutton a slaty variety yielding as high as 80 per cent of carbonate of magnesium occurs admixed wMi feldspar and green chromiferous mica. In Styria the material lies in Silurian beds consisting of argillaceous shales, quartzites, dolomites, and lime- stones, resting upon gneiss. The extensive deposit of magnesite occurring associated with Subcarboniferous limestones in the Swiss Tyrol is regarded by M. Koch 2 as due to a decomposition of the original limestone through percolating magnesia-bearing solutions. Magnesia being the stronger base replaces the lime, which is carried away in solution. The chief localities of magnesite, native and foreign, are as follows: Maryland, Bare Hills, Baltimore County. New Jersey, Hoboken. Massachussets, Roxbury. New York, near Rye, West- chester County; Warwick, Orange County; Stony Point, Rockland County; New Rochelle, Westchester County; Serpentine Hills, Staten Island. North Carolina, Webster, Jackson County; Hamp- tons, Yancey County, McMakins Mine, Cabarrus County. Penn- sylvania, Goat Hill, West Nottingham, Cheste: County; Scott's Mine, Chester County; Low's Chrome Mine, Lancaster County. Califorina, Coyote Creek, near Madison Station, Southern Pacific Railroad, Santa Clara County; Gold Run, Iowa Hill, and Damascus' Placer County; Arroyo Sero, Monterey County; Mariposa and Tuolumne counties; Diablo Range, Alameda County; between 1 Tenth Annual Report of the State Mineralogist of California, 1890, p. 185. 2 Zeitschrift der Deutschen Geologischen Gesellschaft, XLV, Pt. 2, 1893, p. 294. CAR60NATES. 155 Four Creek and Moore's Creek, near Visalia, Tulare County; Alameda County; Napa County; Millcreek, Fresno County. Wash- ington, Spokane County. Sutton, Quebec, lot 12, range 7; Bolton, Quebec. Regla, near Havana, Cuba. Konigsberg, Norway. Pied- mont, Italy. Bingera Diamond Fields, New South Wales. Victoria, South Australia. Kosewitz and Frankenstein, Silesia. Styria, in Austria-Hungary. Greece. Uses. Magnesite is used in the preparation of magnesian salts (Epsom salts, magnesia, etc.), in the manufacture of paint, paper, and fire-brick. For the last-named purpose it is said to answer admirably, particularly where a highly refractive material is needed, as in the so-called basic process of iron smelting. " Magnesia made from the carbonate (magnesite) by driving off the carbonic acid is very refractory if pure. It is made into any shape that is required, and is one of the most refractory of substances. It was formerly very difficult to get the carbonate of magnesia, but large quantities of it have been found on the island of Eubcea, so that it can now be had for $15 to $25 per ton, instead of $60 to $70 as formerly. It can be calcined at a less cost than ordinary lime, losing half of its weight, so that if calcined before it is transported the cost may be still further reduced. It contains a little lime, silicates of iron, and some serpentine and silica. After calcination, the serpentine and silica can be separated, as it is easily crushed, but the most of the work can be done by hand-picking beforehand. Before moulding it must be submitted to about the temperature it is to undergo in the furnace, otherwise it would contract. It is then mixed with a certain portion of less-calcined material, which is one- sixth for steel fusion, and 10 to 15 per cent water by weight, and pressed in iron moulds. If for any reason either because there was too much or too little water, or because the material was not properly mixed, or contains silica the crucible is not strong enough, it has only to be dipped in water which has been saturated with boracic acid and then heated." 1 Twenty or more years ago the mineral was mined from serpen- 1 T. Egleston, Transactions of the American Institute of Mining Engineers, IV, 1876, p. 261. 156 THE NON-METALLIC MINERALS. tinous rocks in Lancaster County, Pennsylvania, by McKim, Sines & Co. ; of Baltimore, by whom it was used for the manufacture of Epsom salts (sulphate of magnesia) Although it is said 1 that these gentlemen made a pure salt at less price than it could be imported, and thereby excluded the foreign material almost exclusively, the mines are now wholly abandoned* Isaac Tyson & Co., of the same city, also operated mines in Lan- caster County. " Early in the fall of 1886 a small force of men was set to work on the deposits of magnesite discovered on Cedar Mountain, Alameda County, California. Since that time several carloads of the mineral have been gotten out and shipped by rail to New York, these de- posits being only a few miles from the line of the Central Pacific Railroad. The mineral occurs here in a decomposed serpentine rock and in a yellow clay in which are embedded large bowlders* It lies in pockets and small veins, the latter running in every direction* The richest spots are found 'under the bowlders, where the mineral is quite pure. A machine is used to sift out the small stones from the powdered magnesite, a good deal of which is met with. A number of veins of this mineral has been exposed by the occurrence of land- slides on the side of the mountain where they are situated; only a few of them, however, contain good mineral, nor is there any cer- tainty as to how long these will last. The claims are being opened by tunnels, of which two have been started. The process of gather- ing this mineral is slow, as every piece has to be cleaned by hand, and the whole has to be carefully assorted according to purity. Having been divided into three classes, it is put up in sacks weighing from 80 to 100 pounds each This sacking is preliminary not only to shipping but to getting it down from the mountains, which can be done only on the backs of animals While carbonate of magnesia occurs at a great many places in California and elsewhere on the Pacific coast, the above is the only deposit of this mineral that is being worked. An artificial article of this kind is obtained as a by- product in the manufacture of salt by the Union Pacific Salt Com- pany of California." 2 1 Report C. C. C. Second Geological Survey of Pennsylvania, p. 178. 8 Mineral Resources of the United States, 1886, p. 696. CARBONATES. 157 Th. Schlossing has proposed 1 to utilize magnesian hydrate obtained by precipitation from sea water by lime for the preparation of fire-brick, the hydrate being first dehydrated by calcination at a white heat, after which it is made up into brick form. According to the Industrial World 2 magnesite as a substitute for barite in the manufacture of paint is likely to prove of impor tance. The color, weight, and opacity of the powder add to its value for this purpose. In Europe it is stated the material is used as an adulterant for the cheaper grades of soap. Prices. During 1892 the material, 96 to 98 per cent pure, was quoted as worth $9 to $15 a ton in New York City. Material containing as high as 15 to 30 per cent silica and 8 to 10 per cent of iron is said to be practically worthless. Crude magnesite is quoted as worth from $3 to $4 a ton at the mines. 4. WITHERITE. This is a carbonate of barium of the formula BaCo 3 ,= baryta, 77.7 per cent, carbon dioxide, 22.3 per cent. Color, white to yellow or gray, streak white; translucent. Hardness, 3 to 3.75; specific gravity, 4.29 to 4.35. When crystallized, usually in form of hexagonal prisms, with faces rough and longitudinally striated. Common in globular and botryoidal forms, amorphous, columnar, or granular in structure. The powdered mineral dissolves readily in hydrochloric acid, like calcite, but is easily distinguished from this mineral by its great weight and increased hardness, as well as by its vitreous luster and lack of rhomboidal cleavage, which is so pronounced a feature in calcite. From barite, the sulphate of barium, with which it might become confused on account of its high specific gravity, it is readily distinguished by its solubility in acids as above noted. From strontianite it can be distinguished by the green color it imparts to the blow-pipe flame. Localities and mode oj occurrence. The mineral occurs appar- ently altogether as a secondary product filling veins and clefts in older rocks and often forming a portion of the gangue material of metal- 1 Comptes Rendus. 1885; p. 137. 'Industrial World, XXXVI, No. 20, 1891. *5 THE NON-METALLIC MINERALS. liferous deposits. The principal localities as given by Dana are Alston Moor, Cumberland, where it is associated with galena; in large quantities at Fallowfield, near Hexam in Northumberland; at Anglezarke in Lancashire; at Arkendale in Yorkshire, and near St. Asaph in Flintshire, England; Tarnowitz, Silesia; Szlana, Hungary; Leogang in Salzburg; the mine of Arqueros near Co- quimbo, Chile; L. Etang Island; near Lexington, Kentucky, and in a silver-bearing vein near Rabbit Mountain, Thunder Bay, Lake Super'or. Uses.-* The mineral has been used to but a slight extent in the arts. As a substitute for lime it has met with a limited application n making plate glass, and is also said to have been used in the manu- facture of beet-sugar, but is now being superseded by magnesite. 5. STRONTIANITE. This is a carbonate of strontium, SrCO 3 , = carbon dioxide, 29.9 per cent; strontia, 70.1 per cent. Often impure through the presence of carbonates and sulphates of barium and calcium. Colors, white to gray, pale green, and yellowish. Hardness, 3.5 to 4. Specific gravity 3.6 to 3.7. Transparent to translucent. When crystallized often in acute, spear-shaped forms. Also in graunlar, fibrous, and columnar globular forms. Soluble like calcite in hydrochloric acid, with effervescence, but readily distinguished by its cleavage and greater density. The powdered mineral when moistened with hydro- chloric acid and held on a platinum wire in the flame of a lamp imparts to the flame a very characteristic red color. Occurrence. According to Dana the mineral occurs at Strontian in Argyllshire, in veins traversing gneiss, along with galena and barite; in Yorkshire, England; at the Giant's Causeway, Ireland; Clausthal in the Harz; Braunsdorf, Saxony; Leogang in Salzburg; near Brixlegg, Tyrol; near Hamm and Munster, Westphalia. In the United States, at Schoharie, New York, in the form of granular and columnar masses and also in crystals, forming nests and geodes in the hydraulic limestone; at Clinton, Oneida County; Chaumont Bay and Theresa, Jefferson County; and Mifflin County, Pennsyl- vania. CARBONATES. 159 Uses. Strontianite, so far as the writer has information, has but a limited application in the arts. It is stated 1 that " basic bricks " are prepared from it by mixing the raw or burnt Strontianite with clay or argillaceous ironstone in such proportions that the brick shall contain about 10 per cent of silica, and then working it into a plastic mass with tar or some heavy hydrocarbon. After molding, the bricks are dusted with fine clay or ironstone, dried, and burned. The effect of the dusting is to form a glaze on the surface, which protects the brick from the moisture of the air. Like celestite, it is also used in the production of the red fire of fireworks. The demand for the material is small, and the price but from $2.50 to $4 a ton. 6. RHODOCHROSITE ; DIALOGITE. This is a pure manganese carbonate of the formula MnCO 3 ,= carbon dioxide, 38.3 per cent; manganese protoxide, 61.7 per cent. The color is much like that of rhodonite (see p. 204), from which, however, it is readily distinguishable by its rhombohedral form, inferior hardness (3.5 to 4.5), and property of dissolving with effer- vescence in hot hydrochloric acid, while rhodonite is scarcely at all attacked. The mineral is a common constituent of the gangue of gold and silver ores, as at Butte, Montana; Austin, Nevada, etc. So far as known the mineral has as yet no commercial value. 7. NATRON, THE NITRUM OF THE ANCIENTS. This is a hydrous sodium carbonate, Na 2 CO 3 + ioH 2 O, = carbon dioxide, 15.4 per cent; soda, 21.7 per cent; water, 62.9 per cent. Occurs in nature, according to Dana, only in solution, as in the soda lakes of Egypt and elsewhere, or mixed with other sodium car- bonates. The artificially crystallized material is of white color when pure, soft, and brittle, and with an alkaline taste. Crystals, thin, tabular, monoclinic. Thermonatrite, also a hydrous sodium carbonate of the formula Na 2 CO 3 +H 2 O, = carbon dioxide, 35.5 per cent; soda, 50 per cent, and water 14.5 per cent, occurs under similar conditions, and is considered as derived from natron as a 1 Journal of the Society of Chemical Industry, III, 1884, p. 33. 160 THE NON-METALLIC MINERALS. product of efflorescence. (See further under Sodium sulphates, P- 3330 8. TRONA; URAO. This is a hydrous sodium carbonate, corresponding to the for- mula Na 2 CO 3 .HNaCO 3 + 2H 2 O, = carbon dioxide, 38.9 per cent; soda, 41.2 per cent; water, 19.9 per cent. Found in nature as an efflorescence or incrustation from the evaporation of lakes, particularly those of arid regions. W. P. Blake has recently described 1 crude carbonate of soda (Trona) occurring in the central portion of a basin-shaped depression or dry lake in southern Arizona, near the head of the Gulf of California. The deposit covers an area of some 60 acres to a depth of from i to 3 feet, the lower portion being saturated with water from a solution so strong that when exposed to the air soda is deposited at the rate of an inch in thickness for every ten days. In its native condition the soda is naturally somewhat impure, from silt blown in from the surrounding land. The analysis given below shows the general average: Sand, silt, etc 13.00 Iron oxides and alumina 2 .80 Lime 1.14 Salt (Nad?) 4.70 Sulphate of soda 4-7 Carbonate of soda 73-66 100.00 See further under Thernardite, p. 336. VI. SILICATES. I. FELDSPARS. The name feldspar is given to a group of minerals resembling each other in being, chemically, silicates of aluminum with varying amounts of lime and the alkalies potash and soda. All members of the group have in common two easy cleavages whereby they split with even, smooth, and shining surfaces along planes inclined 1 Engineering and Mining Journal, LXV, 1898, p. 188. SILICATES. 161 to one another at angles of nearly if not quite 90. They vary from transparent through translucent to opaque, the opaque form being the more frequent. In colors they range from clear and colorless through white and all shades of gray to yellowish, pink, and red, more rarely greenish. On prolonged exposures to the weather they become whitish and opaque, gradually decomposing into soluble carbonates of lime and the alkalies, and soluble silica, any one of which may be wholly or in part removed by percolating waters, leaving behind a residual product, consisting essentially of hydrous silicates of alu- mina, to which the names kaolin and clay are given (see p. 217). The hardness of the feldspars varies from 5 to 7 of Dana's scale; specific gravity 2.5 to 2.8 They are fusible only with difficulty, and with the exception of the mineral quartz are the hardest of the common light- colored minerals. From quartz they are readily distinguished by their cleavage characteristics noted above. Geolog- ically the feldspars belong to the gneisses and eruptive rocks of all ages, certain varieties being characteristic of certain rocks and furnishing important data for schemes of rock classification. Nine principal varieties are recognized which on crystallographic grounds are divided into two groups. The first, crystallizing in the mono- clinic system, including only the varieties orthoclase and hyalophane ; the second, crystallizing in the triclinic system, including micro- clinic, anorthoclase, and the albite-anorthite series, albite, oligo- clase, andesine, labradorite, and anorthite. The above-mentioned properties are set forth in the accompanying table. Constituents. Ortho- clase. Hyalo- phane. Micro- cline. Anor- thoclase Albite. Oligo- clase. Ande- sine. Labra- dorite. Anor- thile. Silica, SiO 2 . . . . Alumina. AloOa Potash, K 2 O . . Soda, Na 2 O. . . . Barium BaO. . 64.7 18.4 16.9 51-6 21.9 10. I "i'(>'.4 64.7 18.4 16.9 66.0 20.0 S-o 8.0 68.0 20. o 62.0 24.0 60.0 26.0 53-0 30.0 43-o 37-0 12.0 9.0 8.0 4.0 Lime CaO * S ' 2.56-2.7 6.0-7.0 * 7-0 2.6-2.7 5 . 0-6 . o 13-0 2.6-2.7 6.0 20.0- 2.6-2.8 6.0-7.0 Specific grav. . . Hardness Crystalline sys- tem 2.4-2.6 6.0-6.5 2.8 6.0-6.5 2.4-2.6 6 . 0-6 . 5 2.0-5.8 2.5-2.6 6 . 07 . o Monoclinic. Triclinic. Of the above those which most concern us here are the potash feldspars orthoclase and microcline, two varieties which for our pur- l6s THE NON-METALLIC MINERALS. poses are essentially identical both as regards composition and general physical properties as well as mode of occurrence. Indeed, although crystallizing in different systems they are as a rule indis- tinguishable but by microscopic means or by careful crystallo- graphic measurements. Occurrence. The feldspars are common and abundant constitu- ents of the acid rocks such as the granites, gneisses, syenites the orthoclase and quartzose porphyries, and the Tertiary and modern lavas such as trachyte, phonolite, and the liparites. Among the older rocks they not infrequently occur in large veins or dike-like masses of coarse pegmatitic crystallization, the indi- vidual crystals being in some cases a foot or more in diameter. The associated minerals are quartz and white mica, with beryl, tourmaline, garnet, and a great variety of rarer minerals. The ordinary white mica of. commerce comes from deposits of this nature and often the two minerals are mined contemporaneously. Such of our feldspars as have yet been worked for economic purposes occur associated only with the older rocks the granites and gneisses of the Archean and Lower Paleozoic formations. Near Topsham, Maine, is one of these pegmatitic veins, running parallel with the strike of gneissoid schists in which it lies, i.e., northeast and southwest. The vein material is quartz, feldspar, and mica. The quarry, as described by R. L. Packard, is in the form of an open cut in the hillside, being some 300 feet long by 100 feet wide, and of very irregular contours. The present floor and the sides of the cut are of feldspar, containing irregular bodies of quartz and mica, the first named occurring in large masses entirely free from other minerals, though a second grade is taken out which is in reality an intimate mixture of quartz and feldspar. The quartz occurs, besides as mentioned above, in the form of irregular bodies, sometimes 6 or 8 feet across and 15 feet or more long. It also occurs in cavities, or geodes, in the form of flattened crystals. The mica is here of little economic importance, being found in the mass of the feldspar and along the seams in the form of narrow, lanceolate masses, often arranged in small radiating con- ical forms with their apexes outward. It should be noted that the rock pegmatite, a coarse pegmatitic SILICATES. 165 aggregate of quartz and feldspar, is often mined and utilized for pottery, as is the pure feldspar itself. Albite when occurring with the orthoclase is also mined and utilized in the same manner. The principal feldspar quarries thus far worked are in the eastern United States, from Maine to New Jersey. The material is mined from open cuts, being blasted out with powder and separated from adhering quartz, mica, and other minerals by hand, after which it is shipped in the rough to the potteries, or in some cases ground and bolted in the near vicinity. In Connecticut the material has in times past been ground by huge granite disks mounted like the wheels of a cart on an axle through the center of which extended a vertical shaft. By the slow revolution of this shaft the wheels travelled around in a limited circle over a large horizontal granite slab. The pieces of spar being placed upon the horizontal slab are thus slowly ground to powder, after which it is bolted and sacked. A more modern method of pulverizing is by means of the so-called Cyclone crusher. The value of the uncrushed material delivered at the potteries is but a few dollars a ton. Hence, while there are unlimited quantities of the material in different parts of the Appa- lachian region, but few are so situated as to be profitably worked. Uses. The feldspars are used mainly for pottery, being mixed in a finely pulverized condition with the kaolin or clay. When subjected to a high temperature the feldspar fuses, forming a glaze and at the same time a cementing constituent. There are other substances more readily fusible which are utilized for this purpose in the cheaper kinds of ware, but it is stated that in the highest grades of porcelain, as those of Sevres, feldspar is the material used. The proportions used vary with different manufacturers, each having adopted a formula best adapted for his own workings. 2. MICAS. Under this head are comprised a number of distinct mineral species, alike in crystallizing in the monoclinic system and having a highly perfect basal cleavage, whereby they split readily into thin, translucent to transparent, more or less elastic sheets. Chemically they are in most cases orthosilicates of aluminum with potassium and hydrogen, and in some varieties magnesium, ferrous and i6 4 THE NON-METALLIC MINERALS. ferric iron, sodium, lithium, and more rarely barium, manganese, titanium, and chromium. Seven species of mica are commonly recognized, of which but three have any commercial value, though a fourth form, lepidolite, may perhaps be utilized as a source of lithia salts. Of these three forms the white mica, muscovite, and the pearl-gray phlogopite are of greatest importance, the black variety, biotite, being but little used. Muscovite, or potassium mica, is essentially a silicate of aluminum and potassium, with small amounts of iron, soda, magnesia, and water. Its color is white to colorless, often tinted with brown, green, and violet shades. When crystal- lized it takes on hexagonal or diamond-shaped forms, as do also phlogopite and biotite. Its industrial value lies in its great power of resistance to heat and acids, its transparency, and its wonderful fissile property, in virtue of which it may be split into extremely thin, flexible sheets. It has been stated, though I know not how correctly, that sheets but one two-hundred-and-fifty-thousandth (jnprVinr) of an inch in thickness have been obtained. Phlogopite, or magnesian mica, differs from muscovite in being of a darker, deep pearl-gray, sometimes smoky, often yellowish, brownish red, or greenish color. Biotite, or magnesia iron mica, differs in being often deep, almost coal-black and opaque in thick masses, though translucent and of a dark-brown, yellow, green, or red color in thin folia. It further differs from the preceding in that its folia are less elastic, and the sheets of smaller size. Lepidolite, a lithia mica, is much more rare than either of the above, is of a pale rose or pink color, folia usually of small size, commonly occurring in scaly gran- ular forms without crystal outlines. The following table will serve to show the varying composition of the four varieties mentioned: Variety. Si0 2 . A1 2 O 3 . Fe 2 O 3 . FeO. MgO. CaO. K 2 O. Na 2 0. F. H 2 0. Muscovite 45-71 36.57 1.19 1.07 0.71 0.46 9.22 0.79 0.12 4-83 44-48 35-70 1.09 1.07 Trace. O . IO 9-77 2.41 0.72 5-50 45-40 33-66 2.36 1.86 8-33 1.41 0.69 5-46 Phlogopite 39 . 66 1 7 . oo o . 27 o . 20 26 . 49 9 . 97 o . 60 2 . 24 43-oo 13-27 1. 71 27.70 10.32 0.30 5.67 0.78 40.64 14.11 2.28 o . 69 27.97 8.16 1.16 0.82 3-21 Biotite . 31 . 69 4 75 3 90 8.00 o 59 o . 93 3 85 34- 67 30 . 09 2 . 42 16 . 99 1.98 7-55 i .57 0.28 4.64 39-30 16.95 0.48 8.45 21.89 0.82 7-79 0.49 0.89 4.02 Lepidolite 40. 1 6 50. 3Q 15-79 28. 19 2-53 4.12 26.15 5-o8 Li 2 6 7.64 12. 34 0-37 5- 15 3-58 2.36 49.62 27.30 0-31 o . 07 4-34 Li 2 11.19 2. 17 5-45 1-52 SILICATES. 165 Although the basal cleavage which permits of the ready splitting of the mica into thin sheets is the only one sufficiently developed to be of economic importance, the mica as found is often traversed by sharp lines of separation, called gliding planes, which may, by their abundance, be disastrous to the interests of the miner. Such partings, or gliding planes, supposed to be induced by pressure, are developed at angles of about 66J with the cleavage, and may cut entirely through a block or extend inward from the margin only a short distance and come to an abrupt stop. In many cases the mica is divided up into long narrow strips, from the breadth of a line to several inches in thickness, with sides parallel, and as sharply cut as though done with shears. The imperfections in mica are due to inclosures of foreign min- erals, as flattened garnets, to the presence of free iron oxides, often with a most beautiful dendritic structure, to the partings or gliding planes noted above, and to crumplings and V-like striations which destroy its homogeneity. Occurrence. Mica in quantity and sizes to be of economic importance is found only among the older rocks of the earth's crust, particularly those of the granite and gneissoid groups. Musco- vite and biotite are among the commonest constituents of siliceous rocks of all kinds and ages, while phlogopite is more characteristic of calcareous rocks. It, is, however, only when developed in crystals of considerable size in pegmatitic and coarsely feldspathic veins, or, in the case of phlogopite, in gneissic and calcareous rocks asso- ciated with eruptive pyroxenites, that it becomes available for eco- nomic purposes. The associated minerals are almost too numerous to mention. The more common for muscovite are quartz and potash feldspar, which form the chief gangue materials in crystals and crystalline masses, sometimes a foot or more in diameter. With these are almost invariably associated garnets, beryls, and tour- malines, with more rarely cassiterite, columbite, apatite, fluorite, topaz, spodumene, etc. Indeed, so abundant are, at times, the accessory minerals in the granitic veins, and so. perfect their crystal- line development, that they furnish by far the richest collecting grounds for the mineralogists. Of these minerals the quartz and 1 66 THE NON-METALLIC MINERALS. feldspars are not infrequently mined contemporaneously with the mica and utilized in the manufacture of pottery and abrasives. Origin. The origin of these pegmatitic veins is a matter of con- siderable doubt. The finer-grained pegmatites are, in certain cases, undoubted intrusives, though to some authorities it seems scarcely possible that the extremely coarse aggregates of quartz, feldspar, and mica, with large garnets, beryls, and tourmalines, can be a direct result of cooling from an igneous magma. To such it seems more probable that they are portions of an original rock mass altered by exhalations of fluorhydric acids, like the Saxon " greisen." Others regard them as resulting from the very slow cooling of granitic material injected in a pasty condition, brought about by aqueo- igneous agencies, into rifts of the preexisting rocks. It must be remembered that the high degree of dynamic metamorphism which these older rocks have undergone renders the problems relating to their origin extremely difficult. Localities. From what has been said regarding occurrences, it is evident that mica deposits are to be looked for only in regions occupied by the older crystalline rocks. In the United States, therefore, we need only look for them in the States bordering im- mediately along the Appalachian range and in the Granitic areas west of the front range of the Rocky Mountains. 1 In the Appa- lachian region south of Canada mica mines, worked either for mica alone or for quartz and feldspar in addition, have from time to time been opened in various parts of Maine. New Hampshire, Connecticut, Maryland, Virginia, North Carolina, and perhaps other States, but in none of them, with the exception of New Hamp- shire and North Carolina, has the business proven sufficiently lucrative to warrant continuous and systematic working. Indeed, were it not for the increased demand lately arising for the use of mica in electrical machines it is doubtful if any but the most favorably situated mines would remain longer in operation in the United States. This for the reason not so much that foreign mica is better as that it is cheaper. In Maine muscovite has been mined in an intermittent manner l The region of the Black Hills of South Dakota is an important exception. SILICATES. 167 along with quartz and feldspar at the well-known mineral localities at Paris Hill and Rumford, Oxford County; Auburn, Androscoggin County ; Topsham, Sagadahoc County ; Edgecomb, Lincoln County, and other counties in the southeastern part of the State. In New Hampshire the industry has assumed greater importance. The mica-bearing belt is described by Prof. C. H. Hitchcock as usually about 2 miles in width, and extending from Easton, in Grafton County, to Surry, in Cheshire County; being best developed about the towns of Rumney and Hebron. The mica accurs in immense coarse granite veins in a fibrolitic mica schist of Montalban Age, and is found in sheets sometimes a yard in length, but the more common sizes are but 10 or 12 inches in length. Immense beryls, sometimes a yard in diameter, and beautiful large tourmalines occur among the accessory, minerals. Mines for mica were opened at Grafton as early as 1840, and as many as six or eight mines have been worked at one time, though by no means continually. Other mines have been worked in Groton, Alexandria, Grafton, and Alstead, in Grafton County; Acworth and Springfield, Sullivan County; Marlboro, Cheshire County; New Hampton, Belknap County, and Wilmot, Merrimack County. As seen by the present writer, in 1894 the veins at the latter place cut sharply across the fibrolitic schist, and though the vein materials adhere closely to the wall rock on either side, without either selvage or slickensides, still the line of demarcation is per- fectly sharp. There seems no room for doubt but that the vein material was derived by injection from below, though from their extremely irregular and universally coarsely crystalline condition we must infer that the condition of the injected magma was more in the nature of solution than fusion, as the word is ordinarily used,' and also that the rate of cooling and consequent crystallization was very slow. The feldspars not infrequently occur in huge crys- talline masses several feet in diameter, though sometimes more finely intercrystallized with quartz in the form known at pegmatite. The mica is by no means disseminated uniformly throughout the vein, but on the contrary is very sporadic, and the process of mining consists mereiy in following up the mineral wherever indications as shown in the face of the quarry are sufficiently promising. Most 1 68 THE NON-METALLIC MINERALS. of the mines are in the form of open cuts and trenches, though in a few instances underground cuts have been made for a distance of a hundred feet or more. The mica blocks as removed are of a beautiful smoky-brown color, and often show a distinct zonal structure, indicating several periods of growth. The associated feldspar is not in all cases orthoclase, but, as at the Alexandria mines, sometimes a faint greenish triclinic variety. In Connecticut some mica (muscovite) has been obtained in connection with the work of mining feldspar and quartz in and about the towns of Haddam, Glastonbury, and Middletown, but the business has never assumed any importance. Mica mines have also been worked in Montgomery County, Maryland. South of the glacial limit mica mining has proven more successful from the reason that the gangue minerals (feldspar and quartz) were in a state of less compact aggregation, due to weathering, the feldspar being often reduced to the state of kaolin, and hence readily removed by pick a*d shovel. The following account of the deposits of North Carolina is given by Prof. W. C. Kerr: 1 " I have stated elsewhere, several years ago, that these veins were wrought on a large scale and for many ages by some ancient peoples, most probably the so-called Mound Builders; although they built no mounds here, and have left no signs of any permanent habitation. They opened and worked a great many veins down to or near water level; that is, as far as the action of atmospheric chemistry had softened the rock so that it was workable without metal tools, of the use of which no signs are apparent. Many of the largest and most profitable of the mines of the present day are simply the ancient Mound Builders' mines reopened and pushed into the hard undecomposed granite by powder and steel. Blocks of mica have often been found half embedded in the face of the vein, with the tool-marks about it, showing the exact limit of the efficiency of those prehistoric mechanical appliances. As to the geological relations of these veins, they are found in the gneisses and schists of the Archaean horizons. . . . These rocks are of very extensive occurrence in North Carolina, constituting in fact the great body of 1 Transactions of the American Institute of Mining Engineers, VIII 1880, p. 457. SILICATES. 169 1 70 THE NON-METALLIC MINERALS. the rocks throughout the whole length of the State some 400 miles east and west being partially covered up, and interrupted here and there by belts of later formation. Mica veins are found here, in fact may be said to characterize this horizon everywhere, from its eastern outcrop, near the seaboard, to and quite under the flanks of the Smoky Mountains. It is, however, in the great pla- teau of the West, between the Blue Ridge and the Smoky, that the mica veins reach their greatest development, and have given rise to a very new and profitable industry new, and at the same time very old. " It may be 'Stated as a very general, almost universal fact, that the mica vein is a bedded vein. Its position (as to strike and dip) is dependent on and controlled by, and quite nearly conformable to, that of the rocks in which it occurs, and hence, as well as on account of their great size, some observers, accustomed to the study of veins and dikes and the characters of intrusive rocks in other regions, have been disposed to question the vein character of these masses at first. But a good exposure of a single one of them is generally sufficient to remove all doubt on this score. The mica vein is simply and always a dike of very coarse granite. It is of any size and shape, from a few inches generally a few feet to many rods (in some cases several hundred feet) in thickness, and in length from a few rods to many hundred yards, extending in some cases to half a mile or more. The strike, like that of the inclosing rocks, is generally northeast, and the dip southeast, at a pretty high angle; but they are subject, in these respects, to many and great local varia- tions, all the conditions being occasionally changed, or even re- versed. An idea may be formed of the coarseness of these veins from this statement, that the masses of cleavable feldspar and of quartz (limpid, pale yellow, brown, or more generally, slightly smoky), and of mica, are often found to measure several yards in two or three of their dimensions, and weighing several tons. I have a feldspar crystal from one of these mines of nearly a thousand pounds' weight, and I have known a single block of mica to make two full two-horse wagon-loads, and sheets of mica are sometimes obtained that measure 3 and 4 feet in diameter. " There are many peculiarities about these veins. Among the SILICATES. 171 most important, in a practical sense, is the arrangement of the different constituents of the vein inter se. Sometimes the mica, for example, will be found hugging the hanging- wall; sometimes it is found against both walls ; again, it may be distributed pretty equally through the whole mass of the vein; sometimes, again, it will be found collected in the middle of the vein; in other cases, where the vein varies in thickness along its course, the mica will be found in bunches in the ampullations, or bellies, of the vein; in still other cases, where the vein has many vertical embranchments, the mica will be found accumulated in nests along the upper faces of these processes or offshoots. Those features of structure will be best understood from a few representative diagrams. " Fig. 19 is a horizontal section, with several transverse vertical sections of a typical vein in Yancey County, at the Presnel Mine. The length of the section, i.e., of the portion of the vein that has been stripped, is 125 feet; the thickness varies from 3 to 10 feet, except at a few points, as be, where it is nearly 20 feet. " The crystals of mica are found in this mine generally near the foot wall, in the recesses or pouches ; at c, however, as seen in section D, it is found next the hanging- wall. ; ' The inclosing rock in this case is a hard, gray slaty to schistose gneiss. . . . " The feldspar, which constitutes the larger part of the- mass of these veins, is often found converted into beds of the finest kaolin; and, curiously enough, this was one of the first and most valuable exports to England in the early part of the seventeenth century, ( packed' by the Indians out of the Unaka (Smoky) Mountains, and sold under the name 'unakeh' (white). This kaolin, like the mica, will doubtless soon come again into demand, after lying forgotten for generations." In Alabama, along a line stretching from Chilton County, north- east, through Coosa, Clay, and Cleburne counties, there are numer- ous evidences of prehistoric mica mining. Many pits are met with around which pieces of mica are still to be seen. In some places, just as in Mitchell County, North Carolina, large pine trees have grown up on the debris, so that a considerable time must have elapsed since the mines were worked. About ten years ago, Col. 172 THE NON^METALLIC MINERALS. James George, of Clanton, Chilton County, prospected for mica, and some fairly good specimens were obtained, but the investiga ions were not continued. It is not thought that any mica has been marketed from Alabama. The indications of good mica along the line mentioned are, however, sufficient to warrant additional and more extended examinations. Little mica is reported from other Southern States, though some mines have been opened in South Carolina, Georgia, Virginia, and West Virginia. In 1881 a mica mine was opened in Anderson County, South Carolina, and some miners from Mitchell County, North Carolina, employed. The enterprise was not successful, and the miners returned home shortly afterwards. Good mica has been found in South Carolina, notably in Anderson, Oconee, and Pickens counties. The mica- bearing rocks of western North Carolina do not protrude into Tennessee, except at intervals, and then only for short distances. Some pros- pecting has been done in Tennessee near Roan Mountain, but the results were not considered satisfactory. 1 In Colorado mica has long been known to be widely disseminated and to occur in many places in bodies of workable size, but mining has until lately always proved the mica to be plumose and unfit for cutting into sheets. Many mines have been located, but the product has always proved worthless, until in the summer of 1884 the Denver Mica Company opened a mine near Turkey Creek, about 35 miles from Denver. This mica is of fair quality, and quite a considerable quantity of it has been mined. It is slightly brown, and the largest plates which have yet been cut are not more than 2j by 6 inches in size. Only an extremely small percentage of the gross weight is available for cutting into sheets. An effort has been made to put it upon the market, but the industry has not vet assumed great importance. Mica of good quality and in large plates has also been recently reported from the neighborhood of Fort Collins. In Wyoming mica has been found in workable quantities near Diamond Park and in the Wind River country, as well as at many points along the mountain ranges in Laramie County. It has recently 1 Mineral Resources of the United States, 1887, p. 671. SILICATES. 173 been mined to some extent at Whalen canon, 20 miles north of Fort Laramie, and some of trie product has been shipped to the Eastern market. In New Mexico mica occurs near Las Vegas, and reports of shipments have been published. At Petaca, the Cribbenville mica mines are being worked at present by sixteen men. Work was commenced at these mines July 2, 1884, and the amount of excava- tion at present is 13,160 cubic feet. The plates cut range from 2 by 2 inches to 5 by 8 inches in size. Some specimen plates have been cut 10 by 12 inches, but the general average is about 3^ by 4^ inches. Some 12 tons of mica have been handled, but the amount sold and the average price obtained are not reported. Other localities in New Mexico also yield mica, but none have been developed, except the two above mentioned. In California many deposits of mica have been noted, especially at Gold Lake, Plumas County; in Eldorado County; Ivanpah district, San Bernardino County; near Susanville, Lassen County, and at Tehachapi pass, Kern County. In 1883 a large deposit was discovered in the Salfrion Mountains, in the northwestern part of the State, and some prospecting was done. 1 The mica-bearing deposits of the Black Hills of South Dakota have been variously regarded by different observers as intrusive granites or true segregation veins lying parallel to the apparent bedding. Newton and Jenny, 2 Blake, 3 and Vincent regard them as intrusive, while Carpenter 4 and Crosby 5 hold the opposite view. According to Blake the mica occurs in granitic masses, remark- able for the coarseness of their crystallization, the constituent min- erals being usually large and separately segregated. " Large masses of pure quartz are found in one place and masses of feldspar in another, and the mica is often accumulated together instead of being regularly disseminated through the mass. It also occurs in large masses- or crystals, affording sheets broad enough for cutting into 1 Mineral Resources of the United States, 1883-84, p. 911. 2 Geology of the Black Hills of Dakota, Monograph, U. S. Geological Survey, 1880. 3 Engineering and Mining Journal, XXXVI, 1883, p. 145. 4 Transactions of the American Institute of Mining Engineers, XVII, 1889, p. 570. Proceedings of the Boston Society of Natural History, XXIII, 1884-88, p. 488. 174 THE NON-METALLIC MINERALS. commercial sizes." Associated with the mica at this point are the minerals quartz and feldspar, mainly a lamellar albite (Clevelandite) , which form the gangue, and irregularly disseminated cassiterite (tinstone), gigantic spodumenes, black tourmalines, and, in small quantities, block mica, beryls, garnets, columbite, an.l a variety of phosphatic minerals, such as apatite, triphylite, etc. In Nevada mines have been worked in the St. Thomas mining district, Lincoln County, the mica occurring in hard, glassy quartz rock forming an outcrop some 200 feet wide by 600 feet long in gneiss and schists. At the Czarina Mine, located in May, 1891, near Rioville, the mica occurs under similar conditions. The mineral seems to follow the division plane of the stratification, along the line or axis of fold. This line runs north and south, slightly east of north of the main trend of the range, thus running into Arizona a few miles north of Rioville. In fact the mica belt forms the boun- dary line between Nevada and Arizona for 50 miles. The mica, mostly small, is abundant, but marketable sizes are rare, and not to be had without a great deal of hard work. 1 Merchantable mica has been reported on the Payette River and Bear Creek, in the Cceur d'Alene region of Idaho, and also in Oregon and Alaska. According to Mr. R. W. Ells 2 the Canadian micas of commercial importance occur associated with eruptive dikes of pyroxenite and pegmatite cutting the Laurentian gneisses. More rarely, as in the Gatineau area, they are found where dikes of the pyroxenite cut the limestone. This authority gives the condition of occurrence as below : " i. In pyroxene intrusive rocks which either cut directly across the strike of grayish or other colored gneisses or are intruded along the line of stratification. Some of these deposits have been worked downward along the contact with the gneiss, where the mica is most generally found, for 250 feet, as at the Lake Girard Mine, and irregular masses of pink calcite are abundant. In certain places apatite crystals occur associated with the mica, but at other times 1 Mineral Resources of the United States, 1893, p. 754. 3 Bulletin of the Geological Society of America, V, 1894, p. 484. SILICATES. 175 these are apparently wanting. As in the case of apatite deposits, mica occurring in this condition would apparently be found at almost any workable depth. " 2. In pyroxene rocks near the contact of cross-dikes of diorite or feldspar, the action of which on the pyroxene has led to the forma- tion of both mica and apatite. Numerous instances of this mode of occurrence are found, both in the mines of apatite and mica, the deposits of the latter in certain areas being quite extensive and the crystals of large size. " 3. In pyroxene rock itself distinct from the contact with the gneiss. In these cases the mica crystals, often of large size but frequently crushed or broken, apparently follow certain lines of faults or fracture. Some of these deposits can be traced for several yards, but for the most part are pockety. Some of these pyroxene masses are very extensive, as in the case of the Cascade Mine on the Gatineau River and elsewhere in the vicinity. In these cases calcite is rarely seen and apatite is almost entirely absent. When cut by cross-dikes conditions for the occurrence of mica or apatite should be very favorable. " 4. Dikes of pyroxene, often large, cutting limestone through which subsequent dikes of diorite or feldspar have intruded, as in Hincks township. The crystals occurring in the pyroxene near tc the feldspar dikes are often of large size and of dark color, resembling in this respect a biotite mica. " The mica found under the conditions stated above, in i, 2, 3, and 4, is all amber colored and of the variety known as phlogo- pite, or magnesia mica. "5. In feldspathic-quartzose rocks which constitute dikes often of very large size, cutting red and grayish gneiss, as at Villeneuve and Venosta. These are distinct from the smaller veins of peg- matite which occur frequently in the gneiss as the anorthosite areas are approached. In this case the mica is muscovite or potash mica and is invariably found in that portion of the dike near the contact with the gneiss. The crystals frequently are of large size and white in color, associated with crystals of tourmaline, garnet, etc., but with no apatite, unless pyroxene is also present. "6. In quartz-feldspar dikes cutting crystalline limestone, in 1 76 THE NON-METALLIC MINERALS. which case the crystals are generally of small size, mostly of dark color and of but little value. " In the case of the amber micas this peculiarity was noted: that when the pyroxene was of a light shade of greenish gray and com- paratively soft, the mica was correspondingly light colored and clear, and in some places almost approached the muscovite in general appearance. As the pyroxene became darker in color and harder in texture, the mica assumed a correspondingly darker tint and a brittle or harder character, and in certain cases where -dikes of blackish hornblendic diorite were present the mica also assumed a black color as well." The chief Canadian localities, as given by the authority quoted, are as below: " Along the Ottawa River it is found from a point nearly 100 miles west of Ottawa to the township of Greenville, 60 miles east of that city, while on the Gatineau River, which flows into the Ottawa at the city of Ottawa, mines have been located and worked for 80 miles north from its mouth, and the mineral is reported from points many miles farther north along that stream. To the east of Quebec it is known on the branch of the Saguenay called the Manouan and in the townships of Escoumains, Bergeronnes, and Tadoussac ? situated east of the mouth of that river, as well as at several other places along the river St. Lawrence. The mica found in this last district is chiefly muscovite. " The principal areas where mica is at present worked are in the belt which extends from North Burgess, in the province of Ontario, approximately along the strike of the gneiss into the terri- tory adjacent to the Gatineau and Lievre. Over much of this area south of the Ottawa River the Laurentian is concealed by the mantle of Cambro- Silurian rocks belonging to the Ottawa River basin, but it may be said that the geologic conditions and the stratigraphic sequence in the area south of the Ottawa and in the rear of Kingston are the same as those found in the mineral- bearing belts north of the Ottawa, and that the most favorable con- ditions under which the deposits of mica and apatite may be looked for are where traces of igneous agency are visible in the presence of dikes of pyroxene and quartz feldspar, though it should be stated SILICATES. 177 that the mere occurrence of these in the gneiss does not warrant the presence of either of these minerals." The India mica mines occur in coarse intrusive pegmatitic- granite dikes, cutting what is known as the newer gneiss of Singrauli. At Inikurti the crystals (of mica) are as much as 10 feet in diameter. Sheets 4 or 5 feet across have been obtained free from adventitious inclusions which would spoil their commercial value. 1 Black mica (biotite, lepidomelane, etc.) is a much more common and widely distributed variety than the white, but unlike the latter is found not so much in veins as an original constituent dissem- inated in small flakes throughout the mass of eruptive and meta- morphosed sedimentary rocks. The small sizes of the sheets, their color, and lack of transparency render the material, as a rule, of little value. In Renfrew County, Canada, the mineral occurs in large cleavable masses, which yield beautiful smoky-black and greenish sheets sufficiently elastic for industrial purposes. Lepidolite. This variety of mica is much more rare than any of the others described. While in a few instances it has been reported as accompanying muscovite in certain granites, as those of Elba and Schaistausk, its common form of occurrence is in the coarse pegmatitic veins already described, where it is associated with muscovite, tourmalines, and other minerals of similar habit- As a rule it is readily distinguished from other micas by its beautiful peach-blossom red color, though sometimes colorless and to be distinguished only by the lithia reaction. 2 The folia are thicker than those of muscovite and of small size, the usual form being that of a scaly granular aggregate. At Auburn, Maine, it is found both in this form and forming a border a half inch, more or less, in width about the muscovite folia. The more noted localities in the United States are Auburn, Androscoggin County ; Hebron, Paris, Rumford, and Norway, Oxford County, Maine, where it is asso- ciated with beautiful red and green tourmalines and other interest- ing minerals; Chesterfield, Massachusetts; Haddam, Connecticut; 1 Geology of India, 2d ed., 1893, p. 34. 2 The pulverized mineral when moistened with hydrochloric acid and held on a wire in the flame of a lamp imparts to the flame a brilliant lithia-red color. 1 78 THE NON-METALLIC MINERALS. the Black Hills, South Dakota; and near San Diego, California. The most noted foreign locality is Zinnwald, Saxony, where the mineral occurs in large foliated masses together with quartz form- ing the gangue minerals of the tin veins. Also found in Moravia. (See further under Spodumene, p. 196.) Uses. Until within a few years almost the only commercial use of mica was in the doors or windows of stoves and furnaces, the peepholes of furnaces and similar situations where transparency and resistance to heat were essential qualities. To a less extent it was used in lanterns, and, it is said, in the portholes of naval vessels, where the vibrations would demolish the less elastic glass. In early days it was used to some extent for window panes, and is, in isolated cases, still so used to some extent. For all these purposes the white variety muscovite is most suited. For use in stoves and furnaces the mica is generally split into plates varying from about one-eighth to one sixty-fourth of an inch in thickness. In preparing these plates for market the first step is to cut them into suitable sizes. Women are frequently employed in this work, and do it as well as, if not better than, the men. The cutter sits on a special bench which is provided with a huge pair of shears, one leg of which is firmly fixed to the bench itself, while the movable leg is within convenient grasp. The patterns according to which the mica is cut are arranged in a case near at hand. They are made of tin, wood, or pasteboard, according to the preference of the establishment. Generally they are simple rectangles, varying in size from about four to eighty square inches. The cutter selects the pattern which will cut to the best advan- tage, lays it on the sheet of mica, and then, holding the two firmly together, trims off the edges of the mica to make it correspond to the pattern. The cleaning process comes next. The cleaner sits directly in front of a window and must examine each sheet of cut mica by hold- ing it up between her eyes and the light. If there be any imper- fections, and there nearly always are, they must be removed by stripping off the offending layers of mica until a clear sheet remains. Finally, the cut and cleaned mica is put up in pound packages SILICATES. 179 and is ready for the market. There is an enormous waste in the processes of preparation. One hundred pounds of block mica will scarcely yield more than about fifteen pounds of the cut material, and sometimes even less. The proportion varies, of course, with different localities. 1 Professor Kerr states with reference to the North Carolina mines that there is a waste of from nine-tenths to nineteen-twentieths of the material, even in a good mine. Mica being a non-conductor is of value for insulating purposes, and since the introduction of the present system of generating electricity there has arisen a considerable demand for it in the con- struction of dynamos and electric motors. For these purposes the mica must be smooth and flexible, as well as free from spots or inequalities of any kind. It is stated that it should be sufficiently fissile to split into sheets not above three one-hundredths inch in thickness, and which may be bent without cracking into a circle of 3 inches diameter. Strips of various dimensions are used in building up the armatures, the more common sizes being about i inch wide by 6 or 8 inches long. Muscovite serves the purposes well, but is less used than phlogopite, the latter serving equally well, and being less desirable for stoves and furnaces. Black mica would doubtless serve for many purposes, could it be procured in sheets of sufficient size. Mica scraps such as until within a few years have been thrown away as worthless are now utilized by grinding, the product being used for a variety of purposes, noted below. The material is, as a rule, ground to five sizes, such as will pass through sieves of 80, 100, 140, 160, and 200 meshes to the inch, respectively. The prices of the ground material vary from 5 to 10 cents a pound according to sizes. Large quantities of ground mica are used in the manu- facture of wall paper, in producing the frost effects on Christmas cards, in stage scenery, and as a powder for the hair, being sold for the latter purposes under the name of diamond powder. The so-called French " silver molding " is said to be made from ground mica. It is also used as a lubricant, and as a non-conductor for 1 Engineering and Mining Journal, LV, 1893, p. 4. i8o THE NON-METALLIC MINERALS. steam and water heating; in the manufacture of door-knobs and buttons. It is stated further that owing to its elasticity it can be used as an absorbent for nitroglycerin, rendering explosion by percussion much less likely to occur. Small amounts of inferior qualities are also mixed with fertilizers where it is claimed to be efficacious in retaining moisture. A brilliant and unalterable riica paint is said to be prepared by first lightly igniting the ground mica and then boiling in hydrochloric acid, after which it is dried and mixed with collodion, and applied with a brush. Owing to the unalterable nature of the material under all ordinary conditions, and the fact that it can be readily colored and still retain its bril- liancy and transparency, the ground mica is peculiarly fitted for many forms of decoration. Much of the ground material now produced is stated to be sent to France. The chief and indeed only use for lepidolite thus far developed is in the manufacture of the metal lithium and lithia salts. Prices. The total value of the cut mica produced annually In the United States during the past ten years has varied from $50,000 to over $360,000, while the value of the imports has varied between $5,000 and $100,000. During 1901 but 360,000 pounds of cut mica were produced, valued at $98,859. During the same period there were produced 2,171 tons of scrap mica, valued at $19,719. The price of the cut mica, it should be stated, varies with the size of the sheets, the larger naturally bringing the higher price. The average price of the cut mica, all sizes, is not far from $i a pound, while the scrap mica is worth perhaps half a cent a pound. The dealers' lists, as published, include 193 sizes, varying from ij by 2 inches up to 8 by 10 inches, the prices ranging from 40 cents to $13 a pound. For electrical work upward of 400 patterns are called for, the prices varying from 10 cents to $2.50 -a pound. 3. ASBESTOS. The name asbestos in its original sense includes only a fibrous variety of the mineral amphibole; hence it is a normal metasilicate of calcium and magnesium with usually varying amounts of iron and manganese and not infrequently smaller quantities of the alkalies. SILICATES. 181 As is well known, the amphiboles crystallize in the monoclinic system in forms varying from short, stout crystals, like common hornblende, to long columnar or even fibrous forms, to which the names actinolite, tremolite, and asbestos are applied. The word asbestos is derived from the Greek ao-fieo-ros, signifying incombus ible, in allusion to its fire-proof qualities. The name amianthus was given it by the Greeks and Romans, the word signifying undefiled, and was applied in allusion to the fact that cloth made from it could be readily cleansed by throwing it into the fire. As now used, this term is properly limited to fibrous varieties of serpentine. Owing to careless usage, and in part to ignorance, the name asbestos 1 is now applied to at least four distinct minerals, having in common only a fibrous struc- ture and more or less fire- and acid-proof properties. These four minerals are: First, true asbestos; second, anthophyllite; third, fibrous serpentine (chrysotile), and, fourth, crocidolite. The true asbestos is of a white or gray color, sometimes greenish or stained yellowish by iron oxide. Its fibrous structure is, however, its most marked characteristic, the entire mass of material as taken from the parent rock being susceptible of being shredded up into fine fibers sometimes several feet in length. In the better varieties the fibers are sufficiently elastic to permit of their being woven into cloth. Often, however, through the effect of weathering or other agencies, the fibers are brittle and suitable only for felts and other non-conducting materials. The shape of an asbestos fiber is, as a rule, polygonal in outline and of a quite uniform diameter, as shown in the illustration (Fig. 20) ; often, however, the fibers are splinter- like, running into fine, needle-like points at the extremity. The diameters of these fibers are quite variable, and, indeed, in many instances there seems no practical limit to the shredding. Down to a diameter of 0.002 mm. and sometimes to even o.ooi mm. the fibers retain their uniform diameter and polygonal outlines. Beyond this, however, they become splinter-like and irregular as above noted. The mineral anthophyllite, like amphibole, occurs in both 1 Also spelled asbestus. The termination os seems most desirable when the deri- vation of the word is considered. 182 THE NON-METALLIC MINERALS. massive, platy, and fibrous forms, the fibrous form being to the unaided eye indistinguishable from the true asbestos. Chemically this is a normal metasilicate of magnesia of the formula (Mg,Fe)SiO 3 , differing, it will be observed, from asbestos proper in containing no appreciable amount of lime. It further differs in crystallizing in the orthorhombic rather than the mono- clinic system, a feature which is determinable only with the aid of a microscope. The shape and size of the fibers are essentially the same as true asbestos. The fibrous variety of serpentine to which the name asbestos is commercially given is a hydrated metasilicate of magnesia of the formula H 4 Mg 3 Si 2 O 9 with usually a, part of the magnesia replaced by ferrous iron. It differs, it will be observed, from asbestos and anthophyllite in carrying nearly 14 per cent of combined water and from the first named in containing no lime. This mineral is in most cases readily distinguished from either of the FIG. 20. Asbestos fibers. [U. S. National Museum.] others by its soft, silk-like fibers and further by the fact that it is more or less decomposed by acids. As found in nature the material is of a lively oil- yellow or greenish color, compact and quite hard, but may be readily reduced to the white, fluffy, fibrous state by beating, hand-picking, or running between rollers. The length of the fiber is quite variable, rarely exceeding 6 inches, but of very smooth, uniform diameter and great flexibility. The mineral crocidolite, although somewhat resembling fibrous SILICATES. 183 serpentine, belongs properly to the amphibole group. Chemically it is anhydrous silicate of iron and soda, the iron existing in both the sesquioxide and protoxide states. More or less lime and magnesia may be present as combined impurities. The color varies from lav- ender-blue to greenish, the fibers being silky like serpentine, but with a slightly harsh feeling. The composition of representative speci- mens of these minerals from various sources is given in the accom- panying table. 1 Mode of occurrence and origin. Concerning the associations^ occurrence, and origin of the fibrous structure of these minerals existing literature is strangely silent. It is known that all occur in regions occupied by the older eruptive and metamorphic rocks. It is probable that in the fibrous forms the mineral is always secondary, and the fibrous structure due in part, at least, to shearing agencies; that is, to movements in the mass of a rock whereby a mineral undergoing crystallization would be compressed laterally and drawn out along a line of least resistance. It is even probable that the structure is but an extreme development of the prismatic cleavage, due to the shearing forces. This is, however, not the case with the fibrous varieties of serpentine, which undoubtedly result from crystallization in preexisting fractures, or gash veins, of the serpentinous material. The process is evidently the same as that which is seen in 'studying, under the microscope, thin sections of olivine-bearing rocks which have undergone hydration. The asbes- tos in Alberene, in Albemarle County, Virginia, occurs in thin platy masses along slickensided zones in the so-called soapstone (altered pyroxenite) of the region, the fibers always running parallel with the direction of the movement which has taken place. The same is true of the asbestos found in the magnetite mines near Blacks- burg, in Cherokee County, South Carolina, where the fibrous struc- ture is developed only along shear zones. At Alberton, Maryland, the fibrous anthophyllite occurs along a slickensided zone between a schistose actinolite rock and a more massive serpentinous or talcose rock, which is also presumably an eruptive peridotite or 1 From Notes on Asbestos and Asbestiform Minerals by George P. Merrill. Pro- ceedings of the U. S National Museum, XVIII, 1895, pp 281-292. 184 THE NON-METALLIC MINERALS. Authority. 1 "H -"E "H -"c "E T "5 -"2 cf J? . T ^ - M ? Jf |J _ _ |J| J|| ..^7 | 3 _ ^ 8 *~! 8"! 8^ 8 .S.S'o .g.g .eg PH O PH Of^ OPnO ffiffi O Q ffiffi ffiffi . I o H O-O OO O>O OO OCO OOO OO COcOOO OOO O OOO OO d bo S|1 !' Ss S!s snl !!!| S o;; ~\ 1 3^3 33 33 ^333 33 3 33 : : 35 \*\.\ i 3 Tf- fO . . . . H >3 "-vB sS-S SS ^"33x2- 33 3 S3 " - 33 M * d a ylj ii Jii II 1 nMI iiiLli X i O^j OoO c3" ^f M 00 " OCO t^-oO t^^-^O Of 1 * ^O toow O^f 6 ..oo col : :(o,ooo o.., o :, ^ , f^ _ P-< Iw" ^^ ** ' co o h j : gj ; ;;;;;;;:::: y : : ;; = (5 m ^- ' : ' :^ :^ Is ' : ' : '^ ll^ ^ : a oo cS| __ : --d^cjcS -d ^^ffi : |*g^> m* '. \ -S 1*8 M . : g 1 1| M iy| ||iy |pls||| plf 1 ||JI| w Z^ HJ ^ S tO 0? f^ a 00 O> O 0> Ov OvOO O Ov Ov Ov Cv Ov Ov Ov Ov 8Ov O 00 0-0 Ov 5 Ov tf'&s 00,0 ^ l^ 10 VO 10 CO OV C4 ON M (OTf o I i v> ^t- 0) 00 ro \O vO Ox fO Ov ro * . . . 'J 1 : : : Tt 10 to t^OO t^ t Ov tO (O i/i^O to 10 10 o. o C VQ tl 10 vo : : : : s ~ s CS Ov co 4 '. H H 10 * M M r^ . t^ M M to vO >0 tO MM 000000 O Cvl N SJ M . . tf) vO 00 Tf - \O M fO Tf 1O $$':> Z ft f) o o o o o - : | d o* TfOO H >000 NO* M fj t- 0- ts H to tO to l^ O oo 10 t-. H fO M O O : : : j : OOOOO VO 10 Tf M PI r-M oo to to 10 Ov oo 00 M 10 W to t vO NO NO O M M ^ t^f. O M M 01 U& o ' O O ; j 1 1 ^ Hj 1 ^ i|s S3 | ffiS^ Maiden, Mass Mexico South Africa Idaho Glen Urquhart, Scotland.. The Balta, Scotland Shinness, Sutherland, Scotland Portsoy, Scotland Italy Canada Victoria, British Columbia Alberton, Md 1 Q 00 0- O fo to to to to to to 00 Ov O tO to Tj- 1 86 THE NON-METALLIC MINERALS. pyroxenite. The fibration here runs also parallel with the direction of movement as indicated by the slickensided surfaces. Localities. As already stated true hornblende asbestos occurs only in regions of eruptive and metamorphic rocks belonging to the Archaean and Paleozoic formations. The same is true of anthophyllite. Fibrous serpentine occurs sporadically with the massive forms of the same rock which is, so far as known, almost invariably an altered eruptive. The three forms are therefore likely to occur in greater or less abundance in any of the States bordering along the Appa- lachian system, but are necessarily lacking in the great Interior Plains regions, reoccurring once more among he crystalline rocks of the Western Cordilleras and the Pacific coast. The principal States from which either the true asbestos or anthophyllite has been obtained in anything like commercial quantities are Massa- chusetts, Connecticut, New York, Maryland, Virginia, North Caro- lina, South Carolina, Georgia, and Alabama, though it has been reported from other Eastern as well as several of the Western States. Fibrous serpentine (chrysotile, or amianthus) occurs in small amounts at Deer Isle, Maine; in northern Vermont; at Easton, Pennsylvania; Montville, New Jersey; in the Casper Mountains of Wyoming, and in Washington. It is known also to occur in Newfoundland. The Canadian source is in a belt of serpentinous rocks extending more or less interruptedly from the Vermont line northeastward to some distance beyond the Chaudiere River. The geological horizon is that subdivision of the Lower Silurian known as the Quebec Group. The material has also been found in the Laurentian rocks of this region. " Among the principal areas of serpentine which are found at so many widely scattered points, the most easterly yet known is at a point called Mount Serpentine, about 10 miles up the Dartmouth River from its outlet in Gaspe Basin. The serpentine is here asso- ciated with limestone and surrounded by strat? of Devonian Age. Small veins of asbestos are found in the rock,bu.. not yet in quantity sufficient to be economically valuable. West of this the next ob- served is the great mass of Mount Albert, whence it extends west in a great ridge for some miles. This mass is known to contain veins of chromic iron, and traces of asbestos have also been observed, but SILICATES. 187 the area has never yet been carefully explored with a view to ascertain the presence of the mineral in quantity, owing largely to the present difficulty of access. " In Cranbourne and Ware, to the north of the Chaudiere River and in the vicinity of that stream between the villages of St. Joseph and St. Francis, several small knolls are seen, in all of which small and irregular veins are visible, but apparently not in quantity suf- ficient to render them economically important, at least in so far as yet examined. Further to the southwest, in Broughton, Thetford, Coleraine, Wolfestow, and Ham, a very great development of these rocks is observed, forming at times mountain masses from 600 to 900 feet above the surrounding country level, and presenting very peculiar and boldly marked features in the landscape by their rugged outlines and curiously weathered surfaces. The large areas of this division terminate southward at a point termed Ham Mountain, a very prominent peak of diorite which marks the ex- tremity of the ridge. In this great area, which we may style the central area, asbestos can be found at many points in small quantity, but at a comparatively few does it occur in quantity and quality sufficient to warrant the expenditure of much capital in its extraction. "The third area, regarding that of the Shickshocks as the first, begins near the village of Danville, and may be styled the south- western area. Thence it extends through Melbourne, Brompton, Orford, Bolton, and Potton, in a series of disconnected hills, to the American boundary, beyond which the continuation of the serpen- tines can be traced into Vermont. In these areas, with the excep- tion of the peculiar isolated knoll near Danville, the asbestos has, as yet, been observed in small quantity only, and generally of inferior quality. Large areas of soapstone are found at points throughout the area, and the associated diorites have a large development. It must, however, be said of this section, that considerable areas, whose outcrops can be seen along the roads which traverse the district, are concealed by a dense forest growth, and the true value of such portions must, for some considerable time, be largely con- jectural. In fact, until the forest and soil are completely removed by the action of forest fires, as was the case at Black Lake and Thet- ford, the search for asbestos is likely to prove difficult and unsatis- i88 THE NON-METALLIC MINERALS. factory. It is, however, very evident from the studies already made on this interesting group of rocks in Canada, that all serpen- tines are not equally productive a fact very evident even in the heart of the great mining centers themselves, where large areas of the belt are made up of what is known as barren serpentine. As a general rule, however, the rock likely to prove asbestos-producing can be determined by certain peculiarities of texture, color, or weather- ing. "At the Thetford mines, and in that portion of Coleraine lying to the northeast of Black Lake, certain conditions favorable to the production of asbestos appear to have prevailed, and have led to the formation of numerous veins, often of large size, which, in places, interlace the rock in all directions. These veins range in size from small threads to a width of 3 to 4 inches (Fig. 21), and FIG. 21. Serpentine asbestos in massive serpentine. [U. S. National Museum.] in rare cases even reach a thickness of over 6 inches. The quality of the fiber, however, varies even in these localities, and while much of it is soft, fine, and silky, other portions are characterized by a SILICATES. 189 harshness or stiffness which detracts greatly from its commercial value." The veins while not disturbed by faulting generally improve so far as quality of material is concerned as the depth below the surface increases. They are, however, very irregular in their dis- tribution, and are rarely persistent for any great distance. " A small vein at the surface, of half an inch in thickness, may quickly enlarge to one of 3 inches or more, and, continuing, may die out entirely, while others come in on either side. They have much the aspect of the gash veins in slaty rocks, though there are many instances seen where the fiber maintains a tolerably uniform size for considerable distances. " The containing rocks show the presence of numerous faults, as in other mineral localities, but possibly in the serpentine these are often more plainly marked. These faults throw the veins from side to side, and frequently are of sufficient extent to cut off entirely the working face of a highly productive area, the rock on the other side of the fissure being often entirely barren. The sides of the fault, in such cases, show extensive slickensides, and frequently have great sheets of coarse or woody-fibered or imperfect asbestos, along the planes of fracture. Occasionally, pockets or small veins of chromic iron are found in close proximity to the asbestos." 1 The Vermont asbestos is of the same type as the Canadian. It is found near Eden, in Lamoille County, at the adjacent town of Lowell, in Orleans County, in the northern part of the State. At Eden the mines occur in the south face of Belvidere Mountain, where a great mass of serpentine occurs intruded between a micaceous schist below and a hornblendic schist above. The serpentine occurs in the form of bold escarpments, and the mining is carried on wholly from open cuts. The veins are rarely more than three- fourths of an inch in width. At Lowell two types of material are met with, the one with fibers standing practically at right angles with the walls, as in the localities described, and the other with fibers parallel to the slickensided faces of joints. This last variety is 1 R. W. Ells, Transactions of the American Institute of Mining Engineers, XVIII, 1890, p. 322. 190 THE NON-METALLIC MINERALS. much the more brittle, and as it occurs in layers seldom more than a fourth of an inch in thickness, is much less desirable. The Italian asbestos which finds its way to the American markets is both of the amphibolic and serpentinous varieties, both being re- markable for the beautiful long fibers they yield. The amphibolic variety, the true asbestos, comes from Mont Cenis, and the serpen- tinous variety, from Aosta. Methods of mining and preparation. The mining of asbestos is carried on almost wholly from open cuts and shallow tunnels. Rarely does it pay to follow the material to any great depth. In the United States the mines are worked very irregularly, and in most cases abandoned at the end of a short season. The mining of the Canadian material is carried on by means of open cuts, much as a farmer cuts down a stack of hay or straw, or by open quarry on a level. The rock is blasted out and the asbestos separated from the inclosing rock by a process known as " cobbing," and which consists in breaking away the fibrous material from the walls of the vein or from other foreign ingredients by means of hammers. The cobbed material is separated into grades, according to quality, which depends upon the length, fineness, and flexibility of the fiber. During 1888 the finest grades brought prices varying from $80 to $110 a ton. In 1899 the price had fallen to about $26 a ton. Uses. The uses of asbestos are manifold, and ever on the increase. Among the ancient Greeks it was customary to wrap the bodies of those to be burned in asbestos cloth, that their ashes might be kept intact. In the eighth century Charlemagne is said to have used an asbestos tablecloth, which, when the feast was over, he would throw into the fire, after a time withdrawing it cleaned but unharmed, greatly to the entertainment of his guests. The most striking use to which the material is put is the manufacture of fire- proof cloths for theater curtains, for suits of firemen and others liable to exposure to great heat. It is also used for packing pistons, closing joints in cylinder heads, and other fittings where heat, either dry or from steam and hot water, would shortly destroy a less durable substance. For this purpose it is used in the form of a yarn, or as millboard. The lower grades, in which the fibers are short or SILICATES. 191 brittle, are made into a felt which, on account of its non-conducting powers, is utilized in covering steam boilers. It is also ground and made into cements and paints, the cement being used as a non- conductor on boilers, and the paint to render wooden structures less susceptible to fire. In the chemical laboratory the finely fibered, thoroughly purified asbestos forms an indispensable filtering medium. For this purpose the true asbestos is preferable to the fibrous serpen- tine. 1 In the manufacture of cloth, rope, and other materials where strength and flexibility of fiber are essential the serpentine asbestos (chrysotile) is preferable to the amphibolic form, though, owing to its hydrous condition, it is, in reality less fire-proof. Within a few years it has been found that the massive material previously considered as waste at the Danville mines could, by proper treatment, be reduced to a fibrous pulp amdirably adapted for a wall plaster, and similar uses. This material is known under the commercial name of asbestic. The chief use of asbestos is based upon its highly refractory or non-combustible nature. The popular impression that it is a non- conductor of heat is, according to Professor Donald, erroneous, the non-conducting character of the prepared material being due rather to its porous nature than to the physical properties of the mineral itself. 2 Owing to the comparatively high price of asbestos, it is, in the manufacture of the so-called non-conducting materials, largely admixed with plaster of Paris, powdered limestone, dolomite, mag- nesite, diatomaceous earth, or carbonaceous matter, as hair, paper, sawdust, etc. With the possible exception of the magnesite (carbon- ate of magnesia) these are all less effective than the asbestos, and deteriorate as well as cheapen the manufactured article. The following table will serve to convey some idea of the relative portions of the various materials used as non-conducting pipe coverings, etc.: 1 Prof. A. H. Chester: Some Misconceptions Concerning Asbestos. Engineering and Mining Journal, LV, 1893, p. 531. 2 The Mineral Industry, II, 1893, p. 4. 192 THE NON-METALLIC MINERALS. Parts. Asbestos sponge, molded: Plaster of Paris ...................... ... 95-8o Fibrous asbestos , 4.20 100.00 Fire-felt sectional covering: Asbestos 82.00 Carbonaceous matter (hair, paper, sawdust, etc.) 18.00 100.00 Magnesia sectional covering: Carbonate of magnesia .... ... ... . . . . ... ... ... ... 92 .20 Fibrous asbestos ..................... 7 .80 IOO.OO Magnesia plastic: Carbonate of magnesia .,. ... . . ... ... ... ... ... ... ... . ., 92 .20 Fibrous asbestos ,. ... ... ... ... ... . ., 7 .80 100.00 Asbestos cement felting: Powdered limestone 64.50 Plaster of Paris 3.50 Asbestos 32.00 100.00 Asbestos-sponge cement felting: Powdered limestone 59-oo Plaster of Paris 10.00 Asbestos 31.00 100.00 Fossil meal: Insoluble silicate , 75- Carbonaceous matter (hair, paper, sawdust, etc.) i i.oo Soluble mineral matter 8.00 Moisture 6.00 IOO.OO The annual amount of asbestos of all kinds produced in the United States varies from 600 to 1,000 tons, valued at about $15 per ton. Some 30,000 tons of asbestos and asbestic are produced by the Canadian mines, a considerable proportion of which finds its way into American markets. SILICATES. 193 BIBLIOGRAPHY. A. LIVERSIDGE. Minerals of New South Wales, 1888, p. 180. Gives list of localities. ROBERT H. JONES. Asbestos, Its Properties, Occurrence, and Uses. London, 1890, p. 236. L. A. KLEIN. The Canadian Asbestos Industry. Engineering and Mining Journal, LIV, 1892, p. 273. J. T. DONALD. Asbestos in Canada. The Mineral Industry, I, 1892, p. 30. L. A. KLEIN. Notes on the Asbestos Industry of Canada. The Mineral Industry, I, 1892, p. 32. J. T. DONALD. Asbestos. The Mineral Industry, II, 1893, p. 37. RUDOLF MARLOCH. Asbestos in South America. Engineering and Mining Journal, LVIII, 1894, p. 272. C. E. .WILLIS. The Asbestos Fields of Port-au-Port, Newfoundland. Engineering and Mining Journal, LVIII, 1894, p. 586. GEORGE P. MERRILL. Notes on Asbestos and Other Asbestiform Minerals. Proceedings of the U. S. National Museum, XVIII, 1895, p. 281. H. NELLES THOMPSON. Asbestos Mining and Dressing at Thetford. The Journal of the Federated Canadian Mining Institute, 1897, II, p. 273. See also the Canadian Mining Review, XVI, 1897, p. 126. ROBERT H. JONES. Asbestos and Asbestic: Their Properties, Occurrence, and Use. London, 1897, pp. 368. J. F. KEMP. Notes on the occurrence of Asbestos in Lamoille and Orleans counties, Vermont. Mineral Resources of the United States, 1901. 4. GARNET. The chemical composition of the various minerals of the garnet group is somewhat variable, though all are essentially silicates of alumina, lime, iron, or magnesia. The more common types are the lime- alumina garnet grossularite, and the iron- alumina garnet alamandite. Other varieties of value as minerals or as gems are pyrope, spessartite, andradite, bredbergite, and uvarovite. The ordinary form of the garnet is the regular 12- or 24-sided solid, the dodecahedron and trapezodedron, as shown in Fig. 22. The color is dull red or brown, though in the rarer forms yellow, green, and white. Hardness from 6.5 to 7.5 of the scale. Occurrence. Garnets occur mainly in metamorphic siliceous rocks, such as the mica schists and gneisses, and though sometimes found in limestones and in eruptive rocks, are rarely sufficiently abundant to be of economic importance. In the gneisses and schists, 194 THE NON-METALLIC MINERALS. howev r, they not infrequently preponderate over every other con- stituent, varying from sizes smaller than a pin's head to masses of 100 pounds' weight, or more. The most important garnet-producing regions of the United States are Roxbury, Connecticut, Warren County, New York, and Delaware County, Pennsylvania. At the first-named locality, the garnets occur in a mica schist; in New York they are found in FlG. 22. Outlines of garnet crystals. laminated pockets scattered through beds of a very compact horn- blende feldspar rock, the size of the pockets ranging from 5 or 6 inches in diameter to such as will yield 1,000 pounds or more. In the Delaware County localities the garnets occur in aggregates of small crystals in a quartzose gneiss. 1 One of the most noted garnet regions of the world is that near Prague, Bohemia. According to G. F. Kunz, 2 the garnets of the pyrope variety are indigenous to an eruptive rock now changed to serpentine, and the mineral is found " loose in the soil or in the lower part of the diluvium, or embedded in a serpentine rock. . . . In mining the earth is cut down in banks and only the lower layer removed, and the garnets are separated by washing. The earth is first dry-sifted and then washed in a small jig consisting of a sieve moved back and forth in a tank of water." According to Mr. D. B. Sterrett, the garnets at Roxbury, noted above, occur in the form of dodecahedrons of all sizes up to an inch and a half in diameter, embedded in a mica schist. 1 The Mineral Industry, V, 1896. 3 Transactions of the American Institute of Mining Engineers, XXI, 1892, p. 241. SILICATES. 195 The present quarry is situated upon a hilltop some three miles outside of the town of Roxbury. Mining is done wholly by open cuts. The rock is blasted out by dynamite and broken into masses suitable for handling, which are then raised from the quarry, dumped into a gravity car, and run to a crushing mill. The schist is soft, crushing easily, the garnets coming out, in large part, free from the matrix and unbroken. From the crusher pieces of all sizes up to a hen's egg fall through a chute and are scattered evenly over a broad belt, some 2 feet in width and 12 or more in length, over which small streams of water are kept playing in order to settle the dust and cleanse the garnets. On either side of this belt men are employed to pick out the garnets, which are placed upon a small belt above moving in the same direction, which carries them to the storing bins, where they are run into sacks of 100 pounds' weight each and shipped to Chicago, at which place they are utilized by the Armour Packing Company in the manufacture of the so-called emery paper. The waste at the quarry is very great, amounting, it is estimated, to from one-half to three-fourths of the entire amount mined. Uses. Aside from their uses in the cheaper forms of jewelry, garnets are used mainly for abrading purposes and mainly as a sand for sawing and grinding stone or for making sandpaper. The material is of less value than corundum or emery, owing to its inferior hardness. The commercial value is variable, but as prepared for market it is worth about 2 cents a pound. 5. ZIRCON. This is a silicate of zirconium, ZrSiO 4 , = silica, 32.8 per cent; zirconia, 67.2 per cent; specific gravity, 4.68 to 4.7; hardness, 7.5; colorless, grayish, pale yellow to brown or reddish brown. Ordi- narily in the form of square prisms (Fig. 23). Zircon is a common constituent of the older eruptives like granite and syenite, and also occurs in granular limestone, gneiss, and the schists. It is so abundant in the elaeolite syenites of Southern Norway as to have given rise to the varietal name Zircon syenite. Although widespread as a rock constituent it has been reported in but few instances in sufficient abundance to make it of commercial I 9 6 THE NON-METALLIC MINERALS. value. Being hard and very durable it resists to the last ordinary atmospheric agencies, and hence is to be found in beds of sand, gravel, and other debris resulting from the decomposition of rocks in which it primarily occurs. It has thus been reported as found in the alluvial sands in Ceylon, in the gold sands of the Ural Mountains, Australia, and other places. In the United States it occurs in considerable abundance in the elaeo- lite syenite of Litchfield, Maine, and FIG. 23. Outlines of zircon crystals. . , . . . . _. is also found in other States bordering along the Appalachian Mountains. The most noted localities are in Henderson and Buncombe counties in North Carolina, whence several tons have been mined during the past few years from granite debris. Uses. See under Monazite, p. 298. 6. SPODUMENE AND PETALITE. Spodumene. This is an aluminum-lithium silicate of the formula LiAl(SiO 3 ) 2 , = silica, 64.5 per cent; alumina, 27.4' per cent; lithia, 8.4 per cent ; in nature more or less impure through the presence of small amounts of ferrous oxide, lime, magnesia, potash, and soda. Luster, vitreous to pearly; colors, white, gray, greenish, yellow, and amethystine purple, transparent to translucent. Usual form that of flattened prismatic crystals, with easy cleavages parallel with the faces of the prism. Also in massive forms. Crystals sometimes of enormous size, as noted below. Mode of occurrence. Spodumene occurs commonly in the coarse granitic veins associated with other lithia minerals, together with tourmaline, beryls, quartz, feldspar, and mica. The chief localities as given by Dana are as below: " In the United States, in granite at Goshen, Massachusetts, associated at one locality with blue tourmaline and beryl; also at Chesterfield, Chester, Huntington (formerly Norwich), and Sterling, Massachusetts; at Windham, Maine, with garnet and staurolite; at Peru with beryl, triphylite, petalite; at Paris, in Oxford County; at Winchester, New Hampshire; at Brookfield, SILICATES. 197 Connecticut, a few rods north of Tomlinson's tavern, in small gray- ish or greenish- white individuals looking like feldspar; at Branch- ville, Connecticut, in a vein of pegmatite, with lithiophilite, uran- inite, several manganesian phosphates, etc.; the crystals are often of immense size, embedded in quartz; near Stony Point, Alexander County, North Carolina, the variety hiddenite in cavities in a gneiss- oid rock with beryl (emerald), monazite, rutile, allanite, quartz, mica, etc.; near Ballground, Cherokee County, Georgia; in South Dakota at the Etta tin mine in Pennington County, in immense crystals. At Huntington, Massachusetts, it is associated with tri- phylite, mica, beryl, and albite; one crystal from this locality was i6J inches long and 10 inches in girth." At the Etta tin mine, in the Black Hills of South Dakota, the mineral occurs, according to W. P. Blake, in sizes the magnitude of which exceeds all records. Crystalline masses extend across the face of the open cut from 2 to 6 feet in length and from a few inches to 12 and 1 8 inches in diameter. Blocks too large to lift have been freely tumbled over the dump with the waste of the feldspar, quartz, and mica. The gigantic crystals preserve the cleavage characteris- tics and show the common prismatic planes. The color is lighter and is without the delicate creamy-pink hue of the specimens from Massachusetts. It is very hard, compact, and tough, and is dif- ficult to break across the grain. Some of the fragments are trans- lucent. (See Plate XIV.) The chief foreign localities of spodumene are Uto in Sodermanland, Sweden, where it is associated with magnetic- iron ore, tourmalines, quartz, and feldspar; near Sterzing and Lisens, in Tyrol ; embedded in granite at Killiney Bay near Dublin, and at Peterhead, Scotland. Uses. Spodumene and the lithia-mica lepidolite are used in the manufacture of lithia salts, although the industry is not yet one of great importance. The price of the crude material varies with the percentage of lithium, which as noted is greatest in the first- named mineral. During the year 1901 the prices ranged from $11.00 to $40.00 per ton. the total production for the year being but 1,750 tons, derived mainly from California and in the form of lepidolite. Petalite, another lithium- aluminum silicate containing 2.5 to 5 per cent lithia occurs associated with lepidolite, tourmaline, and 198 THE NON-METALLIC MINERALS. spodumene in an iron mine at Uto, Sweden, with spodumene and albite at Peru, Maine, and with scapolite at Bolton, Massachusetts. 7. LAZURITE; LAPIS LAZULI; OR NATIVE ULTRAMARINE. Composition essentially Na 4 (I^aS 3 .Al)Al 2 Si3O 12 , = silica, 31.7 per cent; alumina, 26.9 per cent; soda, 27.3 per cent; sulphur, 16.9 per cent; hardness, 5.5; specific gravity, 2.38 to 2.45. Color, rich azure-violet or greenish blue, translucent to opaque. The ordinary la'pis lazuli is not a simple mineral as given above, but a mixture of lazurite, hauynite, and various other minerals. The following analyses quoted from Dana serve to show the heterogeneous character of the -material as found: Localities. Silica, SiO 2 . Alumina, A1 2 3 . Ferric Iron. Fe 2 O 3 . Lime, CaO. Soda. Na 2 O. Water, H 2 O. Sulphur, S0 3 - Orient 4.C.22 12. 37 2.12 23 ^6 1 1 4^ o } e 2 22 Ditr6 4O.S4 43.OO 0.86 1. 14 12 ^4 I 02 Andes 4^.70 2?. 34 i. 30 7.48 JO.C C A IV 4*3* Occurrence. The localities are mostly foreign. The ultramarine reported not long since as occurring near Silver City, New Mexico, has been shown by R. L. Packard to be a magnesian silicate. Mexico, Chile, Siberia, India, and Persia are the chief sources. The following regarding the Indian localities is taken from Ball's Geology of India, Part III. According to Captain Hutton, the lapis lazuli sold in Kandahar is brought from Sadmoneir and Bijour, where it is said to occur in masses and nodules embedded in other rocks. He obtained a small specimen from Major Lynch, which was said to have been brought from Hazara, and he heard that it occurred in Khelat. Several writers speak of its occurrence in Beluchistan. but possibly this may be due to some confusion in names. Beyond a question of doubt it does exist in Badaksham, the mines south of Firgamu. in the Kokcha valley, having been described by Wood in the narra- tive of his journey to the Oxus. The entrance to the mines is on the face of the mountain at an elevation of about 1,500 feet above the level of the stream The rocks are veined, black and white limestones. The principal mine as rep- SILICATES. 199 resented in elevation, pursues a somewhat serpentine direction. The shaft by which you descend to the gallery is about 10 feet square, and is not so perpendicular as to prevent your walking down. The gallery is 30 paces long, with a gentle descent, but it terminates in a hole 20 feet in diameter and as many deep. The gallery is 12 feet in diameter, and as it is unsupported by pillars accidents sometimes occur. Fires are used to soften the rock and cause it to crack; on being hammered it comes off in flakes, and when the precious stone is disclosed a groove is picked round it, and together with the portion of the matrix it is pried out by means of crowbars. Three varieties are distinguished by the miners, the mli, or indigo colored, the asmani, or sky-blue, and the sdbzi, or green. The labor was com- pulsory, and mining was only practiced in the winter. According to Wood, these mines and also those for rubies had not been worked for four years as they had ceased to be profitable. Possibly this may have been partly due to the fall in value; according to Mr. Baden-Powell, recent returns represent the exports as amounting to only 2 seers; but Colonel Yule, in his book of Marco Polo, states that the produce was 30 to 60 poods (36 pounds each) annually, the best qualities selling at prices ranging from 12 to 24 a pood. Mr. Powell's figures perhaps only refer to the exports to India. Formerly the produce from these mines, which must have been considerable, was exported principally to Bokhara and China, whence a portion found its way to Europe. Marco Polo says that the azure found here was the finest in the world, and that it occurred in a vein like silver. The Yamgan tract, in which the mines were situated, contained many other mines, and doubtless Tavernier referred to it when he spoke of the territory of a Raja beyond Kashmir and toward Thibet, where there were three mountains close to one another, one of which produced gold, another granats (garnets, or rather balas rubies), and the third lapis lazuli, A small quantity of lajward is said to be imported into the Punjab from Kashgar, and a mine is reported to exist near the source of the Koultouk, a river which falls into Lake Baikal. Uses Ultramarine for coloring purposes has in modern times lost much of its value, owing to the discovery by M. Guimet in 200 THE NON-METALLIC MINERALS. 1828 of an artificial substitute. Formerly it was much used as a pigment, being preferred by artists in consequence of its possessing greater purity and clearness of tint. According to Ball, 1 the artificial substitute is now commonly sold in the bazars of India under the same name, lajward, for about 4 rupees a seer, while at Kandahar in the year 1841, according to Captain Hutton, the true lajward, which was used for house painting and book illuminating, was sold, when purified, at from 80 to 100 rupees a seer. Mr. Emanuel states that the value of the stone itself, when of, good color, varies, according to size, from 10 to 50 shillings an ounce. In Europe the refuse in the manufacture is calcined, and affords delicate gray pigments, which are known as ultramarine ash. Lajward is prescribed internally as a medicine by native phy- sicians; it has been applied externally to ulcers. That it possesses any real therapeutic powers is, of course, doubtful. Although no longer a source of any considerable amount of the ultramarine of commerce, the compact varieties of the mineral, such as that from Persia, are highly esteemed for the manufacture of mosaics, vases, and other small ornaments. 8. ALLANITE; ORTHITE. This is a cerium epidote of the formula HR II R III 3 Si 3 O 1 3, in which R 11 may be either calcium or iron (or both) and R nl aluminum, iron cerium, didymium, or lanthanum. The analyses given on the next page are 'selected from Dana's Mineralogy as showing variation in the composition sufficient for present purposes. When in crystals often in long slender nail- like forms (orthite); also massive and in embedded granules. Color, pitch-black, brown- ish, and yellow. Brittle. Hardness, 5.5 to 6. Specific gravity, 3.5 to 4.2. Before the blowpipe fuses and swells up to a dark, slaggy, magnetic glass. Localities and mode of occurrence. The more common occur- rence is in the form of small, acicular crystals as an original con- stituent in granitic rocks. It also occurs in white limestone, asso- ciated with magnetic-iron ore, and in igneous rocks as andesite, diorite, 1 Geology of India, III, p. 528. SILICATES. 201 Constituents. I. II. III. Silica (SiO 2 ) 31.63 52. 03 ?o 04. Thorina (ThO 2 ) ... ... o*--"o 0.87 1. 12 None Alumina (A1 2 O 3 ) 13.21 17 63 16 10 Iron sesquioxide (Fe O ) 8 ."70 c 26 * 06 Cerium sesquioxide (Ce CO 8.67 ^.^v/ 2 84 1 1 61 Didymium sesquioxide (Di CO * 60 7 68 52Q Lanthanum sesquioxide (LaOo) S'W r.46 None 41 I Yttrium sesquioxide (Y 9 CX) .... 3~ O.87 2 Q2 None Erbinum sesquioxide (Er 2 Oo) O.t?2 None. None Iron protoxide (FeO) 7.86 7.01 o 80 IVEanganese (M^nO) . ... ............ 1.66 0.64 y.y Chinese dealers at the various expositions of late years under the name of jade stone are, however, of agalmatolite. Pinite: Agalmatolite in part. Composition, a hydrous silicate of alumina and the alkalies. According to Dana, 1 the name is made to include a large number of alteration products of white spodumene, nepheline, feldspar, etc. Professor Heddle has de- scribed 2 a pinite (agalmatolite) occurring in large lumps of a sea- green color, surrounding crystalline masses of feldspar in the granites of Scotland, and which he regards as alteration products of oligo- clase. The composition as given is : Silica, 48.72 per cent; alumina, 31.56 per cent; ferric oxide, 2.43 per cent; magnesia, 1.81 per cent; potash, 9.48 per cent; soda, 0.31 per cent; water, 5.75 per cent. 14. SEPIOLITE; MEERSCHAUM. This mineral is a hydrous silicate of magnesia, having the com- position indicated by the formula H 4 Mg 2 Si 3 O 10 ,= silica, 60.8 per cent; magnesia, 27.1 per cent; water, 12.1 per cent. The prevail- ing colors are white or grayish, sometimes with a faint yellowish, reddish, or bluish-green tinge. It is sufficiently soft to' be impressed by the nail, opaque, with a compact structure, smooth feel, and somewhat clay-like aspect; rarely it shows a fibrous structure. In 1 System of Mineralogy, 6th ed., p. 621, s Mineralogical Magazine, IV, p. 215. 2l6 THE NON-METALLIC MINERALS. nature it rarely occurs in a state of absolute purity. The following analyses are quoted from Dana's Mineralogy: Locality. SiO 2 . MgO. FeO. H 2 O. CO 2 . Turkey 61.17 28.43 O.o6 0.83 Greece 61.30 28.30 0.08 0.74 974 Utah (fibrous) C2 Q7 22.^0 j CuO. r O QO j Hygroscopic H 2 O 1 0.87 ( 8.80 The name is from the German words M eer, sea, and Schaum, foam, in allusion to its appearance. Mode oj occurrence and origin. According to J. Lawrence Smith, 1 the Asiatic material occurs in the form of nodular masses in alluvial deposits on the plain of Eski-Shehr, and is regarded by him as derived by a process of substitution from magnesium carbonate which is found in the serpentine of the neighboring moun- tains. In an article by Dr. E. D. Clarke in the Cyclopedia of Arts and Sciences it is stated that the meerschaum of the Crimeria forms a stratum some 2 feet thick beneath a much thicker stratum of mark Cleveland in his elementary treatise on minerals (1822) states that at Analotia, in Asia Minor, meerschaum occurs in the form of a vein more than 6 feet wide, in compact limestone. At Vallecas, Spain, a very impure form is stated to occur in the form of beds and in such abundance as to be utilized for building material. Aside from the localities above mentioned, sepiolite is known to occur in Greece, at Hrubschitz in Moravia, and in Morocco, in all cases being associated with serpentine, with which it is apparently genetic- ally related. According to Kunz, 2 meerschaum has occasionally been met with in compact masses of smooth, earthy texture in the serpentine quarries of West Nottingham Township, Chester County, Pennsyl- vania. Only a few pieces were found, but they were of good quality. It also occurs in grayish and yellowish masses in the serpentine in Concord, Delaware County, Pennsylvania. Masses of pure white 1 American Journal of Science, 1849, VIII, p. 285. 3 Gems and Precious Stones, p. 189. SILICATES. 217 material, weighing a pound each, have been found in Middletown, in the same county, and of equally good quality at the Cheever Iron Mine, Richmond, Massachusetts, in pieces over an inch across; also in serpentine at New Rochelle, Westchester County, New York. A fibrous variety, in masses of considerable size, has within a few years been found in the Upper Gila River region, New Mexico. Uses. The mineral owes its chief value to its adaptability for smokers' use, being utilized in the manufacture of what are known as meerschaum pipes. At Vallecas, as above noted, the material is said to occur in such abundance as to be utilized as a building stone. In Algeria a soft variety is used in place of soap at the Moorish baths and for washing linen. According to a writer in the Engineering and Mining Journal, 1 the Eski-Shehr mineral is mined from pits and horizontal galleries in much the same manner as coal. As first brought to the surface it is white, with a yellowish tint, and is covered with red clayey soil. In this condition it is sold to dealers on the spot. Before exporting the material is cleaned, dried, and assorted, the drying taking place in the open air, without artificial heat in summer, and requiring from five to six days. The bulk of the material is sent direct to Vienna and Paris. 15. CLAYS. The term clay as commonly used is made to comprise materials of widely diverse origin and mineral and chemical composition, but which have in common the property of plasticity when wet, and that of becoming indurated when dried either by natural or artificial means. Of so variable a nature is the material thus classed that no brief definition can be given that is at all satisfactory. One may perhaps describe the clays, as a whole, as heterogeneous ag- gregates of hydrous and anhydrous aluminous silicates, free silica, and ever-varying quantities of free iron oxides and calcium and magnesian carbonates, all in a finely comminuted condition. Origin and mode of occurrence. The clays are invariably of 'Volume LIX, 1895, p 464. 2l8 THE NON-METALLIC MINERALS. secondary origin that is, they result from the decomposition of preexisting rocks and minerals and the accumulation of their less soluble residues, either in place (residual clays) or through the transporting power of ice and water (drift clays). The fact that silicate of aluminum is so characteristic a constituent of nearly all clays is due to the fact that this substance is one of the most insoluble of natural compounds, and hence when, under the action of atmospheric or subterranean agencies, rocks decompose and their more soluble constituents as lime, magnesia, potash, soda, or even silica are removed, the aluminous silicate remains. The kaolins, which may be regarded as the simplest of clays, are the product, mainly at least, of the decomposition of feldspars, a form of decomposition which consists essentially of hydration and a more or less complete removal of the lime and alkalies and a part of the silica. The following tables show the composition of the common feldspars and the approximate loss and gain of material they undergo in passing into the condition of kaolin. The formula Si 2 O 9 Al 2 H 4 given is, it should be noted, that of the mineral kaolinite, of which the material kaolin is commonly regarded as an impure form. Si0 2 64.86 MA 18.20 K 2 1685 H 2 IOO OO Lost 43 24. 16 85 Taken up 64? 6 45 18.20 645 2. 'Albite Si0 2 68.81 MA 10.40 Na 2 11.70 w> ^O H 2 IOO OO Lost 4^.87 1 1 7O 57 66 Taker! up , 6 85 6 85 10.40 685 3. Anorthite Si0 2 43.^O A1 2 3 36 6"? CaO 20 07 H 2 O Lost , 2O O7 Taken up j.vf 12 Q2 Kaolinite.. 43.30 I2.O2 02.85 From this it appears that, in the case of orthoclase and albite, two-thirds of the silica and all the alkalies are removed. In all, over half of the feldspathic constituents are lost during the transi- SILICATES. 219 tion, while, in the anorthite, only the lime is carried away. The proportional loss and gain is shown as follows: Orthoclase. . Albite ...... 2 Si 3 8 AlNa - 4 SiO 2 - Na 2 O + 2 H 2 O = Si 2 O 9 A1 2 H 4 . Anorthite. . . Si 2 O 8 Al 2 Ca-CaO + In other words, two molecules of albite or orthoclase are neces- sary for the formation of one molecule of kaolin, while, in the case of anorthite, one molecule is sufficient to produce one molecule of kaolin. As to the method by which this decomposition is brought about authorities differ. It has been commonly assumed that the same was a purely superficial phenomenon, a form of weathering. The observed frequent asociation of kaolin with fluorine minerals led von Buch and Daubree to suggest that in certain instances the kaolinization, as this form of decomposition is called, might be due to exhalations of fluorhydric acid. J. H. Collins showed by experiment the possibility of such an origin, and was led to think, in the case of veins and bands sometimes extending far below the drainage level, no other conclusion was tenable. 1 Dr. Heinrich Ries, in a paper read before the American Ceramic Society in 1900, gave it as his opinion that the kaolins of Cornwall (England) and possibly those of Zettlitz in Bohemia were of deep-seated origin and due to fluoric exhalations, as noted above. Recently H. Rosier has come forward with an apparently exhaustive paper in which he advocates this origin for all kaolins. 2 Inasmuch, however, as many American kaolins do not occur in veins, but so far as observed are merely superficial phases of granitic decomposition, so far-reaching a conclusion cannot at present be accepted unqualifiedly. The fact that a large portion of American kaolin deposits occur, so far as known, in regions south of the glacial limit seems to substantiate the prevailing opinion that such are due to long-continued secu- lar decay of rock masses through the action of heat and cold, mois- ture and the carbonic acid of rainfalls, in short are due to weathering processes, as are many of the common clays. It has been repeatedly 1 Mineralogical Magazine, VII, 1886-87, P- 2I 7- 2 Neues Jahrb. fur Min. Geol. u. Pal. XV Beilage-Band, 2. Heft, 1902. ,.' 220 THE NON-METALLIC MINERALS. shown that rocks of any type containing aluminous silicates will on prolonged decomposition from atmospheric influences break down into clayey soils and clays, the nature of which is dependent to a considerable extent upon the character of the parent rock. Such are the residual clays of limestone regions, and of limestone caves, and perhaps also the so-called Indianaite of Lawrence County, Indiana. 1 The assorting and transporting power of running waters rarely allows beds of kaolin or other residual clays to remain in a condition of virgin purity or even in the place of their origin. The minute size and the shape of the constituent particles are such as to render them easy of transportation by rains and running streams to be redeposited in regularly stratified and laminated beds when the streams lose their carrying power by flowing into lakes and seas. It is through such agencies that have been formed the bedded Leda and Champlain clays of the glacial period, the Cretaceous clays of New Jersey and the fire clays of the Coal Measures, though their original constituents may have been of purely chemical or of mechanical origin. The glacial clays of Wisconsin have been described by Cham- berlain as owing their origin mainly to the mechanical grinding of glacial ice upon strata of limestone, sandstone, and shale, resulting in a comminuted product that now contains from 25 to 50 per cent of carbonates of lime and magnesia. This product of glacial grind- ing was separated from the mixed stony clays produced by the same action by water either immediately upon its formation or in the lacustrine epoch closely following. The process of separation must have been rapid and comparatively free from the agency of carbonated waters, otherwise the lime and magnesia would have been leached out. The formation of beds of clay has been confined to no par- ticular period of the earth's history, but has evidently gone on ever since the first rocks were formed and when rock decomposition began. The older beds are as a rule greatly indurated and otherwise altered, and in many instances no longer recognizable as clays at all. 1 See Rocks, Rockweathering, and Soils, pp. 172-285. SILICATES. 221 Throughput the Appalachian region clay beds of Cambrian and Silurian ages have, by the squeezing and sheering incident to the elevation of this mountain system, become converted into argillites and roofing slates. Mineral and chemical composition. Formed thus in a variety of ways, and consisting not infrequently of materials brought from diverse sources, it is easy to comprehend that the substances ordi- narily grouped under the name of clays may vary widely in both mineral and chemical composition. It may be said at the outset that the statement so frequently made to the effect that kaolinite or even kaolin is the basis of all clays is not yet well substantiated. Kaolinite is in itself not properly a clay, nor is it plastic. Further, in many cases it is present only in nonessential quantities. More open to criticism yet, because more concise, is the statement some- times made that clay is a hydrated silicate of alumina having the formula Al 2 O 3 ,2SiO 2 + 2H 2 O. It is doubtful if a clay was ever found which could be reduced to such a formula excepting by a liberal exercise of the imagination. There is scarcely one of the sili- cate minerals that will not when sufficiently finely comminuted yield a substance possessing those peculiar physical properties of unctuous feel, plasticity, color, and odor which are the only constant charac- teristics of the multitudinous and heterogeneous compounds known as clay.8. 1 Daubree, as long ago as 1878, 2 pointed out the fact that by the mechanical trituration of feldspars in a revolving cylinder with water, an impalpable mud was obtained, which remained many days in suspension, and on drying formed masses so hard as to be broken only with a hammer, resembling the argillites of the Coal Measures. The kaolins, when examined under the microscope, are found to consist largely of extremely minute colorless shreds of material which may be kaolinite; intermixed with this are fragments of 1 Referring to the odor of clay when a shower of rain first begins to wet a dry, clayey soil, Mr. C. Tomlinson has remarked that it is commonly attributed to alumina, and yet pure alumina gives off no odor when breathed upon or wetted. The fact is, the peculiar odor referred to belongs only to impure clays, and chiefly to those that contain oxide of iron. (Proceedings of the Geological Association, I, p. 242; quoted in Woodward's Geology of England and Wales, p. 439.) 2 Geologic Experimental, 1879, p. 251. 222 THE NON-METALLIC MINERALS. undecomposed feldspars and particles of quartz and other refrac- tory minerals as tourmaline, iron ores, mica, etc., that were con- stituents of the parent rock and have escaped decomposition. The ordinary residual clays have a more indefinite composition, as a rule are more or less ferruginous and contain sand particles, grains of magnetite, titanic iron, garnet, rutiles or any of the less destructible minerals. The drift or transported clays are like indefinite aggregates. The ordinary glacial Champlain or Leda clay is a quite hetero- geneous and variable compound. Prof. W. O. Crosby has shown that the blue-gray brick clays of Cambridge, 'Massachusetts, contain but from one-fourth to one-third their bulk of what he designates "true clay," the remainder being finely comminuted material of various kinds which he calls rock flour. The brick clays at Lewis- ton and vicinity contain, as shown by the microscope, a compara- tively small amount of material that can be designated kaolin, but carry particles of free quartz, scales of mica, bits *of still undecom- posed feldspar and other silicate minerals, and more rarely tourma- line, etc. Many of these clays are highly calcareous, also indeed both lime and magnesia are common constituents of any but the residual clays, occurring as a rule in the form of carbonate. The alkalies potash and soda are also common constituents though occurring commonly as silicates in the undecomposed residual material. Iron in some of its forms, as hydrated oxide, carbonate or sulphide, is an almost universal constituent, in some proportions, of clays of all kinds. The above remarks will explain why a purely chemical analysis of a clay may be of little value for the purpose of ascertaining its suitability for any particular purpose. It is essential that we know not merely the presence or absence of certain elements but also how these elements are combined. Further than this few clays are used in their natural condition, being first purified by washing and usually mixed with other constituents to give them body or fire- resisting properties. Kinds and classification. From a geological standpoint the clays may be divided into two general classes, as above noted, (i) residual, and (2) transported, the first class including a majority of the kaolin, halloysite, etc., and the second the ordinary brick and SILICATES. potters' clays, the loess, adobe, Leda, and the bedded alluvial deposits of the Cretaceous, Carboniferous, and other geological periods. Special names, based upon such properties as render them peculiarly adapted to economic purposes, are common. We thus have (i) the kaolin and China clay, (2) potters' clay, (3) pipe clay, (4) fire clay, (5) brick tile, and terra cotta clays, etc., (6) slip clays, (7) adobe, and (&) fullers' earth. These will be discussed in the order given, though they must necessarily be discussed but briefly, since the subject of clays alone could be made to far exceed the entire limits of the present volume. The names fat and lean clays are workmen's terms for clays relatively pure and plastic or carrying a large amount of mechanical admixtures, such as quartz sand. China clays. Under the name of kaolin, or China clay, it is customary to include a white pulverulent highly plastic material, resulting in part, as already noted, from feldspathic decomposition, and used in the manufacture of the finer grades of porcelain and china ware. The name kaolin, as applied, is due to a misconcep- tion, 'the material being supposed to be similar to that obtained by the Chinese at Kauling (Highridge), and from which was made the high grades of Chinese porcelain. According to Richthofen, 1 however, the material from which the porcelain of King-te-chin is made is not kaolin at all, as the word is now used, but a hard greenish rock which occurs intercalated between beds of clay slate. He says: " This rock is reduced, by stamping, to a white powder, of which the finest portion is ingeniously and repeatedly separated. This is then molded into small bricks. The Chinese distinguish chiefly two kinds of this mineral. Either of them is sold in King-te-chin in the shape of bricks, and as either is a white earth, they offer no visible differences. They are made at different places, in the manner described, by pounding hard rock, but the aspect of the rock is nearly alike in both cases. For one of these two kinds of material, the place Kaoling ('high ridge') was in ancient times in high repute ; and though it has lost its prestige since centuries, the Chinese still designate by the name 'Kao-ling' the kind of earth 1 American Journal of Science, 1871, p. 180. 224 THE NON-METALLIC MINERALS. which was formerly derived from there, but is now prepared in other places. The application of the name by Berzelius to porcelain earth was made on the erroneous supposition that the white earth which he received from a member of one of the embassies (I think, Lord Amherst) occurred naturally in this state. The second kind of material bears the name Pe-tun-tse ('white clay')." The following analysis will serve to show the average compo- sition of (i) the natural material from King- te- Chin, such as is used in the manufacture of the finest porcelain; (II) that from the same locality used in the so-called blue Canton ware; (III) that of the English Cornish or Cornwall stone; (IV) washed kaolin from St. Yrieux, France, and (V) washed kaolin from Hockessin, Dela- ware. Constituents. I. II. III. IV. V. Silica 72. cr 7-1. CC 73. C7 48 68 d.8 73 Alumina 21 OO /OOj 18 08 16-31 1 6 <17 o u -y^ O/ <(J ^ .70 Lime . . . 2 c C I ^8 I 17 16 Magnesia ,jr I 08 21 C2 Potash .46 ) o- 4 ( 41 Soda 2.OQ f 5-84 58 J -4* 1 QA Combined water 2.62 1.96 2-45 W3 12.83 Total . . 00 62 OO 7O oo 08 oo 87 IOO OO Plate XVII, Figs, i and 2, will serve to show the shape and kind of the particles in the mineral kaplinite and in a prepared sample of the Hockessin kaolin, as seen under the microscope. The name halloysite is given to a white or yellowish material closely simulating kaolin in composition, but occurring in indurated masses, with a greasy feel and luster, and which adheres strongly to the tongue, a property due to its capacity for absorbing moisture. 2 Analyses I and II by J. E. Whitfield, Bulletin 27, U. S. Geological Survey; III from Langenbeck's Chemistry of Pottery; IV from Zirkel's Lehrbuch der Petro- graphie, III, p. 758, and V by George Steiger, U. S. Geological Survey. 2 This property is characteristic of nearly all clay compounds when they are dry. It is to this same property that many of the so-called ' ' madstones " owe their imagi- nary virtues. "Nearly all the stones of this type examined by the writer have proved to be of indurated clay, halloysite, or a closely related compound. When applied to a fresh wound, such adhere until they become saturated with moisture, when they fall away. Their curative powers are of course wholly imaginary. FIG. 2. PLATE XVII. Microsections showing Appearance of (i) Kaolinite and (2) Washed Kaolin. [U. S. National Museum.] SILICATES. 225 As it is utilized for much the same purpose as is kaolin, it is included here. Halloysite is described by Gibson l as occurring in a bed some 3 feet in thickness, lying near the base of the Lower Siliceous (L. Carboniferous) formation, a little above or close to the Black Shale (Devonian), in Murphrees Valley, Alabama. This bed has been worked with satisfactory results near Valley Head, in Dekalb County. The present writer has found the material in compara- tively small quantities, associated with kaolin, in narrow veins in the decomposing gneissic rock near Stone Mountain, Georgia. A similar occurrence is described near Elgin, Scotland. Near Tuffer, Styria, halloysite is described 2 as occurring in extensive thick and veinlike agglomerations in porphyry. It is quite pure, and in the form of irregular nodules of various sizes, frequently with a pellucid, steatitelike central nucleus, passing outwardly into a pure white substance, greasy to the touch, in which are occasionally included minute pellucid granules. Outside it passes into an earthy, friable substance. The following analyses show the varying composition of halloysite from (I) Elgin, Scotland, (II) Steinbruck, Styria, and (III) Detroit Mine, Mono Lake, California: Constituents. I. II. III. Silica JQ 2Q 4.O.7 42.01 Alumina 38.S2 38.40 38.4 Limp . O Jf o 60 06 JVIagnesia o 83 I. CQ I> 5 Ferric oxide 1.42 Trace. Water. 10 34 18 oo 18 oo 99.20 A white chalky halloysite from the pits of the Frio Kaolin Mining Company in Edwards County, Texas, has the composition given below as shown by analyses made in the laboratory of the depart- ment of Geology in the National Museum: 1 Geological Survey of Alabama. Report on Murphrees Valley, 1893, p. 121. 8 Mineralogical Magazine, II, 1878, p. 264. "6 THE NON-METALLIC MINERALS. Silica 45 . 82 Alumina 39-77 Potash. 30 Ignition 13 .38 99.27 The material is somewhat variable, corresponding in part to the halloysite described by Dana, and being non-plastic, and in part being plastic to an extraordinary degree. The plastic portions are almost as gritless as starch paste. Its appearance under the microscope is shown in Plate XVIII, Fig. i, the interspaces of. the visible angular particles being occupied by the pasty, almost amor- phous material. The particles themselves act very faintly on polar- ized light, and it is not possible to determine their mineralogicaj nature. The name Indianaite has been given by Cox to a variety of halloysite found in Lawrence County, Indiana, and which he re- garded as resulting from the decomposition of Archimedes (Lower Carboniferous) limestone. It is represented as forming a stratum from 6 to 10 feet thick, underlying a massive bed of Coal Measure conglomerate 100 feet thick and overlying a bed of limonite 2 to 5 feet thick. The material like kaolin is used in the manufacture of porcelain ware. The composition of this material as given by Dana is as follows: Silica 39 per cent, alumina 36 per cent, water 23.50 per cent, lime and magnesia 0.63 per cent, alkalies 0.54 per cent, 99.67 per cent. The potters' and pipe clays belong mainly to what are known geologically as bedded clays, and are as a rule very siliceous com- pounds, carrying in some instances as much as 50 per cent of free quartz and 6 to 10 per cent of iron oxides and other impurities. They are highly plastic and of a white to blue, gray, or brown color and burn gray, brown, or red. The tables on page 244 will show the varying composition of materials thus classed. The fire clays, so called on account of the refractory nature, differ mainly in the small percentages of lime and the alkalies they carry, and to the absence of which they owe their refractory properties. FIG. 2. PLATE XVIII. Microsections showing the Appearance of (i) Halloysite and (2) Glacial Clay; the Enlargement is the Same in Both Cases. [U. S. National Museum.] SILICATES. 227 The bedded clays of the United States reach their maximum development in strata of Cretaceous and Carboniferous ages. To the Cretaceous age belong the celebrated plastic clays of New Jersey and a very large proportion of the brick, tile, and terra- cotta clays of Delaware, 1 Maryland, and Virginia. The New Jersey beds are very extensively utilized in Middlesex County and fully de- scribed in the State Geological Reports, 2 from which the following section is taken: Feet. (1) Dark -colored clay (with beds and laminae of lignite) 50 (2) Sandy clay, with sand in alternate layers 40 (3) Stoneware clay bed 30 (4) Sand and sandy clay (with lignite near the bottom) 50 (5) South Amboy fire-clay bed 20 (6) Sandy clay (generally red or yellow) 3 (7) Sand and kaolin 10 (8) Feldspar bed v';>' : 5 (9) Micaceous sand bed 20 (10) Laminated clay and sand 30 (n) Pipe clay (top white) 10 (12) Sandy clay (including leaf bed) 5 (13) Woodbridge fire-clay bed 20 (14) Fire-sand bed 15 Raritan clay beds: (15) Fireclay 15 (16) Sandy clay 4 (17) Potters' clay 20 Total , 347 The following section from Bulletin No. 3 of the Geological Survey of Missouri will serve to show the alternating character of the Coal Measure clays at St. Louis and their varying qualities as indicated by the uses to which they are put: 3 "(i) Loess, 20 feet. "(2) Limestone (Coal Measure), 5 feet. "(3) Clay, white and yellow, used for sewer-pipe manufacture, called ' bastard fire clay,' 3 to 4 feet. 1 This of course does not include the kaolin deposits of Hockessin, Newcastle County, and similar deposits. 2 Report en Clay Deposits of Woodbridge, South Amboy, and other places in New Jersey, 1878. 8 Bulletin No. 3, Geological Survey of Missouri, 1890. THE NON-METALLIC MINERALS. "(4) Clay, yellow and red, sold for paint manufacture and for coloring plaster and mortar, called 'ochre,' 3 feet. "(5) Clay, gray to white, used for paint manufacture and filling, i foot 6 inches. "(6) Pipe clay, variegated, reddish brown and greenish, called 'keel,' 12 feet. "(7) Sandstone. 11 (8) Slaty shale. "(9) Coal. " (10) Fire clay, becoming sandy toward the base." When first mined these Coal Measure clays are usually very hard, but on exposure to the weather slake and fall into powder. They are as a rule much less fusible than are the glacial clays, and are used mainly in the manufacture of fire brick, sewer pipe, terra- cotta stoneware, as crocks, fruit jars, jugs, etc., glass and gas retorts, smelting pots, etc. Some of these articles are made direct from the natural clays, while others are from a mixture of several clays or of a clay mixed with powdered quartz and feldspar. For ordinary brick-making purposes a great variety of materials are employed; in some cases residuary deposits, and in others alluvial and sedimentary. Throughout the glacial regions of the United States a fine unctuous blue-gray material, laid down in estu- aries during the Champlain epoch, the so-called Leda clays, are the main materials used for this purpose. The bowlder clays of the glacial regions are also sometimes used when sufficiently homo- geneous. The prevailing colors of the Leda clays are blue-gray below the zone of oxidation and yellowish or brownish above. They all carry varying amounts of iron, lime, magnesia, and the alkalies, and when burned turn to red of varying tints. They fuse with comparative ease and are used, aside from brick and tile making, for the coarser forms of earthenware, as flower pots, being as a rule mixed with siliceous sand to counteract shrinkage. The mining of such material is of the simplest kind, and consists merely of scraping away the overlying soil and sand, if such there be, and removing the clay in the form of sidehill cuts or open pits. Plate XIX, facing this page, shows a cut in one of the beds at > SILICATES. 229 Lewiston, Maine. The material here is fine and homogeneous, of a blue-gray color, and contains no appreciable grit. It is mixed with siliceous sand and used for making bricks, baking red. An analysis of the material in its air-dry state yielded results as below: Silica (SiO 2 ) 56.17 Alumina (A1 2 O 3 ) 24. 25 Ferrous oxide (FeO) 3-54 Lime (CaO) 2 .09 Magnesia (MgO) 2.57 Potash (K 2 O) 4.06 Soda (Na 2 O) 2.25 Ignition (H 2 O) 4.69 99-62 The appearance of the Lewiston clay under the microscope is shown in Plate XVIII, Fig. 2. Leda clays from Beaver County, Pennsylvania, used in the manufacture of terra cotta at New Brighton, are reported l as having the following composition: Silica 46.160 67.780 Alumina, . . 26.076 l6.29O Sesquioxide of iron . . 7.214 4.^7O Titanic acid .740 .780 Lime. 2.2IO .600 Magnesia I.S2O .727 Alkalies 3.24.6 2.OOI Water 11.220 6.34O Total OQ 286 00.088 Vitrified brick for street pavements are made from fusible clays, sometimes in their natural condition and sometimes mixtures of ground shale and clay. The following analyses are given of the materials used by the Onondaga Vitrified Pressed Brick Company, of New York: 2 1 Second Geological Survey of Pennsylvania, Report of Chemical Analyses, p. 257. 2 Bulletin of the New York State Museum, III, No. 12, March, 1895. Clay Industries of New York, p. 200. 2 3 THE NON-METALLIC MINERALS. Constituents. Calcareous layer in shale bank. A green brick; being a mixture of the differ- ent shales. Red shale. Blue shale. Clay. Silica 2 ^ 4.0 CA 2 C C2 2Q r7 70 Alu'nina O 4.6 16 89 18 85 4O-OJ Peroxide o^ iron 2 24. c RT 6 cc Lime 22 8l :>.oi 47 A u -55 J 7.6 .^u Magnesia IO 3Q 521 5-O 1 "' 44.O ^/6 467 lu.yy 6 ?8 Carbonic acid 2O.O6 4 20 3O4. 7 ^2 72/1 Potash jQf 2 Q ? 46c 41 1 7 J 26 Soda **?3 ? ^^ater and organic matter 1 60 '6 501 *'S3 5^O 8 oo Oxide of manganese .v_>j. Trace Trace Total OO.Sl OQ ^Q oo 80 QO 7O oo 86 The name slip clay is given to a readily fusible, impalpably fine clay used for imparting a glaze to earthenware vessels. These clays carry iron oxides, potash, and soda, together with lime and magnesia, in such proportions that they vitrify readily, forming thus an impervious glass over those portions of the ware to which they are applied. The following analyses show (I) the composition of a slip clay used in pottery works in Akron, Ohio, and (II) one from Albany, New York: Constituents. I. II. Silica 60.40 C8.H4 Alumina IO 4.2 I ^ 4.1 Iron sesouioxide. 5-3 6 3IO Lime 0.88 6.3,0 Magnesia 4.28 7.4.0 Alkalies 0.87 4.4C Sulphuric acid o 6^ I IO Phosphoric acid o oo Carbonic acid and water 8.01; 8.08 Total IOO.OO 100.47 The Albany clay is stated by Nason 1 to glaze at comparatively low temperatures and to rarely crack or check. It occurs in a stratum 4 to 5 feet thick. It is used very extensively in the United States, and has even been shipped to Germany and France. 1 Forty-seventh Annual Report of the State Geologist of New York, 1893, p. 468. SILICATES. 231 The name adobe is given to a calcareous clay of a gray-brown or yellowish color, very fine grained and porous, which is sufficiently friable to crumble readily in the fingers, and yet has sufficient coher- ency to stand for many years in the form of vertical escarpments, without forming appreciable talus slopes. It is in common use throughout Arizona, New Mexico, and Mexico proper for building material, the dry adobe being first mixed with water, pressed in rough rectangular wooden molds some 10 by 18 or more inches and 3 or 4 inches deep, and then dried in the sun. In some cases chopped straw is mixed with it to increase its tenacity. Buildings formed of this material endure for generations and even centuries in arid climates. The material of the adobe is derived from the waste of the surrounding mountain slopes, the disintegration being mainly mechanical. According to Prof. I. C. Russell it is assorted and spread out over the valley bottoms by ephemeral streams. It con- sists of a great variety of minerals, among which quartz is con- spicuous. The chemical nature of the adobes varies widely, as would naturally be expected, and as is shown in the following analyses from Professor Russell's paper: * ANALYSES OF ADOBE. Constituents. I. Santa Fe", New Mexico. II. Fort Win- gate, New Mexico. III. Humboldt, Nevada. IV. Salt Lake City, Utah. SiO,. . 66.60 26.67 44.64 10.24 Al 6 . 14 16 O QI 1 3 10 3.26 Fee 3 , A -28 o 64 C 12 I.OO MnO O OQ Trace. O.I 3 Trace. CaO 2 -4Q 36.40 I Tf 01 38.Q4 M>O I 28 o c i 2 06 2 7? KO. . 121 Trace 1. 71 '/O Trace. Na,O. . . O.67 Trace. O.CQ Trace. CO,.. O.77 2C.84 X y 8.<^ 2Q.S7 p o O'2O O 7 C O 04. O.2 3 SO . O 4 I o 82 0.64. O.ZT. Cl. O.34 0.07 O.I4 O.II H O 4Q4. 2 26 ? 84. I 6? Organic matter 2 OO c jo 3A 1 ! l.U/ 2 QO Total OQ.72 00-07 00-70 IOO.T,< 1 Subaerial Deposits of North America, Geological Magazine, VI, 1889, pp. 289 and 342. 232 THE NON-METALLIC MINERALS. The name loess is given to certain quaternary surface deposits closely simulating adobe, but concerning the origin of which there has been considerable dispute. Deposits in the United States are, according to the best authorities, of subaqueous origin. Clays of this nature are, as a rule, higher in silica than the adobes and correspondingly poorer in alumina. Loess is a common surface deposit throughout the Mississippi Valley, and is in many instances of such consistency as to be utilized for brickmaking. The analyses given below are from Professor Russell's paper: ANALYSES OF THE LOESS OF THE MISSISSIPPI VALLEY. Constituents. No. i. No. 2. No. 3. No. 4. SiO, 72.68 64.61 74.46 60.60 Al O 12. O3 10.64 12 26 7 OC. FeO 3 3.C-? 2.61 32C 7-05 2 6l FeO. 3 6-55 O.QO O.SI O.I2 o 67 TiO,. O.72 0.40 O.I4. O 2 P 2 O O.23 0.06 O.OQ O I 2 MnO O.o6 o.os O.O2 O.I2 CaO I.C.Q C.4I 1. 60 8.06 MeO I. II 3.6o I 12 o.yu 4 CO NaO. . 1.68 l.afi I 43 y* I 17 KO. . 2.13 * 2.06 ^--IS 1.83 I 08 H."O. . O2.=;o a2.o? #2.70 (It 14, CO 0.30 6.31 O.40 0.63 scC . o.cx O.II O.o6 O.I2 C. O.OQ O.I 7 O.I2 O IQ Total IOO.2I 00-00 00.78 00. .4 a. Contains H of organic matter, dried at 100 C. Properties of days. The cause of the peculiar properties of clays, particularly those of plasticity and induration, cannot as yet be said to have been explained. Various explanations have been made with reference to plasticity, but none which have proven to be conclusive. It has been ascribed to the alumina, to the com- bined water and the shape and size of the constituent particles, but no one quality seems to cover all cases, and in the end it will probably be shown that there are many phases of plasticity due perhaps to as many causes. Cook thought to show * that some of the non-plastic clays which become plastic on kneading were 1 Report on Clay Deposits, Geological Survey of New Jersey. SILICATES. 233 composed of masses of hexagonal plates or scales piled up in long bundles, and that the kneading necessary to produce plasticity broke up the bundles leaving a homogeneous matrix of crushed material derived therefrom. Subsequent investigation has, however, failed to confirm this view. The presence of combined water has un- doubtedly some effect, since clays so highly heated as to drive off this water are no longer plastic. The alumina alone cannot be the cause, otherwise kaolin would be one of the most plastic of clays, which is far from being the case. Moreover there are other hydrous aluminum compounds which are not plastic in the least. Accord- ing to certain Russian authorities plasticity is due not only to the interlocking of clay particles but varies with the texture, the ex- tremely coarse and fine varieties being less plastic than the inter- mediate forms. This view is held also by Dr. H. Ries and H. A. Wheeler. 1 H. Rosier 2 regards plasticity as due to the flattened form of the constituents, their softness and their fineness, and there is much to support this view. So far as the compiler's own observations go, plasticity is not dependent wholly upon hydration nor size nor shape of the constit- uent particles. The glacial (Leda) clays are made up of fresh, sharply angular particles of various minerals and contain less than 5 per cent combined water; yet in their natural condition they are extremely plastic, and scarcely less so when mixed with two-fifths their bulk of ordinary siliceous sand, as is done in the process of brickmaking. The Albany County, Wyoming, clay, on the other hand, equally or even more plastic and exceedingly pasty, is made up of extremely minute particles of fairly uniform size, scarcely angular, and apparently all of the same, mineral nature throughout. This yields some 16 per cent of water, on ignition, as shown in analysis, p. 243. On the whole, the evidence seems to show that the plasticity is due to the manner in which the particles conduct themselves toward moisture, and this is apparently dependent upon the size and shape and the proportional admixture of varying sizes 1 Clay Deposits and Clay Industry in North Carolina, Bulletin No. 13, North Carolina Geological Survey, 1897. 2 Neues Jahrb. fur Min. u. Paleon., Beilage-Band, 2. Heft, Vol. XV. 234 THE NON-METALLIC MINERALS. of the constituents rather than upon their chemical composition. The colloidal nature of the constituents of certain clays may per- haps prove an important factor. The work now being done by Dr. Whitney, of the Agricultural Department, on the relationship of soils to moisture bids fair to throw important light upon this branch of the subject. The expulsion of the combined water in a clay is nearly always accompanied by a diminution in volume, which varies directly as the water, or the purity of the clay. Pure kaolin shrinks as much as one-fourth of its bulk, it is stated, sometimes even more. The sandy clays used in making sewer-pipe and stoneware shrink from the tempered state from one-ninth to one-sixteenth, usually about one-twelfth. The shrinkage of the raw clay would be very much less, probably not over 3 or 4 per cent. A clay, when all the water of crystallization is expelled, will not shrink any more at red heat, but with increased heat will shrink more and more up to the moment of fusion. A pure kaolin apparently shrinks when heated a second time, even if the water is all expelled by the first heat, yet it is practically impossible to fuse it. But a good flint clay containing some sand will lose all shrinkage on being once calcined at white heat. Such clay is then used to counteract shrinkage in a body of green clay, as this effect is obtained by mix- ing in sand or some non- shrinking body. Many clays contain sand enough naturally to shrink little or none on heating, and some are so sandy as to actually expand, though usually at the expense of soundness of structure; for the particles of clay will shrink away from the grains of sand and this renders the structure very friable. The refractory or fire-proof properties of clays seem to depend largely upon the alumina and silica, and their freedom from all constituents which are fusible in themselves or which would com- bine with others forming a flux. Pure alumina, or pure quartz alone, is practically infusible. The constituents tending to make a clay fusible are iron, soda, potash, lime, and magnesia. Which of these is the more detrimental it would be difficult to say. Iron is not so powerful a flux as either potash or soda; but on the other hand it is much more abundant, and may moreover impart an unsatisfactory color. SILICATES. 235 The effect of the iron is detrimental to the appearance of clay ware, and consequently has a direct bearing on the price of goods, while potash shows no more on the surface than on the inside, and when present in the usual small amounts it produces an incipient vitrification which makes the ware ring like a bell when struck, and is often a help in selling. The extent to which iron may be present without detriment is a point on which authorities do not agree. The Stourbridge clay of England, a very refractory clay, has 2.25 per cent of iron on an average of 100 analyses, with extremes of 1.43 and 3.63. Gros Almerode clay has 2.12; Coblentz, 2.03; New Castle, 2.32, and yet all these clays are famous. Test mixtures of iron and pure kaolin have been run higher than this and have stood well, but as a general rule it is unsafe to rely for fine qualities on a clay with over 2 per cent of iron, particularly if the other impurities are de- veloped in any amount. It is a well-known principle in chemistry that mixtures of bases are much more active fluxes than an equal amount of any one base ; so with iron, its effect shows worse when in presence of other fluxing agents. The condition of the iron, whether as a sesquioxide or protoxide is also an important matter, the latter form only, it is stated, being likely to combine with the silica. Sulphide of iron has a bad effect on the clay since its decom- position gives rise to the lower oxide of iron, besides the effect which the sulphur may have. A silicate of iron is also detrimental, since it melts at a comparatively low temperature. On a piece of ware, iron in the uncombined state imparts a buff or red color; when combination begins and progresses the ware is of a bluish-gray cast, deepening as the fusion of the iron proceeds, and running to glassy black if much iron is present. Lime and magnesia act as fluxes, but in any but the glacial clays the comparatively small amounts present causes them to be but little thought of as detrimental. They are probably present as silicates, and as these are fusible their action is evidently unfavor- able. When these bases are present as carbonates they combine at a higher temperature than iron or potash. The Milwaukee brick clays, as already noted, are full of carbonates of lime and 236 THE NON-METALLIC MINERALS. magnesia, and require a very hot burn, but when once the lime and silica combine they destroy the effect of 5 per cent of iron, and im- part a cream color. A brick of this kind presents an even, fine- grained, vitrified appearance on its fracture. 1 The amount of potash which a clay can contain and keep its fire properties is variously put by different authorities. As with iron, pure kaolin will stand a good deal when no other base is present, but a multiplicity of bases makes fusion easy. Titanic acid is regarded as neutral to fire qualities, being itself practically infusible. Testing clays. The statement of the tendencies and compara- tive power of the dangerous impurities of clay would lead one to believe that predictions as to their result in a given clay could be made with some confidence, but the best practice does not yet trust to analysis alone. The most complete test of a clay now known would be obtained by use of analysis, coupled with a fire test made especially to develop such points as the analysis indicates to be weak ones. Fire tests are of two kinds one consists in subjecting the clay to absolute heat without the action of any accompaniments, and the other in putting the clay through the course of treatment 1 They (lime and magnesia) have also the remarkable property of uniting with the iron ingredient to form a light-colored alumina-lime-magnesia-iron silicate, and thus the product is cream-colored instead of red. Mr. Sweet has shown by analysis that the Milwaukee light-colored brick contain even more iron than the Madison red brick. At numerous points in the Lake region and in the Fox River valley cream- colored brick are made from red clays. In nearly or quite all cases, whatever the original color of the clay, the brick are reddish when partially burned. The explana- tion seems to be that at a comparatively moderate temperature the iron constituent is deprived of its water and fully oxidized, and is therefore red, while it is only at a relatively high heat that the union with the lime and magnesia takes place, giving rise to the light color. The calcareous and magnesian clays are, therefore, a valuable substitute for true aluminous clays, for they not only bind the mass together more firmly, but give a color which is very generally admired. They have also this practical advantage, that the effects of inadequate burning are made evident in the imperfect development of the cream color, and hence a more carefully burned product is usually secured. It is possible to make a light-colored brick from a clay which usually burns red by adding lime. The amount of lime and magnesia in the Milwaukee brick is about 25 per cent. In the original clays in the form of carbonates they make up about 40 per cent. (Geology of Wisconsin, I, 1873-79, p. 669.) SILICATES. 237 for which it is designed to be used. The former develops the absolute quality of the clay as good or bad, the latter proves or disproves the fitness of the clay for the work. The latter is better of course as a business test wherever it is practicable to use it. The former can be made only in a specially adapted furnace. The clay in this test is cut into one-inch cubes with square edges, and is set in a covered crucible resting on a lump of clay of its own kind, so that it touches no foreign object. The heat is then applied, and its effect will vary from fusing the mass to a button to leaving it with edges sharp and not even glazed on the surface. Experience soon renders one proficient in judging of clays by this test. 1 A method of testing the fusibility of clays by comparing them with samples of known composition and fusibility has of late years come into extensive use. These prepared samples, known from their inventor and their shape as Seger's pyramids, consist of mix- tures in varying proportions of kaolin and certain fluxes, so pre- pared that there is a constant difference between their fusing points. When such pyramids, together with, the samples .to be tested, are placed in a furnace or kiln, they begin to soften as the temperature is raised, and as it approaches their fusion point the cones bend over until the tip is as low as the base. When this occurs the temperature at which they fuse is considered to be reached. 2 Uses. Clay when moistened with water is plastic and suf- ficiently firm to be fashioned into any form desired. It can be shaped by the hands alone; by the hands applied to the clay as it turns with the potter's wheel, or it can be shaped by moulds, presses, or tools. When shaped and dried, and then burned in an oven or kiln, it becomes firm and solid, like stone; water will not soften it, it has entirely lost its plastic property, and is per- manently fixed in its new forms, and for its designed uses. These singular and interesting properties are possessed by clay alone, and it is to these it owes its chief uses. It is used (i) for making 1 Geological Survey of Ohio, Economic Geology, V, pp. 652-655. See Dr. Ries's paper 'on North Carolina clays, already quoted, and also his numerous contributions on their subject in the volumes of the United States Geolog- ical Survey relating to mineral statistics. 238 THE NON-METALLIC MINERALS. pottery; (2) for making refractory materials; (3) for making build- ing materials; (4) for miscellaneous purposes. Pottery. Pure clay worked into shapes and burned, consti- tutes earthenware. The ware of itself is porous, and will allow water and soluble substances to soak through it. To make it hold liquids, the shaped clay before burning is covered with some sub- stance that in the burning of the ware will melt and form a glass coating or glazing which will protect the ware in its after uses from absorbing liquids, and give it a clean smooth surface. The color of the ware depends on the purity of the clay. Clays containing oxide of iron burn red, the depth of color depending on the amount of the oxide, even a small fraction of i per cent being sufficient to give the clay a buff color. Clay containing oxide of iron in sufficient quantity to make it partially fusible in the heat required to burn it, when made into forms and burned, is called stoneware clay. The heat is carried far enough to fuse the particles together so that the ware is solid and will not allow water to soak through it; and the fusion has not been carried so far as to alter the shapes of the articles burned. The oxide of iron by the fusion has been combined with the clay, and instead of its characteristic red, has given to the ware a bluish or grayish color. Stoneware may be glazed like earthenware, or by putting salt in the kiln, when its vapor comes in contact with the heated ware and makes with it a sufficient glaze. Clay which is pure white in color and entirely free from oxide of iron, may be intimately mixed with ground feldspar or other min- erals which contain potash enough to make them fusible, and the mixture still be plastic so as to be worked into forms for ware. When burned, such a composition retains its pure white color, while it undergoes fusion sufficient to make a body that will not absorb water. And its surface can be made smooth and clean by a suitable plain or ornamented glaze. Ware of this kind is porcelain or china. The analyses on page 244, compiled from works believed to be authoritative, show the varying character, so far as chemical com- position is concerned, of the clays. In most of the analyses, it will be observed, the silica existing in the form of quartz is given in a separate column from the combined, while in column 4 is given SILICATES. 239 the actual calculated percentage of kaolin which the analyses in- dicate each sample to contain. Refractory materials. Modern improvements in metallurgy, and in furnaces for all purposes, are dependent to a great degree on having materials for construction which will stand intense heat without fusing, cracking, or yielding in any way. The two materials to which resort is had in almost all cases are pure aluminous clay, and quartz in the form of sand or rock. .They are both infusible at the highest furnace heats. The clay, however, is liable to have in it small quantities of impurities which are fusible, and it shrinks very much when heated to a high -temperature. Quartz rocks are very liable to crack to pieces if heated too rapidly, and both the rocks and sand are rapidly melted when in contact with alkalies, earths, or metallic oxides, at a high temperature. They do not shrink in heating. Sandstone, or quartz rock, is not as much used as a refractory material as it was formerly. Bricks to resist intense heat are made of clay, of sand, and of a mixture of clay and sand. The different kinds are specially adapted to different uses. fire bricks of clay, or clay and sand, are the ones which have been generally made in the United States. To make these, the clay which stands an intense heat the best is selected as the plastic material of the brick. This is tempered so that it may not shrink too much or unevenly in burning, by adding to the raw clay a portion of clay which has been burned till it has ceased to shrink and then ground, or a portion of coarse sand, or a quantity of so- called feldspar. These materials are added in the proportions which the experience of the manufacture has found best. The formula for the mixture is the special property of each manufacturer, and is not made public. The materials, being mixed together and properly wet, are molded in the same way as common bricks, and after they have dried a little they are put into a metallic mold and subjected to powerful pressure. They are then taken out, dried, and burned in a kiln at an intense heat. It does not appear which is the best for tempering, burned and ground clay, or coarse sand, or feldspar. Reputable manufacturers are found who use each of these materials, and make brick that stand fire well. It is of the utmost importance to select the materials 240 THE NON-METALLIC MINERALS. carefully, and to allow no impurity to get in while handling the clay or working the components together. Fire bricks intended, in addition to their refractory qualities, to retain their size and form under intense heat without shrinkage, have been made to some extent. The English Dinas bricks are of this kind, and the German and French "silica bricks." The Dinas bricks are of quartz sand or crushed rock, and contain very little alumina and about i per cent of lime. They stand fire re- markably well, the lime being just enough to make the grains of sand stick together when the bricks are intensely heated. In the other "silica bricks," fire clay to the amount of 5 or 10 per cent is mixed with the sand, and this plastic material makes the particles of the sand cohere sufficiently to allow of handling the bricks before burning. They have met the expectation of those who made them, and are extensively used. 1 Paper clay. Clay which is pure white and that also which is discolored and has been washed to bring it to a uniform shade of color, is used by the manufacturers of paper hangings, to give the smooth satin surface to the finished paper. It is used by mixing it up with a thin size, applying it to the surface of the paper, and then polishing by means of brushes driven by machinery. The finest and most uniformly colored clays only are applicable to this use, and they are. selected with great care. Clay is also used to some extent by paper manufacturers, to give body and weight to paper. Heavy wrapping paper, such as is used by the United States Post-office Department, must, according to specifications, contain 95 per cent of jute butts and 5 per cent of clay. The cheaper forms of confectionery, particularly such as is sold from carts upon the streets, is very heavily adulterated with this material. Alum clay. A large quantity of clay is sold every year to the manufacturers of chemicals, for making alum. A rich clay is needed for this purpose. Alum is made by digesting the clay in sulphuric acid, which forms sulphate of alumina, then dissolving out the latter salt from the silica and other impurities, and forming 1 Geological Survey of New Jersey, Report on Clay Deposits, pp. 307-312. SILICATES. 241 it into alum by the addition of the necessary salt of potash, soda or ammonia, and crystallizing out the alum. The white clay of Gay Head and Chilmark, Martha's Vineyard, Massachusetts, was at one time used extensively for alum-making, according to Edward Hitchcock. 1 As a substitute for sand in making mortar and concrete clay is perhaps the best material to be found. For this purpose the clay is burnt so that it is produced in small irregular pieces that are very hard and durable. These pieces are then ground to a fairly fine powder, which is used to mix with the lime or cement just as sand would be. The result is a very strong mortar, in some cases stronger than when sand is employed. 2 The so-called gumbo clays, sticky, tough, and dark-colored clays of the Chariton River region, Missouri, are hard burned and used for railroad ballast and macadam. Under the names of Rock Soap and Mineral Soap there have from time to time been described varieties of clay which, owing to their soapy feeling, are suggestive of soap, and which in a few instances have been actually used in the preparation of this material. A rock soap from Ventura County, California, has been described by Prof. G. H. Koenig as a mixture of sandy and clayey or soapy material in the proportion of 45 per cent of the first and 55 per cent of the second. The chemical composition of the material and of the two portions is given below: Constituents. Crude material. Sandy portion. Soapy portion Silica 67-55 12.97 0.77 0.85 i-43 I 3-63) 13-67 69.40 I 3-5 0.30 Trace 4-55 12.25 73 I0 14 10 ] Not de h ter- mined. 6.70 Alumina and iron Lime ^Magnesia Potash Soda Water Nearly all the silica is reported as being in a soluble or opalescent state and the alumina as either a hydrate or very basic silicate. It 1 American Journal of Science, XXII, 1832, p. 37 2 The World's Progress, February, 1893. THE NON-METALLIC MINERALS. is" said 1 that at one time the material was made into a variety of useful articles, as "salt water soap," scrubbing and toilet soap, tooth powder, etc. A somewhat similar material from Elk County, Nevada, has been used for like purposes, and put upon the market under the name of San-too-gah-choi mineral soap. This clay is of a drab color, with a slight pinkish tint, a pronounced soapy feeling and slight alkaline reaction when moistened and placed upon test paper. An analysis by R. L. Packard in the laboratory of the U. S. National Museum yielded: Silica 48 . 80 Alumina J 8-57 Iron oxides 3 .88 Lime i .07 Magnesia 2.52 Soda 2.32 Potash 1. 12 Ignition 21.13 Total. 99-41 Mention may be made here also of the material sold in the shops under the name of Bon Ami and used for cleansing glass and other like substances. This under the microscopeshows abundant mi- nute sharply angular particles, consisting of partially decomposed feldspar mixed with a completely amorphous mineral which may be opalescent silica or possibly a very finely comminuted pumice. An analysis by R. L. Packard yielded: Silica 59-86 Alumina 18 . 74 Magnesia o - 34 Potash 10 . 70 Soda 3.51 Ignition 7 .67 Total 100.82 Alcohol extracts 7.43 per cent, and water 0.244 per cent in addi- tion, the extract having a soapy appearance and the odor of some essential oil. 1 Sixth Annual Report of the State Mineralogist of California, 1886, Pt. i, p. 132. SILICATES. 243 A peculiar soapy clay found in Albany, Crook, Weston, and Natrona Counties, Wyoming, has been shipped in considerable quantities during the past few years to Philadelphia, New York, and Chicago, where it was sold under the name of Bentonite at prices varying from $5.00 to $25.00 per ton. It is stated l to have been used in paper manufacture, as a packing for horses' feet; for a time as a soap in one of the local railway hotels, and in the mak- ing of "phlogiston," a substance widely used in the West in the form of a plaster applied to the chest in cases of pneumonia or croup. It has been suggested as admirably suited for use as a "retarder" for the hard-finish plasters now coming into use for walls. This clay is regarded by T. B. Read as originating through the decomposition of the feldspar labradorite occurring in the anor- thosite of the Laramie Mountains. The chief physical charac- teristic of this clay, aside from its soapy feeling, is its enormous absorptive power, the absorption being attended naturally with an increase in bulk amounting to several times that of the original mass. 2 Plate XX, Fig. i, shows the extreme fineness and homoge- neity of this clay as seen under the microscope. The reported analyses are as follows: Constituents. I. Rock Creek. II. Crook County. III. Weston County. IV. Natrona County. SiO 2 . CQ 78 6 1. 08 67. 2 6c.24 ALO,. , I ?.IO 17.12 v a**3 12. 02 it;. 88 Fe 2 0, 2.40 7.17 7.7O 7.12 MgO.. 4.14 1.82 7.7O C.74 CaO 0.73 2.6o 4-12 C.74 Na O K O (a} bo 20 (a) SO . (a) 088 I 00v loOvt- 0> 0, '(O'H) J ^ . ^Svo ; ^^^SS M M M *( S O Z IV) OMIOVI OOM IOMW^O Buiumty ScT^S ? * ^ScT^^ (SQIS) B0 -tjtg psuiqtuoQ H CMOOto OOv lO'frOOOlO |i|^ i liJii^rii; Name of Company and Locati tf'.ai 1 . iWl-LfHl'lJ I |||:|j 1 I Si!: 1 2.1??- if G WQ-O :ffi*g | ^ | :| : >^ .g| :g : 3 Pt||"5 1 ^ "P-l i^l.Nil! afgjgl g !:"!: ^||1 J8 W Woo O CQ^ H^I^WKOQ SILICATES. ^ to 10 O to NO to O 0\ ON ON O ON ON 0> M ON to t^ d 06 O ON O O to O "O to O 8 8 88 * O "t Ot oo tooo 10 ON O ON O> ON ON 0> o' H | Ov N NO oo d d Ov ' vO . to o ! o ON ON . ON d d N <* M * e> Ov NO _ to -0 ^J o to Ov o to ^ ; N to Ov . CN! ' 4 N ON CONO tO N ON '. do ^ i ! : o* d to ' Ov to d 8 S ! o H ' * : NO O OV H H CO M t- do' 4 ON d M oo (J *>. 7 H . bO 10 o O N O> 10 00 O $ c d S^ ?o * o : J O ^O \O V * . . Tf t^ H 00 00 NO O t VO NO 10 O t*. CO . CN,' NO U M O to H * >> >. >. i 1 ? l o o ON ' OO '. H ! 00 O oo CO . CO 10 N Pipe Clay. N. U. Walker, Walker's Station, Ohio (sewer pipe).t W. H. Evans, Waynesburg, Ohio (drain pipe).t A. O. Jones, Columbus, Ohio (drain tile).f Whitmore, Robinson & Co., Akron, Ohio (kaolite slip clay).t Fire Clay. C. E. Holden, Mineral Point, Ohio.t Scioto Fire Brick Co., Sciotoville, Ohio.t Do.t Wassail Fire Clay Co., Columbus, Ohio.t Island Fire Clay Co., near Steu- benville, Ohio.t Etna Fire Brick Co., Oakhill, Ohio.t Brick Clay. Milwaukee brick clay, Wisconsin.t. . Mount Savage, Maryland.* Newcastle, England. t Sayre & Fisher, front brick clay, Sayreville New Jersey.* 41 246 THE NON-METALLIC MINERALS. The bibliography of clays is very extensive, and but a few refer- ences are given here. The reader is referred particularly to Branner's Bibliography of Clays and the Ceramic Arts, 1 and to the papers of Dr. H. Ries in the reports on the Mineral Resources of the United States, published annually by the U. S. Geological Survey. S. W. JOHNSON, JOHN M. BLAKE. On Kaolinite and Pholerite. American Journal of Science, XLIII, 1867, p. 351. J. C. SMOCK. The Fire Clays and associated Plastic Clays, Kaolins, Feldspars, and Fire Sands of New Jersey. Transactions of the American Institute of Mining Engineers, VI, 1877, p. 177. GEORGE H. COOK. Report on the Clay Deposits of Woodbridge, South Amboy, and other places in New Jersey. Geological Survey of New Jersey, 1878. RICHARD C. HILLS. Kaolinite, from Red Mountain, Colorado. American Journal of Science, XXVII, 1884, p. 472. See also Bulletin No. 20, U. S. Geological Survey, 1885, p. 97. J. P. LESLEY. Some general considerations respecting the origin and distribution of the Delaware and Chester kaolin deposits. Annual Report Geological Survey of Pennsylvania, 1885, p. 571. J. H. COLLINS. On the Nature and Origin of Clays: The Composition of Kaolinite. Mineralogical Magazine, VII, December, 1887, p. 205. American Journal of Science, XLII, 1892, p. n. EDWARD ORTON. The Clays of Ohio, Their Origin, Composition, and Varieties. Report of the Geological Survey of Ohio, VII, 1893, pp. 45-68. EDWARD ORTON, JR. The Clay Working Industries of Ohio. Report of the Geological Survey of Ohio, VII, 1893, pp. 69-254. H. O. HOFMAN, C. D. DEMOND. Some experiments for Determining the Refractori- ness of Fire Clays. Transactions of the American Institute of Mining Engineers, XXIV, 1894, p. 42. W. MAYNARD HUTCHINGS. Notes on the Composition of Clays, Slates, etc., and on some Points in their Contact-Metamorphism. The Geological Magazine, I, 1894, p. 36. H. JOCHUM. The Relation between Composition and Refractory Characters in Fire Clays. Minutes of Proceedings of the Institution of Civil Engineers, CXX, 1894-95, P- 43 1 - J. A. HOLMES. Notes on the Kaolin and Clay Deposits of North Carolina. Transactions of the American Institute of Mining Engineers, XXV, 1895, p. 929. HEINRICH RIES. Clay Industries of New York. Bulletin No. 12 of the New York State Museum, III, March, 1895, pp. 100-262. JOHN CASPER BRANNER. Bibliography of Clays and the Ceramic Arts. Bul.letin No. 143, U. S. Geological Survey, 1896. 1 Bulletin No. 143, U. S. Geological Survey, 1896. SILICATES. 247 W S. BLATCHLEY. A Preliminary Report on the Clays and Clay Industries of the Coal and Coal-Bearing Counties of Indiana. The School of Mines Quarterly, XVIII, 1896, p. 65. W. MAYNARD HUTCHINGS. Clays, Shales, and Slates, i The Geological Magazine, III, 1896, p. 309. CHAS. F. MABERY, OTIS T. FLOOZ. Composition of American Kaolins. Journal of the American Chemical Society, XVIII, 1896, p. 909. CHAS. F. MABERY, OTIS T. FLOOZ. Clay, Bricks, Pottery, etc. Thirteenth Report of the California State Mineralogist, 1896, p. 612. THOMAS C. HOPKINS. Clays and Clay Industries of Pennsylvania. Appendix to the Annual Report of the Pennsylvania State College for 1897. J. NELSON NEVIUS. Kaolin in Vermont. Engineering and Mining Journal, LXIV, 1897, p. 189. HEINRICH RIES. The Clays and Clay-Working Industry of Colorado. Transactions of the American Institute of Mining Engineers, XXVII, 1897, P- 336- H. A. WHEELER. Clay Deposits. Missouri Geological Survey, XI. W. W. CLENDENNIN. Clays of Louisiana. Engineering and Mining Journal, LXVI, 1898, p. 456. M. H. CRUMP. The Clays and Building Stones of Kentucky. Engineering and Mining Journal, LXVI, 1898, p. 190. W. C. KNIGHT. Bentonite. [A New Clay.] Engineering and Mining Journal, LXVI, 1898, p. 491. The Building Stones and Clays of Wyoming. Engineering and Mining Journal, LXVI, 1898, p. 546. HEINRICH RIES. Physical Tests of New York Shales. School of Mines Quarterly, XIX, 1898, p. 192. The Ultimate and the Rational Analysis of Clays and Their Relative Advantages. Transactions of the American Institute of Mining Engineers, XXVIII, 1898, p. 160. EUGENE A. SMITH. The Clay Resources of Alabama and the Industries Dependent upon Them. Engineering and Mining Journal, LXVI, 1898, p. 369. J. E. TODD. The Clay and Stone Resources of South Dakota. Engineering and Mining Journal, LXVI, 1898, p. 371. G. E. LADD. Preliminary Reports on Clays of Georgia. Bulletin No. 6A, Geological Survey of Georgia, 1898. HEINRICH RIES. Preliminary Reports on Clays of Alabama. Bulletin No. 6, Geological Survey of Alabama, 1900. Clays and Shales of Michigan. Vol. VIII, Part I, Geological Survey of Michigan, 1900. Clays of New York. Bulletin No. 35, Vol. VII, New York State Museum, 1900. E. B. BUCKLEY. The Clays and Clay Industries of Wisconsin. Bulletin No. 8, Wisconsin Geological and Natural History Survey, 1901. L. DE LAUNAY. Observations sur les Kaolins de Saint Yrieux. Annales des Mines, Vol. Ill, Part I, 1903, p. 105. 248 THE NON-METALLIC MINERALS. 1 6. FULLERS' EARTH. The name fullers' earth is made to include a variety of clay-like materials of a prevailing greenish- white or gray, olive or olive-green or brownish color, soft, and with a greasy feel. When placed in water such fall into powder, imparting a slight murkiness to the liquid, but do not become plastic as do the ordinary clays. For a long time the principal source of fullers' earth was Eng- land, but a largely increased demand has resulted in the discovery of large quantities on American soil, the more important localities thus far developed being Bakersville, California; Gadsden County, Florida, and Custer County, South Dakota. The more important foreign sources are Bala, in North Wales, and Buckingham and Surrey, in England. The celebrated beds at Nutfield, near Redhill, Surrey, England, occur in Cretaceous formations, a section of which is here given. 1 Folkstone beds, gray and iron shot sand . 15 ft. Buff sandy clay with greensand 15 " Soft sandstone 4 " Sandgate beds Greenish sandy clay. J Sandstone 12 Fullers' earth. . 8 The fullers' earth bed sometimes reaches a thickness of 12 feet. The upper portion is, as a rule, oxidized to a brownish color by the action of percolating water, the lower portion being blue. In addition to the analyses given on p. 250 the following are of interest as showing the relative amounts of soluble and insoluble matters. 2 BLUE EARTH. (Dried at 100 C.) Insoluble residue 69.96% Fe 2 O 3 248% A1 2 3 346% CaO 5-87% MgO 1.41% P 2 5 - 2 7% S0 3 0.05% NaCl 0.05% Kp < 0.74% H 2 O (combined) iS-57% 99.86% Insoluble Residue. fSi0 2 .. Al,0 r . aS I MgO.. 69.96% 1 H. B. Woodward, Geology of England and Wales, p. 371. 2 P. G. Sanford, Geological Magazine, Vol. VI, 1889, pp. 456 and 526. FIG. i. FIG. 2. PLATE XX. Microsections showing Appearance of (i) Clay (Bentonite), Albany, Wyoming, (2) Fullers' Earth. [U. S. National Museum.] SILICATES. YELLOW EARTH. (Dried at 100 C.) 249 .. 76.1^%- Insoluble Residue, f SiO tjo 37%i Fe,O. . 2.41% ALO~ TO o^ Con- stituents. Smectite from Fullers' Earth gate.(&) & v^\ tJOi rC^j" ^ O Fullers* Earth land.(rf) ^ it fa 6i || l| ll fo Fullers' Earth tur County, Fullers' E Fairborn ' kato.(g) W 5flH rt "w FeO 3.85 Water, H 2 O O.2O Arsenic oxide ......... I.2S Residual clay (kaolin) 1.34 According to State Commissioner of Mines Harry A. Lee, tung- sten in the form of wolfram occurs in several counties in Colorado. In Boulder and Gilpin counties it has been found in veins in a com- plex of granite, gneiss, and schist, where it occurs in small pockets or streaks disseminated through fissure veins with other minerals from which it can, as a rule, be readily separated, owing to its greater specific gravity. In Osceola County, Nevada, tungsten in the form of hubnerite occurs in veins varying from 6 to 36 inches in width, and having a strike north 70 east and a dip of 65 northwest. The veins are in granite with a well-defined selvage and carry quartz as the prin- cipal gangue. Altogether five veins are known. The hiibnerite is found in crystals and masses with very pro- nounced cleavage planes from 2 to 4 inches in length and i to 3 inches in width. It also occurs in fine grains and irregular bodies, the quartz and hubnerite having apparently been deposited con- temporaneously. In a few instances scheelite has been found as- sociated with the hubnerite. A little pyrite and fluorite are also occasionally met with. The ore thus far shipped is stated to have averaged from 65 to 70 per cent of WOs. 1 In Arizona, tungsten ore, also in the form of hubnerite, occurs, according to W. P. Blake, in the granite hills of the Dragoon Moun- tains, about 6 miles north of Dragoon Summit Station on the Southern Pacific Railway in Cochise County. 1 Fred. D. Smith, Engineering and Mining Journal, March i, 1902, p. 304; F. B. Weeks, aist Annual Report of the U. S. Geological Survey, 1899-1900, Part VI, P- 3 J 9- NIOBATES, TANTALATES, AND TUNGSTATES. 257 The veins are nearly vertical and generally traverse the granitic gneiss in the direction of the rude structural bedding planes. They are from a few inches to 2 or 3 feet in width. The gangue mate- rial is quartz, throughout which the hiibnerite occurs, somewhat irregularly disseminated, sometimes in patches or bunches centrally disposed with quartz on either side, and sometimes disseminated from side to side or in layers or bunches in close contact with the continuous walls. The hiibnerite itself is in the form of large tubular blocks or thick plates, often with a somewhat radial arrangement, penetrating the solid gangue of white quartz. Masses of all sizes up to 500 pounds in weight have been reported. The color of the mineral is light brownish red, thin films or plates seen by trans- mitted light being of a ruby- red color. Aside from quartz, which forms the prevailing gangue mineral, the presence of a little fluorspar and mica has been noted. Uses. See under Scheelite, below. 5. SCHEELITE. This is calcium tungstate, consisting when pure of some 80.6 per cent tungsten trioxide (WO 3 ) and 19.4 per cent lime; usually, however, carrying from i to 8 per cent of molybdic oxide (MoO 3 ). The mineral is white and translucent, sometimes yellow and brownish in color, with a hardness of 4.5-5, gravity 6, and a tendency to cleave into octahedral forms. Scheelite is much less common in its occurrence than wolfram, the only locality of any apparent commercial importance which has thus far been reported being at Trumbull, Connecticut. This deposit was described in considerable detail by Dr. Adolf Gurlt at a meeting of the International Engineering Congress in August, 1983, and by Dr. W. H. Hobbs in the Annual Report of the U. S. Geological Survey for 1900-1901. The exact locality is near Long Hill Station on the Housatonic Railroad in Trumbull Parish, Fairfield County, about 8 miles from the city of Bridgeport. The country rock is a metamorphic amphi- bolic gneiss of a dark, blackish color, overlying a crystalline lime- stone, and this in turn overlying a second hornblendic gneiss, the main mass of the ore being segregated along the line of contact 25 8 THE NON-METALLIC MINERALS. between the limestone and the hornblendic gneiss, the latter being considered by Hobbs as an altered igneous rock and the deposit as a whole, therefore, a contact deposit. In the main opening the fresh contact rock between the gneiss and the limestone is a massive quartz-zoisite-epidote-hornblende rock, throughout which the scheelite is irregularly disseminated and often scattered in crystalline masses which are sometimes as large as one's fist. Associated with the scheelite is more cr less pyrite. With the scheelite are numerous crystals of wolframite which are, however, in all cases pseudomorphous. A considerable amount of capital has been expended in prospect- ing and in the erection of works for concentrating, but, so far as the present writer has information, a comparatively small amount of pure scheelite has, thus far been produced. The mining of scheelite being a somewhat uncommon industry, it may not be out of place to dwell a little in detail upon the method of extracting the ore and its concentration. According to the authority quoted, the method of mining at the summit opening has consisted in removing the upper bed of horn- blende along the gently easterly-dipping contact plane from the point where it outcrops at the surface. At favorable localities pits have been sunk for a further distance of a few feet, in order to remove the chert-bearing contact rock just below this floor. The larger rocks obtained by blasting are broken with sledges and the picked ore sent to the mill, whi.ch is built on a steep incline, where it is passed through a Blake crusher having a capacity of about 10 tons per hour. The crushers deliver their deposit to two corresponding setr of Cornish rolls running one-fourth inch apart and having a 22-inch diameter and 1 6-inch face. These rolls discharge the material to an endless belt elevator which carries it to the top of the mill and delivers it to a pair of revolving screens 36 inches in diameter and 8 feet in length and which have a mesh of one-eighth inch square. A considerable portion of the dust produced in crushing is here drawn out by a current of air, which passes under the screens. The portions of the material refused by these screens are carried by gravity to a pair of belted high-speed rolls of 30 inches diameter and 1 8-inch face, running one-eighth NIOBATES, TANTALATES, AND TUNGSTATES. 259 inch apart, and are from them returned to the elevator and again passed through the screens. After this second screening the material passes to a pair of Wolff gyrating screens of 40, 60, and 90 meshes to the inch, respectively. Concentration is effected by a dry process in what is known as the Hooper Pneumatic Concentrating Machine, which delivers the concentrates clean and leaves very little scheelite in the tailings. Uses. Tungsten is mainly used in the manufacture of the so-called self-hardening steel, the material being introduced either as a ferro-tungsten or as the powdered mineral. This tungsten steel is said to be particularly adaptable to the manufacture of cutting tools, which can be used even when heated to temperatures that would destroy the temper of the ordinary carbon steel. It is also used in the preparation of tungstic acid and sodium tungstates, and attempts have been made to utilize it in porcelain glazes, though thus far without much success. The production of tungsten ore in the United States during 1901 amounted to some 179 short tons of concentrates, valued at $27,720. During this same year there were manufactured 76,000 pounds of metallic tungsten, 13,000 pounds of ferro-tungsten, and 3,000 pounds of tungstic acid and sodium tungstate, amounting altogether to 92^000 pounds. The price of the tungsten metal in 1901 varied from 58 to 64 cents per pound, of the ferro-tungsten from 27 to 31 cents per pound. The price of the ore ranged from $102 to $333 per ton, according to quality, the ores, as a rule, carrying from 60 to 75 per cent of WO .* There has been a very marked falling off in the price of both alloys and salts of tungsten within a very few years, though the price of high-grade ore still remains at a very considerable figure. BIBLIOGRAPHY. J. PHILLP. Tungsten Bronzes. Journal of the Society of Chemical Industry, I, 1882, p. 152. The Use of Wolfram or Tungsten Iron Age, XXXIX, 1887, p. 33. T. A. RICKARD. Tungsten. Engineering and Mining Journal, LIII, 1892, p. 448. 1 These figures are taken from the Mineral Industry for 1901. 2 6o THE NON-METALLIC MINERALS. T. A. RICKARD. Wolfram Ore. Iron Age, XL, 1892, p. 229. ADOLF GURLT. On a Remarkable Deposit of Wolfram Ore in the United States. Transactions of the American Institute of Mining Engineers, XXII, 1893, p. 236. See also Engineering and Mining Journal, LVI, 1893, p. 216. F. CREMER. The Place of Tungsten in the Industries. Iron Age, LVI, 1895, p. 536. HENRI MOISSAN. Researches on Tungsten. Minutes of the Proceedings of the Institution of Civil Engineers, CXXVT, 1895-96, p. 481. R. HELMHACKER. Wolfram Ore. Engineering and Mining Journal, LXII, 1896, p. 153. Prof. BODENBENDER. Wolfram in the Sierra de Cordoba, Argentine Republic. Transactions of the North of England Institute of Mining and Mechanical Engineers, XLV, Pt. 3, March, 1896, p. 59. WM. P. BLAKE. Hubnerite in Arizona. Transactions of the American Institute of Mining Engineers, XXVIII, 1898, P- 543- Wolfram Ore. Engineering and Mining Journal, LXVII, March 18, 1899, p. 324. Scheelite in New Zealand. Engineering and Mining Journal, LXIX, June 23, 1900, p. 736. F. B. WEEKS. An Occurrence of Tungsten Ore in Eastern Nevada. 2ist Annual Report of the U. S. Geological Survey, 1899-1900, Pt. VI. FRED D. SMITH. The Osceola, Nevada, Tungsten Deposits. Engineering and Mining Journal, LXXIII, March, 1902, pp. 304, 305. J. D. IRVING. Some Recently Exploited Deposits of Wolframite in the Black Hills of South Dakota. Transactions of the American Institute of Mining Engineers, XXXI, 1902, pp. 683-685. VIII. PHOSPHATES AND VANADATES. i. APATITE; ROCK PHOSPHATE; GUANO; ETC. Phosphorus is one of the most widespread of the elements, and is apparently indispensable to both animal and vegetable life. In nature it occurs in various compounds, by far the more common being the phosphates of calcium and aluminum, such as are com- mercially used as fertilizers. These in various conditions of im- purity occur under several forms, some distinct and well defined, others illy denned and passing by insensible gradations into one another, but all classed under the general term of phosphates. Their origin and general physical properties are quite variable, and any attempt at classifying must be more or less arbitrary. For PHOSPHATES. 261 our present purposes it is sufficient that we treat them under the heads of mineral phosphates and rock phosphates, as has been done by Dr. Penrose. 1 These two classes are then subdivided as below : . . \ Fluor-apatites . 2 JAP atltes \ Chlor-apatites. (I) Mineral phosphates 2 ... \ [ Phosphorite. I Amorphous nodular phosphates loose or cemented into conglomerates. . Phosphatic limestones. (II) Rock phosphates -j ( Soluble guanos. Guanos 1 Leached guanos. Bone beds. Apatite. Under the name of apatite is included a mineral composed essentially of phosphate of lime, though nearly always carrying small amounts of fluorine or chlorine, thereby giving rise to the varieties ftuor-apatite and chlor-apatite. The mineral crystal- lizes in the hexagonal system, forming well-defined six-sided elon- gated prisms of a green, yellow, rose, or reddish color, or sometimes quite colorless. It also occurs as a crystalline granular rock mass. The hardness is 4.5 to 5; specific gravity, 3.23; luster, vitreous. Apatite in the form of minute crystals is an almost universal con- stituent of eruptive rocks of all kinds and all ages. It is also found in sedimentary and metamorphic rocks as a constituent of veins of various kinds, and is a common accompaniment of beds of mag- 1 Bulletin No. 46 of the U. S. Geological Survey. 2 Fuchs (Notes Sur la Constitution des Gites Phosphate de Chaux) divides the natural phosphates into three classes. In the first the phosphatic material is concen- trated in sedimentary beds; in the second it is disseminated throughout eruptive rocks, and in the third it constitutes entirely or partially the material filling veins and pockets. That found in sedimentary beds occurs in rounded and concretionary masses called nodules. In eruptive and metamorphic rocks the phosphate occurs in the crystalline form of apatite, sometimes isolated or grouped in aggregates. In veins the phosphate occurs massive and in pockets, crystalline, but not in distinct crystals; rather as globular and radiating masses. To such the name phosphorite is given. The three varieties show a like variation in solubility, the amorphous phos- phates being soluble in citrate or oxalate of ammonia to the extent of 30 to 50 per cent; the phosphorites to the extent of only 15 to 30 per cent, and the apatite scarcely at all. The amorphous phosphates alone have proven of value for direct application to soils, the other varieties needing previous treatment to render them soluble. 262 THE NON-METALLIC MINERALS. netic iron ore. It is only when occurring segregated in veins and pockets, either in distinct crystals or as massive crystalline aggregates, as in Canada and Norway, that the material has any great economic value. The average composition of the apatites, as given in the latest edition of Dana's Mineralogy, is as follows: Variety. P 2 5 . CaO. F. Cl. Chlor-apatite. . 41. te& 6.8 or Ca P O 8 894 +CaCl 10 6 Fluor-apatite 42.^ cc.c 3.8 or CaP O a , 02 2t + Ca. 7 7? The name phosphorite covers a material of the same composi- tion as apatite, but occurring in massive concretionary and mam- millary forms. The name was first used by Kirwan in describing the phosphates of Estremadura, Spain, which occur in veins and pockety masses in Silurian schists, as noted later. Rock Phosphate. The general name of rock phosphate is given to deposits having no definite composition but consisting of amorphous mixtures of phosphatic and other mineral matter in indefinite proportions. Here would be included the amorphous nodular phosphates like those of our Southern _ Atlantic States, phosphatic limestones and marls, guano, and bone-bed deposits These are so variable in character that no satisfactory description of them as a whole can be given. The name coprolite is given to a nodular phosphate such as occurs among the Carboniferous beds of the Firth of Forth in Scotland, and which is regarded as the fossilized excrement of vertebrate animals. Phosphatic limestones and marl, as the names denote, are simply limestones and marls containing an appreciable amount of lime in the form of phosphate. Such are rarely sufficiently rich to be of value except in the im- mediate vicinity, owing to cost of transportation. Guano is the name given to the accumulations of sea-fowl excretions, such as occur in quantities only in rainless regions, as the western coast of South America. The most noted deposits are on small islands off the coast of Peru. The material is of a white-gray and yellowish color, friable, and contains some 20 or more per cent of phosphate of lime, 10 to 12 per cent of organic matter, 30 per cent of ammonia Salts, and 20 per cent of water. Through prolonged exposure to PHOSPHATES. 263 the leaching action of meteoric waters, like deposits in the West India Islands have lost all their ammonia salts and other soluble constituents and become converted into insoluble phosphates, or leached guanos like those of the Navassa Islands. Origin and occurrence. The origin of the various forms of phos- phatic deposits has been a subject of much speculation. Their occurrence under diverse conditions renders it certain that not all can be traced to a common source, but are the result of different agencies acting under the same or different conditions. By many, all forms are regarded as being phosphatic materials from animal life, and owing their present diversity of form to the varying con- ditions to which they were at the time of formation or have since been subjected. This, however, as long since pointed out, is an uncalled-for hypothesis, since phosphatic matter must have existed prior to the introduction of animal life, and there is no reason to suppose it may not, under proper conditions, have been brought into combination as phosphate of lime without the intervention of life in any of its forms. The almost universal presence of apatite in small and widely disseminated forms in eruptive rocks of all kinds and all ages would seem to declare its independence of animal origin as completely as the pyroxenic, feldspathic, or quartzose constituents with which it is there associated. The occurrence of certain of the Canadian apatites as noted later, in veins and pockets, sometimes with a banded or concretionary structure and blending gradually into the country rock, is regarded by some as strongly suggestive of an origin by deposition from solution, that is, by a process of segregation of phosphates from the surrounding rock contemporaneously with their metamorphism and crystallization. Dr. Ells, of the Canadian survey, would regard those occurring in close juxtaposition with eruptive pyroxenites as due to combina- tion of the phosphoric acid brought up in vapors along the line of contact with the calcareous materials in the already softened gneisses. This explanation as well as others will perhaps be better understood in the part of this work relating to localities. On the other hand, the presence of apatite in crystalline form associated with beds of iron ore, as in northern New York, has been regarded by Prof. W. P. Blake and others as indicative of an organic and sedimentary 264 THE NON-METALLIC MINERALS. origin for both minerals. The Norwegian apatite from its asso- ciation with an eruptive rock (gabbro) has been regarded as itself of eruptive origin. The phosphorites, like the apatites, occur in commercial quan- tities mainly among the older rocks, and in pockets and veins so situated as to lead to the conclusion that they are secondary products derived by a process of segregation from the inclosing material. Davies regards the Bordeaux phosphorites occurring in the Jurassic limestones of Southern France as the result of phosphatic matter deposited on the rocky floor of an Eocene ocean, from water largely impregnated with it. Others have considered them as geyserine ejections, or due to infiltration of water charged with phosphatic matter derived from the bones in the overlying clays. Stanier, on the other hand, regards the phosphorites of Portugal as due to segregation of phosphatic matter from the surrounding granite, the solvent being meteoric waters. These deposits are regaxded as superficial and limited to those portions of the rock affected by surface waters. The origin of the amorphous, nodular, and massive rock phos- phates can, as a rule, be traced more directly to organic agencies. All things considered, it seems most probable that the phosphatic matter itself was contained in the numerous animal remains, which, in the shape of phosphatic limestones, marls, and guanos, have accumulated under favorable conditions to form deposits of very con- siderable thickness. Throughout these beds the phosphatic matter would, in most cases, be disseminated in amounts too sparing to be of economic value, but it has since their deposition been con- centrated by a leaching out by percolating waters of the more soluble carbonate of lime. Thus H. Losne, in writing of the nodular phos- phates occurring in pockety masses in clay near Doullens (France), argues that the nodules as well as the clay itself are due to the de- calcification of preexisting chalk by percolating meteoric waters. In this connection it is instructive to note that phosphatic, nodules, in size rarely exceeding 4 to 6 cm., were dredged up during the Challenger expedition from depths of from 98 to 1,900 fathoms on the Agulhas Banks, south of the Cape of Good Hope. These are rounded and very irregular capricious forms, sometimes angular, PHOSPHATES. 265 and have exteriorly a glazed appearance, due to a thin coating of oxides of iron and manganese. The nodules yield from 19.96 to 23.54 per cent P 2 O 5 . In those from deep water there are found an abundance of calcareous organic remains, especially of rhizopods. The phosphate penetrates the shell in every part, and replaces the original carbonate of lime. The nodules are most abundant apparently where there are great and rapid changes of temperature due to alternating warm and cold oceanic currents, as off the Cape of Good Hope and the eastern coast of North America. Under such conditions, together with perhaps altered degrees of salinity, marine organisms would be killed in great numbers, and by the accumulation of their remains would, it is believed, furnish the necessary phosphatic matter for these nodules. It seems probable that the Cretaceous and Tertiary deposits in various parts of the world may have formed under similar conditions. Hughes has described 1 phosphatic coralline limestones on the islands of Barbuda and Aruba (West Indies), as having undoubtedly originated through a replacement of the original carbonic by phos- phoric acid, the latter acid being derived from the overlying guano. The phosphatic guano has, however, now completely disappeared through the leaching and erosive action of water, leaving the coral rock itself containing 70 to 80 per cent phosphate of lime. Hayes 1 regards the Tennessee black phosphates as due to the slow accumulation on sea bottoms of phosphatic organisms (Lin- gulae), from which the carbonate of lime was gradually removed by the leaching action of carbonated waters, leaving the less soluble phosphate behind. The white bedded phosphates of Perry County, in the same State, are regarded as a product of secondary replace- ment that is, as due to phosphate of lime in solution, replacing the carbonate of lime of preexisting limestones, as in the case noted above. The source of the phosphoric acid, whether from the over- lying Carboniferous limestones or from the older Devonian and Silurian rocks, is not, however, in this case apparent. 1 Quarterly Journal of the Geological Society of London, XLI, 1885, p. 80. 'Sixteenth Annual Report of the U. S. Geological Survey. 1894-95, Pt. 4, p, 620; Seventeenth Annual Report U. S. Geological Survey, 1895-96, Pt. 2, p. 22. 2 66 THE NON-METALLIC MINERALS. Teall has shown * that some phosphatic roeks from Clipperton Atoll, in the northern Pacific, are trachytes in which phosphoric acid has replaced the original silica. The replacement he regards as having been effected through the agency of alkaline (principally ammonium) phosphate which has leached down from overlying guano. A microscopic examination of the rock in thin sections showed that the replacing process began with the interstitial matter, then extended to the feldspar microlites, and lastly the porphyritic sanidin crystals. The gradual change in the relative proportion of silica and phosphoric acid, as shown by analyses of more or less altered samples, is shown below, No. I being that of the unaltered rock and II and III of the altered forms: Constituents. I II. III. SiO, ^4 O 43.7 2.8 P,CX 8.4 I7-O *8.s Loss on ignition 3.8 12.2 2^.O From a comparison of these rocks with those of Redonda, in the Spanish West Indies, it is concluded that the latter phosphates have likewise resulted from a similar replacement in andesitic rocks. In this connection reference is made to the work of M. A. Gautier, 2 in which he describes the formation of aluminous phosphates in caves through the action of the ammonium phosphate arising from decomposing organic matter on the clay of the floor of caverns. (See under Occurrences.) The guanos, as noted elsewhere, owe their origin mainly to the accumulations of sea-fowl excretions. Such deposits when un- leached, are relatively poor in phosphatic matter and rich in salts of ammonia. Where, however, subjected to the leaching action of rains the more soluble constituents are carried away, leaving the less soluble phosphates, together with impurities, in the shape of alumina, silica, and iron oxides to form the so-called leached guanos of the West India Islands. As stated in the descriptions 1 Quarterly Journal of the Geological Society of London, LIV, 1898, p. 230. 3 Formation des Phosphates Naturels d' Alumina et de Fer, Comptes Rendus de 7 Academic des Sciences, Paris, CXVI, 1893, p. 1491. PHOSPHATES. 267 of localities, guano deposits are not infrequently of a thickness such as to cause their origin as above stated to seem well-nigh in- credible were there not sufficient data acquired within historic times to demonstrate its accuracy beyond dispute. Thus it is said 1 that in the year 1840 a vessel loaded with guano on the island of Ichabo, on the east coast of Africa. During the excavations which were necessary the crew exhumed the dead body of a Portuguese sailor, who, according to the headboard on which his name and date of burial had been carved with a knife, had been interred fifty- two years previously. The top of this headboard projected 2 feet above the original surface, but had been covered by exactly 7 feet of subsequent deposit of guano. That is to say, the deposition was going on at the rate of a little over an inch and a half yearly. LOCALITIES OF PHOSPHATES. Canada. According to Dr. Ells, of the Canadian Survey, 2 the discovery of apatite in the Laurentian rocks of eastern Canada was first made in the vicinity of the Lievre by Lieutenant Ingall in 1829, though it was not until early in 1860 that actual mining was begun. The mineral occurs in the form of well-defined crystals in a matrix of coarsely crystalline calcite and in vein-like and pockety granular masses along the line of contact between eruptive pyroxenites and Laurentian gneisses. The first form is the predominant one for Ontario only, the second for Quebec. From a series of openings made at the North Star Mine, in the region north of Ottawa, it appears that the massive coarsely crystalline granular apatite follows a somewhat regular course in the pyroxenite near the gneiss, but occurs principally in a series of large bunches or chimneys connected with each other by smaller strings or leaders. Sometimes these pockety bunches of ore are of irregular shape and yield hundreds of tons, but present none of the characteristics of veins, either in the presence of hanging or foot walls, while many of the masses of apatite appear to be completely isolated in the mass of pyroxenite, though possibly there may have been a connection through small 1 R. Ridgway, Science, XXI, 1893, p 360. ' 2 The Canadian Mining and Mechanical Review, March, 1893. OF THE UNIVERSJTY 268 THE NON-METALLIC MINERALS. fissures with other deposits. The lack of any connection between these massive apatites and the regularly stratified gneiss is evident, and their occurrence in the pyroxenite is further evidence in support of the view that these workable deposits are not of organic origin, but confined entirely to igneous rocks. In certain cases where a supposed true- vein structure has been found, such structure can be explained by noticing that the deposits of phosphates occur, for the most part at least, near the line of contact between the pyroxenite and the gneiss. By far the greater part of the Canadian apatite thus far mined has been from the Ottawa district of Quebec, where it is mined or quarried .mainly from open cuts and shafts. The principal fields lie in Ottawa County, Province of Quebec, and Leeds, Lanark, Frontenac, Addington, and Renfrew counties, Province of Ontario. The first consists of a belt running from near the Ottawa River on the south for over 60 miles in a northerly direction through Bucking- ham, Portland, Templeton, Wakefield, Denholm, Bowman, Hincks, and other townships to the northward have an average width of 15 to 25 miles. The second belt runs from about 15 miles north of the St. Lawrence River in a northerly direction to the Ottawa River, a distance of about 100 miles, and varies from 50 to 75 miles in breadth. Davies gives the following table as showing the average composi- tion of the Canadian phosphates: Constituents. I. II. III. IV. V. VI. Moisture, water of combination, and loss on ignition o 62 O IO on I OO o 89 i 8* Phosphoric acid 3 ? r j 4.1 ^4 37 68 ?o 84 20 C 3 1.03 3i 87 Lime. 4.6 14. CA 74. c i 04 42 72 4.4 26 6 L -/ 43 62 Oxide of iron, alumina) fluorine, etc. Insoluble siliceous matter 7.83 1 1 QO 3-3 O CJQ 6.88 4..2Q I3--3 2 I 2 O3 12.15 IO 17 9.28 1 3 c;o Equal to tribasic phosphate of lime IOO.OO 73. 1 1 ; 100.00 00.68 IOO.OO 82.21; IOO.OO 67.72 100.00 7 1. 01 100. IO 6o.3iJ Norway. The principal apatite fields lie along the coast in the southern portion of the peninsula between Langesund and Arendal. The material occurs in crystals and crystalline granular aggregates of a white, yellow, greenish, or red color in veins and pockets em- PHOSPHATES. 269 bedded in the mass of an eruptive gabbro, near the line of contact of the gabbro and adjacent rocks, in the country rock itself in the immediate vicinity of the gabbro, and in coarse pegmatitic veins which are cut by the gabbro. The largest veins are in the mass of the gabbro itself or near the line of contact. Where the apatite occurs in the gabbro the latter is, as a rule, altered into a hornblende scapolite rock. The principal associated minerals are quartz, mica, tourmaline, scapolite, feldspars, rutile, and magnetic and titanic iron and sulphides of iron and copper. The country rock is gneiss, schist, and granite. The mineral belongs to the variety called fluor- apatite, as shown by the following analysis from Dr. Penrose's Bulletin: APATITE FROM ARENDAL. Phosphoric acid (P^jOg) 1 42.229 Fluorine 2 34 I 5 Chlorine 3 0.512 Lime (CaO) 49.96 Calcium 3-884 100.000 The Norway apatites have been mined according to Penrose since 1854, the earliest workings being at Kragero. According to Davies, however, the discovery of deposits that could be profitably worked dates only from 1871. The distribution of the material is very uncertain and irregular, and the value of the deposits can not be foretold with any great approximation to accuracy. A large mass of this material, weighing nearly 2 tons, is on exhibition in the department of economic geology in the National Museum. United States. Nodular phosphatic deposits are found at inter- vals all along the Atlantic coast of the United States, from North Carolina down to the southern extremity of Florida. The North Carolina deposits occur principally in the counties of Sampson, Duplin, Pender, Onslow, Columbus, and New Hanover, all in the southeastern part of the State. The deposits are of two kinds : (i) a 1 Equal 92.189 per cent tribasic phosphate. 2 Equal 7 01 per cent fluoride of calcium. 8 Equal 0.801 per cent chloride of calcium. 270 THE NON-METALLIC MINERALS. nodular form overlying the Eocene marls and consisting of phos- phate nodules; sharks' teeth, and bones embedded in a sandy or marly matrix, and (2) as a conglomerate of phosphate pebbles, sharks* teeth, bones, and quartz pebbles, all well rounded and cemented together along with grains of greensand in a calcareous matrix. The beds of the first variety usually overlie strata of shell marl, though this is sometimes replaced by a pale green indurated sand. The two following sections will serve to illustrate their mode of occurrence : SAMPSON COUNTY. DTJPLIN COUNTY. (1) Soil, sand, or clay, 5 to 10 feet. (i) Sandy soil, i to 10 feet. (2) Shell marl, 5 to 10 feet. (2) Nodule bed, i to 2 feet. (3) Bed with phosphate nodules, I to 3 (3) Shell marL feet. (4) Sea-green sandy marl, 2 to 4 feet. (5) Ferruginous hardpan, 6 to 12 inches. (6) Interstratified lignites and sands as in (4). The nodules are of a lead-gray color, varying in size from that of a man's fist to masses weighing several hundred pounds. In texture they vary from close compact and homogeneous masses to coarse-grained and highly siliceous rocks distinguished by con- siderable quantities of sand and quartz pebbles sometimes the size of a chestnut. Occasionally the nodules, which as a rule are of an oval flattened form, contain Tertiary shells. The second or con- glomerate variety occurs mainly in New Hanover and Fender counties, the beds in some instances being 6 feet in thickness, though usually much less. The following section, taken from Dr. Penrose's Bulletin, shows their position and association as displayed at Castle Hayne, New Hanover County. "(i) White sand, o to 3 feet. " (2) Brown and red ferruginous sandy clay, or clayey sand, i to 3 feet. "(3) Green clay, 6 to 12 inches. "(4) Dark -brown indurated peat, 3 to 12 inches. "(5) White calcareous marl, o to 2 feet. "(6) White shell rock, o to 14 inches. "(7) Phosphatic conglomerate, i to 3 feet. PHOSPHATES. 271 " (8) Gray marl containing smaller nodules than the overlying beds, 2^ to 4^ feet. " (9) Light- colored, calcareous marl, containing nodules which are smaller than those in the overlying beds, which grow fewer and smaller at a depth. Many shells." The phosphatic nodules in this conglomerate are kidney and egg shaped and sometimes make up as much as three-fourths the contents of a bed ; usually, however, the proportion is smaller, and sometimes there are none at all. The mass as a whole does not contain more than 10 to 20 per cent phosphate of lime, but it is said to have been successfully used as a fertilizer. The individual nodules may be richer in phosphatic matter on the outer surface than toward the center. Aside from the phosphatic layer as described above, phosphatic nodules are found in large quantities in the beds of rivers of these districts, where they have accumulated through the washing action of flowing water, the finer sand, clay, and gravel having been carried away. Such phosphates naturally do not differ materially from those on land except that they are darker in color and sometimes more siliceous. The deposits of South Carolina are of low grade compared with some others, but for many years were more generally used than any other American phosphate. This popularity was due not only to the cheapness of the phosphate ($5 to $6 a ton in 1886), but to the many good qualities of the low-grade acid phosphate made from it. Of late years the Florida phosphates have gradually replaced them. Phosphates in the form of nodules and phosphatic marls and greensands occur in Alabama in both the Tertiary and Cretaceous formations. Their geographical distribution is therefore limited to areas south of the outcrops of the lowest Cretaceous beds which stretch in a curve from the northwest corner of the State across near Fayette, Courthouse, Tuscaloosa, Centerville, and Wetumpka, to Columbus, Georgia. As all the Cretaceous and Tertiary beds have a dip toward the Gulf of from 25 to 40 feet to the mile, the phosphate-bearing strata appear at the surface only in a compara- tively narrow belt along the line above indicated and are to be found only at gradually increasing depths below at points to the southward. 272 THE NON-METALLIC MINERALS. Phosphatic nodules and marls of the Tertiary occur in four different horizons: The Black Bluffs and Nantehala groups of the Lignitic; in the white limestone, and in eastern Alabama, at Ozark, in strata of the Claiborne group. Selected nodules run as high as 27 per cent of phosphoric acid, and marls as high as 6.7 per cent. The Tertiary is not, however, regarded by Professor Smith as a promising source of commercial phosphates in the State. In the Cretaceous the phosphates occur in the transition beds both above and below the so-called Rotten Limestone existing as nodules, shell casts, phosphatic limestones, marls, and greensands. The nodules have essentially the characteristics of those of South Caro- lina. The principal phosphate region of Florida, as known to-day, comprises an area extending from west of the Apalachicola River eastward and southward to nearly 50 miles south of Caloosahatchee River, as shown on the accompanying map. 1 According to Mr. Eldridge, the deposits comprise fou^ distinct and widely different classes of commercial phosphates, each having a peculiar genesis, a peculiar form of deposit, and chemical and physical properties such as readily distinguish it from any of the others. According to their predominant characteristics or modes of occur- rence, these classes have come to be known as hard-rock phosphates, soft phosphate, land pebble or matrix rock, and river pebble. With the exception of the soft phosphates, they underlie distinct regions, each class being separate or but slightly commingling with one another. The hard-rock phosphate is a hard, massive, close- textured, homogeneous, light-gray rock, showing large and small irregular cavities, which are usually lined with secondary mam- millary incrustations of nearly pure phosphorite. The deposits, which average some 36.65 per cent P 2 O 5 , lie in Eocene and Miocene strata, occurring in the first named as a bowlder deposit in a soft matrix of phosphatic sands, clays, and other material, resulting from the disintegration of the hard rock and constituting the soft phosphates. They underlie sands of from 10 to 20 feet in thickness, and have been penetrated to a depth of 60 feet. The 1 Preliminary sketch of Phosphates of Florida, by George H. Eldridge. X : REGIONS or PHOSPHATE >.. d Ho<-k i A PLATE XXL Map showing Phosphate Regions of Florida. [U. S. National Museum.] \ PHOSPHATES. 273 phosphate deposit proper is white, the bowlders of rounded and irregular outline, varying in diameter from 2 or 3 inches to 10 feet. None of the hard- rock deposits of the Eocene originated in the positions they now occupy. The Miocene hard-rock phosphates, on the other hand, lie in regular bedded deposits in situ, as well as in bowlders. The beds lie horizontal but a few feet below the sur- face, being covered only by superficial sand. They are, as a rule, but from 4 feet to 5 feet thick. The name soft rock, or soft phos- phate, as above indicated, is given to the softer material associated with the hard rock, which in part results from the disintegration of the last named. It is also applied somewhat loosely to any variety not distinctly hard. It therefore varies greatly in color, chemical and physical characteristics, and rarely carries more than '20 to 25 per cent of P 2 O 5 . The name land-pebble phosphate includes pebble from deposits consisting of either earthy material carrying fossil remains, grains of quartz, and pisolitic grains of lime phosphate, or else of a material resembling in texture and other characteristics the hard-rock phos- phate.. The individual pebbles vary in size up to that of the English walnut, are normally white, but when subjected to percolating water become dark gray or nearly black. The exteriors are quite smooth and glossy; such yield on an average some 30 to 35 per cent P 2 O 5 . The river-pebble varieties differ from the last mainly in mode of occurrence, being found, as the name would indicate, in the beds of streams, where presumably they have accumulated through the washing away of finer and lighter materials. They are most abun- dant in the Peace, Caloosahatchee, Alafia, and other rivers entering the Gulf south of Tampa and Hillsborough bays, though the Withla- coochee, Aucilla, and rivers of the western part of the State, carry also a mixture of pebbles, hard-rock fragments, and bones derived from the various strata through which they have cut" their channels. The pebbles of the Western rivers show a very uniform composition, and range from 25 to 30 per cent phosphoric anhydride (P 2 O 5 ), or about 65 per cent of phosphate of lime, the impurities being mainly siliceous matter, carbonate of lime, alumina, and iron oxides. Phosphatic deposits of high grade and covering considerable areas in western middle Tennessee were discovered during the 274 THE NON-METALLIC MINERALS. latter part of 1893. Since then development has been rapid, and the State now stands second in rank, as a producer, being exceeded only by Florida. The general distribution of the beds is shown in the accompanying sketch map (PL XXI), while their varying thickness is shown in the columnar sections on PL XXII. The essential facts regarding these deposits have been summarized by C. W. Hayes 1 from whose reports a large part of the material here -given is compiled. The deposits are classified by Hayes as I. Black phosphate (an original deposit). 1. Nodular. 2. Bedded, including oolitic, compact conglomeratic, and shaly varieties. II. White phosphate (a secondary deposit). 1. Stony. 2. Breccia. 3. Lamellar. The first of these, the black phosphate, is of Devonian age. The second, the white phosphate, which are altogether secondary deposits, are very recent. The surface rocks of the region include Silurian, Devonian, and Carboniferous beds arranged as follows: Carboniferous Cherty, shaly limestone. D Greensand with phosphatic nodules.. 8-14 inches C Carbonaceous black shale 0-6 feet B Bedded phosphate 0-40 inches A Gray sandstone 0-6 feet Silurian Blue limestone Devonian. The black nodular phosphate occurs in a black shale, in spher- ical to broadly oval and flattened ellipsoidal forms, with smooth surfaces and black color. They are easily detached from the matrix and weather down rapidly to a gray, at times almost white, sand. Their distribution is extremely irregular and they have not yet been found in sufficient abundance to be profitably mined, although individual nodules may contain from 60 to 70 per cent phosphate of lime. The black bedded phosphate, as noted above 3 occurs in several 1 See i6th, lyth, and 2ist Annual Reports, U. S. Geological Survey. PLATE XXII. SECTIONS SHOWING THE RELATIONS OF THE TENNESSEE PHOS- PHATES TO ADJACENT FORMATIONS. Scale: i inch=io feet. TOTTYS BEND, HICKMAN COUNTY. F", F\ Calcareous cherty shale. Blue shale with phosphate nodules. Black shale. Oolitic phos- phate, gray, 40". Oolitic phos- phate, blue. Phosnhatic limestone, 18". Blue flaggy limestone. Calcareous cherty shale. Black shale. Phosphatic sandstone and conglom- erate, 22". Blue flaggy limestone. FALL BRANCH, HICKMAN COUNTY. Calcareous cherty shale. Black shale with beds of phosphatic nodules. Oolitic phos- phate, 36", with conglomerate streaks. Phosphatic limestone. Blue flaggy limestone. Cherty limestone. Black shale. i I Black sandy phosphate. 20". Gray sand- stone. Chert nodules. Calcareous sandstone. Blue flaggy limestone. CENTERVILLE, HICKMAN COUNTY. tr t- Calcareous cherty shale. Black shale. Black phos- phate, 28". Blue clay shales. Blue flaggy limestone. 4 Cherty Emestone. Black shale with phosphate nodules. Black shaly, sandy phos- phate, 54". Yellow sandy shale. Massive gray sandstone. Blue flaggy limestone. PHOSPHATES. 275 varieties. The oolitic form has in the weathered outcrop the ap- pearance of a rusty porous sandstone. A close inspection of the unweathered rock shows it to be made up of rounded or flattened ovules of a blue-black color and small fossil shells or casts of shells embedded in a fine-grained or structureless matrix which, like the ovules, is composed mainly of phosphatic material made dark by carbonaceous matter. ( f The compact phosphate variety resembles a fine-grained car- bonaceous sandstone. When fresh it is of a dark gray to bluish- - black color, but weathers to a buff or dull yellow color, natural joint blocks when broken across often showing a nearly black nucleal portion surrounded by concentric shells of oxidized material of varying shades of brown or yellow. Under the microscope this variety is seen to be made up of small ovules and fossil casts closely packed together without the amorphous matrix noted in the oolitic variety. Closely associated with the above forms is the conglomeratic variety consisting of beds of coarse sandstone and conglomerate containing varying amounts of phosphate. These are black in color and weather brownish, also. The truly phosphatic portion of this variety resembles that of the compact and oolitic forms, but it differs in the presence of varying amounts of quartz, sand, and pebbles. These three varieties of the black bedded phosphate yield on the average some 70 per cent of phosphate of lime. The shaly variety is poorer in phosphoric acid and has the appearance of a dark gray to black shaly sandstone. The distribution of the black phosphate is limited mainly to Hickman, Lewis, and Perry counties, the beds varying in thickness from o to 24 inches. The white phosphates are associated with Carboniferous rocks, though the formation of the phosphate itself is much more recent. The stony variety, as it is called above, is a finely granular gray rock sometimes resembling a quartzitic sandstone, which occurs in more or less regular bands alternating . with thinner bands of chert in a dark shaly siliceous limestone. Thin sections of the phosphate rock, under the microscope, show a ground mass of chalcedonic silica enclosing numerous very minute isotropic forms with the rhombic outlines of calcite but which chemical tests show 276 THE NON-METALLIC MINERALS. to be phosphate. This variety yields from 27 to 33 per cent phos- phate of lime, Ca 3 P 2 O 8 . The breccia phosphate occurs in irregular masses composed of small, angular fragments of the chert embedded In a matrix of the lime phosphate, the chert fragments varying in diameter from a fraction of an inch to 3 or 4 inches. The lamellar variety consists, as the name suggests, of thin parallel plates or layers, sometimes several inches in width of phosphatic material. The white phosphate is limited in its distribution to an area of about 12 square miles in the northern part of Perry County. The probable origin of both the white and black forms has been already given (p. 265). England. Deposits of phosphates sufficiently concentrated for commercial purposes lie near the upper limit of Cambro-Silurian strata in North Wales. According to Davies, the phosphatic material occurs in the form of nodular concretions of a size varying from that of an egg to a cocoanut, closely packed together and cemented by a black slaty matrix. The concretions have often a black highly polished appearance, due to the presence of graphite, but owing to the presence of oxidizing pyrite they sometimes become rusty brown. The concretions carry from 60 to 69 per cent of phosphate of lime; the matrix is also phosphatic. The phosphate beds are highly tilted and are overlaid by gray shales with fossilized echinoderms and underlaid by dark crystalline limestone, which also contains from 15 to 20 per cent of phosphatic material. Davies regards the deposit as an old sea bottom on which the phosphatic matter of Cretaceous and Molluscan life was precipitated and stored during a long period, while certain marine plants may also have contributed their share of phosphatic matter. He thinks it also possible that, as in the Laurentian deposits, the water of the sea may have contained phos- phatic matter in solution to be deposited independently of organic agencies. These phosphated beds are mined at Berwin, where an average production over a space of 360 fathoms was 2 tons 10 hundred- weight of phosphate per fathom, of an average strength of 46 per cent. The nodules average from 45 to 55 per cent of phosphate of lime. Amorphous nodular phosphates also occur in both the Upper PHOSPHATES. 277 and Lower Greensands of the Cretaceous and in Tertiary deposits. Those of the upper beds have been mined in Cambridgeshire and Bedfordshire. The phosphatic material occurs in the form of shell casts, fossils, and nodules, of a black or dark-brown color, of varying hardness, embedded in a sand consisting of siliceous and calcareous matter as well as phosphatic and glauconitic grains. The average composition shows from 40 to 50 per cent of phosphate of lime. The thickness of the nodule-bearing bed is rarely over a foot. The nodules of the Lower Greensands differ from those of the Upper in many details, the more important being their lower percentages of phosphate of lime (from 40 to 50 per cent). They occur in a bed of siliceous sand which itself is not phosphatic. The Tertiary phosphates reach their best development in the county of Suffolk, where they are found at the base of the Coralline and Red Crag groups and immediately overlying the London clays. The beds consist of a "mass of phosphatic nodules and shell casts, siliceous pebbles, teeth of cretaceans and sharks, and many mammal bones, besides occasional fragments of Lower Greensand chert, granite, and chalk flints." The nodules vary in both quality and quantity. They are at times of a compact and brittle nature, while at others they are tough and siliceous. They average about 53 per cent phosphate of lime and 13 per cent phosphate of iron. France. Phosphates of the nodular type occur .in beds of Cre- taceous age in the provinces of Ardennes and Meuse, and to a less extent in others in Northern France; in the department of Cote- d' Or, and along the Rhone at Bellegarde, Seyssel, and Grenoble. As in England, the phosphatic nodules of the northern area, such as are of commercial importance, occur in both the Upper and Lower Greensands. They resemble in a general way the English phos- phates, but are described as soft and porous and easily disintegrat- ing when exposed to the air. Those of the Upper Greensand average some 55 per cent of phosphate of lime. More recently deposits have been described by M. J. Gosselet,' near Fresnoy-le-Grand, in the north of France. The phosphatic material occurs in a zone of gray chalk some 6 feet in thickness 1 Annales de la Societe Geologique du Nord. XXI, 1893, p. 149. 278 THE NON-METALLIC MINERALS. (i^ to 2 meters), and is in the form of concretionary nodules forming a sort of conglomerate in the lower part of the bed. A portion of the chalk is also phosphatic. Phosphatic material (of the type of phosphorites) is found in fissures and pockets in the upper portion of limestones of Middle Jurassic (Oxfordian) age, in the depart- ments of Tarn-et-Garonne, Aveyron, and Zoti, France. The deposits are of two kinds. The first occurring in irregular cavities or pockets never over a few yards long, and the second in the form of elongated leads with the sides nearly vertical. These are generally shallow, and thin out very rapidly at a short distance below the surface. The nodules or concretions are of a white or gray color, waxy luster, and opal-like appearance, and occur in the 'form of tubercular or kidney-shaped masses embedded in ferruginous clay in the clefts of the limestone, or in geodic, fibrous, and radiating forms. The material of this region is known commercially as Bordeaux phosphate, being shipped mainly from Bordeaux. It averages from 70 to 75 per cent phosphate of lime, the impurities being mainly iron oxides and siliceous matter. Gautier 1 describes deposits of phosphates estimated to the amount of 120,000 to 300,000 tons on the floors of the Grotte de Minerve, near the village of Minerve on the northeast flank of the Pyrenees, in Aude, France. The cave proper is in nummulitic limestone of Eocene age, the floors being formed by Devonian rocks. The filling material consists of cave earth and bone breccia below which are the aggregates of concretionary phosphorites and other phosphatic compounds of lime and alumina, the more in- teresting being Brushite, a hydrous tribasic calcium phosphate hitherto known only as a secondary incrustation on guano from the West India Islands, and Minervite, a new species having the formula A1 2 O 3 .P 2 O 5 ,7H 2 O, a hydrous aluminum phosphate, existing in the form of a white plastic clay-like mass filling a vein from a few inches to 2 or more feet in thickness. Germany. According to Davies, the principal phosphate regions of North Germany occupy an irregular area bounded on the north- 1 Annales des Mines, V, 1894, p. 5. PHOSPHATES. 279 east by the town of Weilburg, on the northwest by the Westerwald, on the east by the Taunus Mountains, and on the south by the town of Dietz. The material occurs in the form of irregular nodular masses of all sizes up to masses of several tons weight, embedded in clay which rests upon Devonian limestone and is .overlaid by another stratum of clay. The phosphate-bearing clay varies in thickness from 6 inches to 10 feet. With the phosphate nodules are not infrequently associated deposits of manganese and hematite. Davies regards the deposits as of early Tertiary age. The color of the freshly mined material varies from pale buff to dark brown, varying in specific gravity from 1.9 to 2.8, the quality deteriorating with the increase in gravity. Selected samples of the staple nodules yielded as high as 92 per cent phosphate of lime; but the average is much lower, being but about 50 to 60 per cent phosphate of lime. Belgium. Nodular phosphates belonging to the Upper Cre- taceous formations occur in the province of Hainaut, where they form the basis of an extensive industry. The nodules, which are generally of a brown color and vary in size from the fraction of i to 4 or 5 inches in diameter, lie in a coarse-grained, friable rock called the brown or gray chalk, which itself immediately underlies what is known as the Ciply conglomerate. The phosphate-bearing bed is sometimes nearly 100 feet in thickness, but is richest in the upper 10 feet, where it is estimated the phosphatic pebbles constitute some 75 per cent of its bulk. Below this the bed grows gradually poorer, passing by gradations into the white chalk below. The overlying conglomerate also carries phosphate nodules, which carry from 25 to 50 per cent phosphate of lime. Owing to the hardness of the inclosing rock they are less mined than those in the beds beneath. The mining of phosphates is carried on ex- tensively near the town of Mons, on the lands of the communes of Cuesmes, Ciply, Mesvin, Nouvelles, Spiennes, St. Symphorien, and Hyon. The annual output has gradually increased from between 3,000 and 4,000 tons in 1887 to 85,000 tons in 1894. Other phos- phatic deposits are described * as occurring in the provinces of Antwerp and Liege. 1 Annales de la Societe Geologique de Belgique, XVII, 1890, p. 185. a8o THE NON-METALLIC MINERALS. Spain. Important deposits of phosphorites occur between Logrosan and Caceres, in Estremadura Province. The deposits are in the form of pockets and veins in slates and schists supposed to be of Silurian age; at times a vein is found at the line of contact between the slate and granite. The veins vary in thickness from i to several feet, the largest being some 20 feet and extending for over 2 miles. This is by far the largest of its kind known. As described, the Logrosan phosphate has a subcrystalline structure; sometimes fibrous and radiating. It is soft and chalky to the touch, easily broken, but difficult to grind into a fine powder. An examination under the microscope exhibits conchoidal figures, interrupted with spherical grains, devoid of color and opaque. The highest-grade material is rosy white or yellowish white in color, soft, concentric, often brilliantly radiated, with a mam- millary or conchoidal surface. Red spots from iron and beautiful dendrites of manganese are not infrequent. The poorer qualities are milky white, vitreous, hard, and, though free from limestone, contain considerable silica. In the Caceres district the phosphorites occur not in veins, but rather in pockety masses in veins of quartz and dark-colored lime- stone, which are found cutting both the granite and slate. The following analyses from Dr. Penrose's paper show about the average composition of these phosphorites : LOGROSAN, BY PROFESSOR DAUBENY. Silica ^ i . 70 Protoxide of iron 3.15 Fluoride of lime 14.00 Phosphate of lime 81.15 CACERES, BY BOBIERRE AND FRIEDEL. Insoluble siliceous matter 21 .05 Water expelled at a red heat 3 .00 Tribasic phosphate of lime 72.10 Loss, iron oxides, etc 3 . 85 Portugal. Phosphorites occur in Silurian and Devonian rocks under similar conditions to those of Spain in Estremadura, Alemetjo, and Beira provinces, and which need, therefore, no further notice PHOSPHATES. 281 here. Stanier, 1 however, describes a variety found in pockety and short veinlike masses which are worthy of a passing notice. These occur not in schists and sedimentary rocks but in massive granites. They are found mainly in the superficial portions, where the granite has weathered away to a coarse sand, and in short gash-like veins and pockets of slight width and extent. The phosphatic material is described as of a milk-white color, opaque, and showing when broken open a palmately radiating structure, like hoarfrost upon a window pane. As a rule the masses when found are enveloped in a thin coating of kaolin-like material supposed to be derived by decomposition from the feldspar of the granites. They are mined only from open cuts and in the superficial more or less de- composed portions of the rock, to which they are believed to be mainly limited, having originated, as elsewhere indicated, through a segregation of the phosphatic material dissolved by meteoric waters from the surrounding granite and subsequently depositing it in preexisting fissures. The percentage of tricalcic phosphate is given as varying between 60 and 80 per cent. Italy. Phosphatic deposits consisting of coprolites, bones, etc., embedded in a porous Tertiary limestone, occur between Gallipoli and Otranto, Cape Leuca, west of the Gulf of Taranto, on the Italian coast. There are two beds having a thickness of 19 J and 31 J inches, respectively, and which have been traced for a distance of some 1 60 yards. Analyses show them to be of low grade, rarely carrying as high as 10 per cent P 2 O 5 . Tunis. Phosphatic nodules in the form of cylindrical coprolites and clustered aggregates have been found in Tertiary strata covering considerable areas in the region south of Tunis. The coprolite nodules are stated to carry as high as 70 per cent of calcium phos- phate, and the clustered aggregate some 52 per cent. Russia. Rich phosphate deposits of Cretaceous age occur in the governments of Smolensk, Orlow, Koursk, and Vorouez, between the rivers Dnieper and the Don in European Russia. The deposits lie mostly in a sandy marl, underlying white chalk and overlying green- 1 Les Phosphorites du Portugal, Annales de la Societe Geologique de Belgique, XVII, 1890, p. 223. 282 THE NON-METALLIC MINERALS. sands, which also carry beds of from 6 to 12 inches thickness of phos- phatic nodules. The nodules are dark, often nearly black in color, and are intermixed with gray, brown, and yellow sands. The depth of the beds below the surface is variable. Yermolow 1 divides the deposits into two groups, the first presenting the form of separate nodules, rounded or kidney-shaped, of variable size, and black, brown, gray, or green in color. The second is in form of an agglom- eration of large nodules cemented together into a sort of flag, which used to be quarried for road purposes. The nodules in this ag- glomerate are richer in phosphoric acid when most dense and of a deep-black color, the sandy varieties being comparatively poor. The cement carrying the nodules contains numerous fossil bones, shells, corals, etc., which are also phosphatic. The samples yield about 30 to 60 per cent phosphate of lime. Other deposits occur south of Saratov, on the Volga ; at Tambov and Spask, where the overlying rock is a greensand in place of the chalk; north of Moscow; east of Nijni Novgorod; at Kiev, on the Dnieper; Kamenetz, Podolsk, on the Dniester, and at Grodno, on the Niemen. Maltese Islands. 2 Nodular phosphates occur in Miocene beds on the islands of Malta, Gozo, and Comino, of the Maltese group in the Mediterranean Sea. The bed containing the nodules is in what is known as the Globigerina limestone, which underlies an upper coralline limestone, greensands, and blue clays, and overlies the lower coralline limestone. Upper and lower beds all carry phosphoric acid in small amounts. There are four seams of nodules, the first varying in different localities from 9 to 1 5 inches in thickness. The second is more constant in character, averaging some 2 feet in thickness and consisting of an aggregate of irregularly shaped nodules, intermixed with which are considerable quantities of the phosphatized remains of mollusks, corallines, echinoderms, crus- taceans, sharks, whales, etc., the whole being firmly bound together by an interstitial cement, composed of foraminiferal and other calcareous matter similar to that of which the overlying beds are made up. The third seam is the poorest of the lot and consists 1 Recherches sur les Gisements de Phosphate de Chaux Fossil en Russie. 2 J. H. Cooke, The Phosphate Beds of the Maltese Islands. Engineering and Min- ing Journal, LIV, 1892, p. 200. PHOSPHATES. 283 of two or more thin layers of nodules, none of which exceeds 3 inches in thickness. Between this and the fourth and lowest seam, which is the most important of all, is a bed of rock some 50 to 80 feet in thickness. The seam averages some 3^ feet in thickness. The nodules are of a dark-chocolate color embedded in a calcareous matrix, from which they are freed by calcination. The composi- tion of I, the nodules, and II, the average composition of nodules and interstitial cement, is given below, from analyses by Drs. Murray and Blake: Constituents. I. II. Sulphate of lime 2 26 I O7 Carbonate of lime 47.14 i.y/ 51.12 Phosphate of lime 38 34 3i 66 Alumina (Al O ) c 08 IO tJO Oxide of iron (Fe O ) Trace fl3 83 Residue 608 "p o bo 87 Total oo 80 IOO OO a. Silica. b. Moisture. Guano, soluble and leached. The largest and best-known deposits of unleached guanos are found on the mainland and small islands off the coasts of Peru and Bolivia, where abundant animal life and lack of rainfall have contributed to their formation and preservation. These deposits consist mainly of the evacuations of sea fowl and marine animals, such as flamingoes, divers, pen- guins, and sea lions. Mixed with them is naturally more or less bone and animal matter furnished by the dead bodies of both birds and mammals. The deposits vary indefinitely in extent and thick- ness, but have attained in places a depth of upward of 100 feet. As a rule they are more compact beneath than at the surface, but may be readily removed by pick and shovel. The first deposits to be worked are stated to have been those of the Chincha Islands, off the Peruvian coast. These were practically exhausted as early as 1872. Other islands which have been worked and completely if not entirely stripped are those of Macabi, Guanape, Ballestas, Lobos, Foca, Pabellon de Pica, Tortuga, and Huanillos. A mean of 21 analyses of Macabi Island guano, by Barral, as quoted by Penrose, 1 showed: 1 Bulletin No. 46 of the United States Geological Survey. 284 THE NON-METALLIC MINERALS. Nitrogen 10 . 90 Phosphates 27.60 Potash 2 to 3 Other analyses are given in the following table: Constituents. Angamos, Coast of Bolivia, White Guano. Bolivian. Los Patos. Island of Elide, Coast of California. Organic matter. 70.21 to 52.92 20.09 " J 4-38 24.36" 17.44 13.30 " 20.95 23.00 3.38 4.10 48.60 3 2 -45 5-92 7 .l8 34.81 27.37 to 34-50 1-34" 6.98 1.62 " 8.46 a28.oo " 31.00 Containing nitrogen. Equivalent in ammonia. . . Total phosphates Constituents. hot de Pe- dro-Bey, Coast of Cuba. Mexican Coast. Galapa- gos, Ecuador. Falkland Islands. Organic matter 6.16 0.28 0.34 48.52 13.05 to 18.00 0.21 " 3.45 0.26 " 4.19 8.00 " 25.00 17.35 to 28.68 0.56 " 2.26 0.68 " 2.74 021.46 " 25.62 Containing nitrogen 0.7 0.85 60.30 Equivalent in ammonia. . . Total phosphates a. Containing sometimes very considerable quantities of phosphates of alumina and the oxide of iron. Aside from on the islands, guano is found all along the coast of the Chilean province of Tarapaca, from Carmarones Bay to the mouth of the river Loa, there being scarcely a prominence or rock on the shore that does not contain some guano. According to the Journal of the Society of Chemical Industry, 1 the deposits have been known from a very early date. The aborigines of the valleys and gullies of Tarapaca, Mamina, Huatacondo, Camina, and Quisma were acquainted with the fertilizing qualities of guano, and conveyed it from the coast to their farms on the backs of llamas. The southern beds vary so much in aspect and color that it frequently requires an experienced eye to make them out. Many of the deposits are covered with immense layers of sand, while others are buried beneath a solid layer of conglomerate. Guano is also frequently found in the fissures and gullies which descend to the seashore. The richest and largest beds are at Pabellon de Pica, Punta de Lobos, Huanillos, and Chipana. 1 Volume VI, 1887, p. 228. PHOSPHATES. 285 Aside from the localities above mentioned, guano is found on the islands Itschabo, Possession, Pamora, and Halifax, off the Namagua coast of South Africa. The material is described as forming a grayish-brown powder, free from large lumps, and possessing a faint ammoniacal odor. It carries from 8 to 14 per cent of nitrogen and 8 to 12 per cent of phosphoric acid. 1 The West India Islands. 'Phosphates belonging to the class of leached guanos occur in considerable abundance on several of the islands of the West Indies group, the principal localities being Sombrero, Navassa, Turk, St. Martin, Aruba, Curacao, Orchillas, Arenas, Roncador, Swan, Cat or Guanahani, Redonda, the Pedro and Morant Keys, and the reefs of Los Monges and Aves in Mara- caibo Gulf. These, as would naturally be expected from their mode of origin, vary greatly, not merely in appearances, but in chemical composition as well. That of Sombrero is described 2 as occurring in two forms one a granular, porous, and friable mass of a white, pink, green, blue, or yellow color; the other as a dense, massive* and homogeneous deposit of a white or yellow color. Many bones occur. The phosphate carries from 70 to 75 per cent phosphate of lime. An analysis as given by Davies 3 is as follows : Moisture and water of combination . . . 8.92 Phosphoric acid 4 31 . 73 Lime :..... 45 . 69 Carbonic acid 5 5 . 99 Oxide of iron and alumina 7 . 07 Insoluble siliceous matter . . .60 100. oo The Navassa phosphate is described by D'Invilliers 6 as occurring (i) in the form of a gray phosphate confined to the lower levels of 1 Journal of the Society of Chemical Industry, I, 1882, p. 29. 2 R. F. Penrose, Bulletin No. 46 of the U. S. Geological Society. 8 D. C. Davies, Earthy and Other Minerals, p. 178. 4 Equal to tribasic phosphate of lime, 69.27 per cent. 6 Equal to carbonate of lime, 13.61 per cent. 6 Bulletin of the Geological Society of America, II, 1891, p. 75-89. 286 THE NON-METALLIC MINERALS. the island, and (2) a red variety occupying the oval flat of the in- terior. The gray is the better variety, as shown by the analyses below, though both are aluminous, and difficult of manipulation on that account. Both varieties occur in cavities and fissures in the surface of the hard gray, white, or blue limestone, of which the island is mainly composed. These cavities or pockets are rarely more than 4 or 5 yards wide on the surface, and frequently much smaller, and of depths varying from 5 to 25 feet. The deposits, so far as explored, are wholly superficial. Experimental shafts sunk to a depth of 250 feet have failed to bring to light any deeper lying beds. ANALYSIS OF GRAY NAVASSA PHOSPHATE. Water, at 100 C 2.33 Organic matter and water of combination. . 7 . 63 Lime 34.22 Magnesia .51 Sesquioxide of iron and alumina J 5 77 Potash and soda .86 Phosphoric acid 31 .34 Sulphuric acid .28 Chlorine .15 Carbonic acid i .84 Silica 4.53 Bone phosphate 68 .46 Bone phosphate (dry basis) 70 . 09 ANALYSIS OF RED NAVASSA PHOSPHATE. Loss on ignition 14-223 Lime 23 . 090 Magnesia Trace. Sesquioxide of iron 9 . 796 Alumina 18.425 Phosphoric acid 29 . 779 Sulphuric acid i . 160 Carbonic acid (by difference) 3 5 2 7 Bone phosphate 65 .037 PHOSPHATES. 287 The Aruba phosphate is described as a hard, massive variety of a white to dark-brown color. The underlying corals of this island are sometimes found phosphatized. An analysis given by Davies 1 is as follows; Per Cent. Moisture 8. 50 Water of combination 4.15 Phosphoric acid 2 28 .47 Lime 34 -7 Magnesia , .45 Carbonic acid 3 2 .30 Oxide of iron 4-49 Alumina 9 .48 Sulphuric acid * i .81 Insoluble siliceous matter 6.28 100.00 The Pedro Keys, Redonda, Alta Vela, and some others differ in carrying larger percentages of alumina and iron oxides, neces- sitating special methods of preparation. Deposits of leached guano of considerable extent have existed on several islands of the Polynesian Archipelago, in the Pacific Ocean, the better known being those of Bakers, Rowland, Jarvis, Malders, Birmie, Phoenix, and Enderbury islands. The deposits are described 4 as varying from 6 inches to several feet in thickness, of a whitish-brown or red color, pulverulent when dry, sometimes in the form of fine powder and again in coarse grains. Though closely compacted, the material can, as a rule, be readily removed by pick and shovel. The purest varieties are those lying on the un- altered coral limestones, of which the islands are mainly composed. Those lying upon gypsum have become contaminated with sulphate of lime. In places the deposits are covered with a thin crust due 1 D. C. Davies, Earthy and Other Minerals, p. 177. 2 Equal to tribasic phosphate of lime, 62.15 P er cen t 8 Equal to carbonate of lime, 5.22 per cent. 4 J. D. Hague, American Journal of Science, XXXIV, 1862, p. 224. 288 THE NON-METALLIC MINERALS. to the action of atmospheric agencies. On Jarvis Island a con- siderable share of the deposit is covered by material of this crust- like character. Such on analysis are found to contain less water and a corresponding higher percentage of lime and phosphoric acid than the loosely compacted material, being indeed, as shown by Mr. Hague, a nearly pure diphosphate of lime. The following analyses show the general character of these guanos from Bakers Island, No. I being freshly deposited and consisting of the dung of the frigate bird (Pelicanus aquilus). No. II is a light-colored variety from a deep part of the deposit, and No. Ill dark guano from a shallow part. ANALYSES OF GUANO. Constituents. I. II. III. ^Moisture expelled at 212 F 10 40 2 Q2 I 82 Loss by ignition ^688 8 T.2 8 50 Insoluble in HC1 (unconsumed by ignition) 0.78 v$* Lime 22 AI 4.2 74. 4.2 34 ^Magnesia i 46 2 S4 2 7? Sulphuric acid 2 ^6 I 3O "'/O I 24 Phosphoric acid 21 27 i.^u 3Q 70 4O 14 Carbonic acid, chlorine, and alkalies, undetermined. . 4-44 2.48 3.21 Total. IOO OO IOO OO IOO OO Soluble in water remaining after ignition 1 61 Bat Guano. The dry atmosphere of caves preserves indefinitely the fecal matter of bats and such other animals as may frequent them. Such under favorable conditions may accumulate in suf- ficient quantities to become of economic importance, being gathered and used as a fertilizer under the name of bat guano. The usual form of the entrances to caves is, however, such as to make the process of removal tedious and expensive. Bat guano is, as a rule, dark in color, of a glossy, almost muci- laginous appearance, and quite hard. Its composition is shown in the following analysis of a sample from the Wyandotte caves * in southern Indiana: Geology of Indiana, 1878, p. 163. PHOSPHATES. 289 Loss at red heat 44. 10 Organic matter 4-9 Ammonia 4.25 Silica 6.13 Alumina 14-3 Ferric oxide 1.20 Lime 7-95 Magnesia i . 1 1 Sulphuric acid 5.21 Carbonic acid 3-77 Phosphoric acid 1.21 Chloride of alkalies and loss 5 .82 100.00 According to the reports of the State geologist, the caves in the Silurian strata in Burnet County, Texas, are in many instances enormously rich in bat guano. Muntz and Marcano 1 have called attention to the extensive deposits of guano, sometimes amounting to millions of tons, in caves in Venezuela and other parts of South America. According to them the deposits consist not merely of the excreta of the birds and bats which frequent the caves, but also of the dead bodies of these and other animals. The excreta were found to consist almost wholly of the remains of insects. Through the agency of bacteria, nitrification takes place, whereby the organic nitrogen is converted into nitric acid, which combines with the lime from the bones or the carbonate of lime in the soils to form nitrates, as described on page 311. Uses. The phosphates of the classes thus far described are used wholly for fertilizer purposes. In their natural condition they exist in the form known to chemists as tribasic phosphates that is, a compound in which three atoms of a base mineral, usually calcium, are combined with one of phosphoric anhydride (P 2 O 8 ). Thus the common tribasic phosphate of lime has the formula (CaO) 3 P 2 O 5 =45.81 parts by weight P 2 O 5 and 54.19 CaO. Other 1 Comptes Rendus de PAcademie des Sciences, Paris, 1885, p. 65. 290 THE NON-METALLIC MINERALS. bases, as alumina, iron, or magnesia, may partially replace the lime, but the phosphate is always deteriorated thereby. This is particu- larly the case when aluminum and iron are the replacing constituents. Although when finely ground the tricalcic phosphates are of value for fertilizers, it is customary to first submit them to chemical treat- ment in order to render them more readily soluble. This treatment consists, as a rule, in converting them into a superphosphate by treatment with sulphuric acid, whereby a por- tion of the base becomes converted into sulphates and the anhydrous and insoluble tribasic phosphate into a hydrous and soluble mono- basic form of the formula CaO.(H 2 O) 2 .P 2 O 5 . There are other reactions than those above given, but the process is one too com- plicated for discussion here, and the reader is referred to especial treatises on the subject. BIBLIOGRAPHY. R. A. F. PENROSE, JR. Nature and Origin of Deposits of Phosphate of Lime. Bul- letin No. 46, U. S. Geological Survey, 1888. Gives a bibliography, up to date, of publication. The following have appeared since: W. H. ADAMS. List of Commercial Phosphates. Transactions of the American Institute of Mining Engineers, XVIII, 1889, p. 649. JOHN D. FROSSARD. About some Apatite Deposits of Ontario. Engineering and Mining Journal, VIII, 1889, p. 194. PAUL LEVY. Des phosphates de chaux. De leurs principaux gisements en France et a 1'etranger des gisements recemment decouvertes. Utilisation en agriculture; assimilation par les plants. Annales des Sciences Geologique, XX, 1889, p. 78. THEODOR DELMAR. Das Phosphoritlager von Steinbach und allgemeine Gesichts- punkte iiber Phosphorite. Vierteljahrschrift der Naturforschenden Gesellschaft in Zurich, 1890, p. 182. HENRI LASNE. Sur les Terrains phosphates des environs de Doullens. Etage Seno- nien et Terrains superposes. Bulletin de la Societe Geologique de France, XVIII, 1890, p. 441. Idem, XX, 1892, p. 211. ' Idem, XXII, 1894, p. 345. ALBERT R. LEDOUX. The Phosphate Beds of Florida. Engineering and Mining Journal, XLIX, 1890, p. 175. HJALMAR* LUNDBOHM. Apatitforekomster I Gellivare Malmberg och Kringliggande Trakt. Sveriges Geologiska Undersokning, ser. C, 1890, p. 48. X. STAINIER. Les depots phosphates des environs de Thuillies. Annales de la Societe Geologique Belgique, XVII, 1890, p. LXVI. PHOSPHATES. 291 X. STAINIER. Les Phosphorites du Portugal. Idem, p. 223. WALTER B. M. DAVIDSON. Suggestions as to the origin and deposition of Florida phosphates. Engineering and Mining Journal, LI, 1891, p. 628. EDWARD V. D'INVILLIERS. Phosphate Deposits of the Island of Navassa. Bulletin of the Geological Society of America, II, 1891, p. 75. N. DE MARCY. Remarques sur les Gites de Phosphate de Chaux de la Picardie. Bulletin de la Societe Geologique de France, XIX, 1891, p. 854. EUGENE A. SMITH. Phosphates and Marls of Alabama. Bulletin No. 2, Geological Survey of Alabama, 1892. W. DE L. BENEDICT. Mining, Washing, and Calcining South Carolina Land Phos- phate. Engineering and Mining Journal, LIII, 1892, p. 349. JOHN H. COOKE. The Phosphate Beds of the Maltese Islands. Engineering and Mining Journal, LIV, 1892, p. 200. WALTER B. M. DAVIDSON. The Present Formation of Phosphatic Concretions in Deep-sea Deposits. Engineering and Mining Journal, LIII, 1892, p. 499. D. C. DAVIES. Phosphate of Lime. Chaps. VII, VIII, IX, X, pp. 109-180, of A Treatise on Earthy and Other Minerals and Mining, 3d ed., revised by E. Henry Davies. London: Crosby, Lock wood & Son, 1892. HJALMAR LUNDBOHM. Apatitforekomster I Norrbottens Malmberg. Sveriges Geologiska Undersokung, ser. C, 1892, p. 38. N. A. PRATT. Florida Phosphates; The Origin of the Boulder Phosphates of the Withlacoochee River District. Engineering and Mining Journal, LIII, 1892, p. 380. FRANCIS WYATT. Phosphates of America. New York, 4th ed., 1892. W. P. BLAKE. Association of Apatite with Beds of Magnetite. Transactions American Institute Mining Engineers, XXI, 1893, p. 159. Contribution to the Early History of the Industry of Phosphate of Lime in the United States. . Idem, p. 157. A. GAUTIER. Sur des phosphates en roche d'origine animale et sur un nouveau de phosphorites. Comptes Rendus, CXVI, 1893, pp. 928 and 1022. A. GAUTIER. Sur la genese des phosphates naturels, et en Particulier de ceux qui ont emprunte leur phosphore aux etres organises. -Comptes Rendus, CXVI, 1893, p. 1271. J. GOSSELET. Note sur les gites du Phosphate de Chaux de Templeux-Bellicourt et de Buire. Societe Geologique du Nord, XXI, 1893, p. 2. - Note sur les gites de Phosphate de Chaux des environs de Fresnoy-le-Grand. Idem, p. 149. THOMAS M. CHATARD. Phosphate Chemistry as it concerns the Miner. Transactions of the American Institute Mining Engineers, XXI, 1893, p. 160. THE NON-METALLIC MINERALS. H. ELDRIDGE. A Preliminary Sketch of the Phosphates of Florida. Transactions of the American Institute Mining Engineers, XXI, 1893, p. 196. CHARLES HELSON. Notes sur la nature et le gisement du phosphate de chaux nature! dans les departments du Tarn-et-Garonne et du Tarn. Societe Geologique du Nord, XXI, 1893, p. 246. WALTER B. M. DAVIDSON. Notes on the Geological Origin of Phosphate of Lime in the United States and Canada. Transactions of the American Institute Mining Engineers, XXI, 1893, p. 139, WILLIAM B. PHILLIPS. A List of Minerals containing at least one per cent of Phos- phoric Acid. Transactions of the American Institute Mining Engineers, XXI, 1893, p. 188. H. B. SMALL. The Phosphate Mines of Canada. Transactions of the American Institute Mining Engineers, XXI, 1893, p. 774. JOHN STEWART. Laurentian Low-grade Phosphate Ores. Transactions of the American Institute Mining Engineers, XXI, 1893, p. 176. CARROLL D. WRIGHT. The Phosphate Industry of the United States. Sixth Special Report of the Commissioner of Labor, 1893. Washington: Gov- ernment Printing Office. M. BLAYAC. Description Geologique de la Region des Phosphates du dyr et du Kouif Pres Tebessa. Annales des Mines, VI, 1894, p. 319. Note sur les Lambeaux Suessoniens a Phosphate de Chaux de Bordj Redir et du Djebel Mzeita. Idem, p. 331. EUGENE A. SMITH. The Phosphates and Marls of the State. Report on the Geology of the Costal Plain of Alabama, 1894, pp. 449-525. A. GAUTIER. Sur un Gisement de Phosphates de Chaux ct d'Alumine contenant des especes rares ou nouvelles et sur la Genese des Phosphates et Nitres naturels. Annales des Mines, V, 1894, p. 5. THOMAS C. MEADOWS and LYTLE BROWN. The Phosphates of Tennessee. Engineering and Mining Journal, LVIII, 1894, p. 365. WILLIAM B. PHILLIPS. The Phosphate Rocks of Tennessee. Engineering and Mining Journal, LVII, 1894, p. 417. DAVID LEV AT. Etude sur 1'industrie des Phosphates et Superphosphates. (Tunisie- Floride-scories basiques.) Annales des Mines, VII, 1895, p. 135. J. M. SAFFORD. Tennessee Phosphate Rocks. Report of the Commissioner of Agriculture, Nashville, Tennessee, 1895, p. 16. CHARLES WILLARD HAYES. The Tennessee Phosphates. Extract from the Seventeenth Annual Report of the U. S. Geological Survey, 1895-96. Pt. 2, Economic Geology and Hydrography. Washington: Govern- ment Printing Office, 1896. Also Twenty-first Annual Report, Part III, 1899- 1900. M. BADOUSEAU. Sur les gisements de chaux phosphates de 1'Estremadure. Bulletin de la Societe Centrale Agriculture de France, XXXVIII. X. STAINER. Bibliographic Generale des Gisements des Phosphates. Annales des Mines de Belgique, VII, 1902 et seq. PHOSPHATES. 293 2. MONAZITE. Composition, a phosphate of cerium metals of the general formula (Ce, La, Di) PO 4 . Actual analyses as given by Dana yielded results- as below: Constituents. I. II. Phosphoric anhydride (P O ) 29.28 3i-38 [ 30.88 2 7-55 29.20 26.26 3-82 I-*3 1.86 9-57 0.69 0.52 Cerium sesquioxi'de (Ce a O 3 ) Lanthanum sesquioxide (La 2 O 3 ) Didymium sesquioxide (Di 2 O 3 ) Silica (SiO ) . 1.40 6.49 Thoria (ThO ) . Lime (CaO) Ignition . . . . O.2O Total 99- 6 3 100.60 I. Burke County, North Carolina. II. Arendal, Norway. The crystals are commonly minute, often flattened; not un- commonly in form of small cruciform twins. The mineral also occurs in coarse masses yielding angular fragments. Hardness, 5 to 5.5; specific gravity, 4.9 to 5.3. Color, hyacinth-red to brown and yellowish, subtransparent to translucent. Localities and mode o] occurrence. The common form of oc- currence of the mineral is that of minute crystals or crystalline granules disseminated throughout the mass of gneissoid rocks. Owing to their small size they have been very generally overlooked, and it is only where, through the decomposition of the inclosing rock and the concentration of these and the accompanying heavy minerals as magnetite, garnet, etc. in the form of sand, that it becomes sufficiently conspicuous to be evident. Prof. O. Derby was the first to point out the widespread occurrence of the mineral as a rock constituent, he having obtained it in numerous and hitherto unsuspected localities by washing the debris from decomposed gneisses of Brazil. Although widespread as a rock constituent and of interest from a mineralogical and petrographical standpoint, only the localities mentioned below have thus far yielded the mineral in commercial quantities. 294 THE NON-METALLIC MINERALS. North Carolina. The mineral is found in considerable quantities in the form of small brown, greenish, or yellow-brown granules, often rounded by water action, in the gold-bearing sands of Ruther- ford, Polk, Alexander, Burke, and McDowell counties, and also in the neighborhood of Crowders Mountain, Gaston County, and at Todds Branch, in Mecklenburg County, where it occurs associated with zircons and an occasional diamond. Fine crystals over an inch in length have been found in Mitchell County, and large cleav- able masses, sometimes 3 or 4 inches across and of a yellowish- brown color, at Mars Hill, in Madison County. According to Mr. H. B. Nitze the commercially economical deposits of monazite are those occurring in the placer sands of the streams and adjoining bottoms and in the beach sands along the seashore. The geographical areas over which such workable deposits have been found up to the present time are quite limited in number and extent. In the United States the placer deposits of North and South Carolina stand alone. This area includes between 1,600 and 2,000 square miles, situated in Burke, McDowell, Rutherford, Cleveland, and Polk counties, North Carolina, and the northern part of Spartanburg County, South Carolina. The principal deposits of this region are found along the waters of Silver, South Muddy, and North Muddy creeks, and Henrys and Jacobs Forks of the Catawba River in McDowell and Burke counties; the Second Broad River in McDowell and Rutherford counties; and the First Broad River in Rutherford and Cleveland counties, North Carolina, and Spartanburg County, South Carolina. These streams have their sources in the South Mountains, an eastern outlier of the Blue Ridge. The country rock is granitic biotite gneiss and dioritic hornblende gneiss, intersected nearly at right angles to the schistosity by a parallel system of small auriferous quartz veins, striking about N. 70 E. and dipping steeply to the N. W. Most of the stream deposits of this region have been worked for placer gold. The existence of monazite in commercial quantities here was first established by Mr. W. E. Hidden in 1879. The thickness of these stream gravel deposits is from i to 2 feet, and the width of the moun- tain streams in which they occur is seldom over 12 feet. The per- centage of monazite in the original sand is very variable, from an PHOSPHATES. 295 infinitesimal quantity up to i or 2 per cent. The deposits are naturally richer near the headwaters of the streams. From these deposits amounts varying from 30,000 pounds to 1,573,000 pounds have been washed annually since systematic mining began in 1893. In 1901 the amount was 748,736 pounds, valued at $59,262. The miner usually receives from 3^ to 5 cents per pound. Brazil. As above noted, the original source of the Brazilian monazite were gneisses from which the mineral has been liberated by decomposition. The particular localities examined by Professor Derby are in the provinces of Minas Geraes, Rio de Janeiro, and Sao Paulo. The most extensive accumulation thus far reported is in the form of considerable patches on the sea beach near the little town of Alcobaca in the southern part of the province of Bahia, though it has been also found on other sea beaches and in river sands. Nitze states: 1 "Sacks filled with this sand were shipped to New York in 1885, the deposit having been taken for tin ore. Its true character was, however, soon recognized, and since then a number of tons have been shipped in the natural state, without any further concentra- tion or treatment, as ballast, mainly to the European markets. It is reported to contain 3 to 4 per cent thoria. . . . Monazite has also been found in the gold and diamond placers of the provinces of Bahia (Salabro and Caravellas), Minas Geraes (Diamantia), Rio de Janeiro, and Sao Paulo. It has been found in the river sands of Buenos Ayres, Argentine Republic, and also in the gold placers of Rio Chico, at Antioquia, in the United States of Colombia." Russia. "In the Ural Mountains of Russia monazite is found in the Bakakui placers of the Sanarka River. The placer gold mines of Siberia are reported to be rich in monazite, which is rafted down the Lena and the Yenesei rivers to the Arctic Ocean, and thence to European ports. Norway. "Economic deposits of monazite are also reported to exist in the pegmatic dikes of Southern Norway. It is picked by the miners while sorting feldspar at the mines. It is not known 1 Sixteenth Annual Report U. S. Geological Survey, 1894-95, pt. 4, p. 685. 296 THE NON-METALLIC MINERALS. to exist in placer deposits. The annual output is stated to be not more than i ton, which is shipped mainly to Germany. Methods of extraction. " In the Carolinas the monazite is won by washing the sand and gravel in sluice boxes exactly after the manner that placer gold is worked." The sluice boxes are about 8 feet long by 20 inches wide by 20 inches deep. Two men work at a box, the one charging the gravel on a perforated plate fixed in the upper * end of the box, the other one working the contents up and down with a gravel fork or perforated shovel in order to float off the lighter sands. These boxes are cleaned out at the end of the day's work, the washed and concentrated monazite being collected and dried. Magnetite, if present, is eliminated from the dried sand by treatment with a large magnet. Many of the heavy minerals, such as zircon, menaccanite, rutile, brookite, corundum, garnet, etc., can not be completely eliminated. The commercially prepared sand, therefore, after washing thoroughly and treating with a magnet, is not pure monazite. A cleaned sand containing from 65 to 70 per cent mona- zite is considered of good quality. From 20 to 35 pounds of cleaned monazite sand per hand, that is, from 40 to 70 pounds to the box, is considered a good day's work. The price of labor is 75 cents per day. "But very few regular mining operations are carried on in the region. As a rule each farmer mines his own monazite deposit and sells the product to local buyers, often at some country store in exchange for merchandise. "At the present time the monazite in the stream beds has been practically exhausted, with few exceptions, and the majority of the workings are in the gravel -deposits of the adjoining bottoms. These deposits are mined by sinking pits about 8 feet square to the bed rock and raising the gravel by hand labor to a sluice box at the mouth of the pit. The overlay is thrown away excepting in cases where it contains any sandy or gritty material. The pits are carried forward in parallel lines, separated 'by narrow belts of trailing dumps, similar to the methods pursued in placer gold mining. " At the Blanton and Lattimore mines on Hickory Creek, 2 miles northeast of Shelby, Cleveland County, North Carolina, the bottom PHOSPHATES. 297 is 300 to 400 feet wide, and has been partially worked for a distance of one-fourth of a mile along the creek. The overlay is from 3 to 4 feet and the gravel bed from i to 2 feet thick. The methods of mining and cleaning are much more systematic in Spartanburg County, South Carolina, than in North Carolina regions. Although the raw material contains on an average fully as much garnet, rutile, titanic iron ore, etc., as that in the North Carolina mines, a much better finished product is obtained, and more economically, by making several grades. Two boxes are used in washing the gravel, one below the other. The gravel is charged on a perforated plate at the head of the upper box, and the clean-up from this box is so thoroughly washed as to give a high-grade sand, often up to 85 per cent pure. The tailings discharge directly into the lower box, where they are rewashed, giving a second-grade sand. At times the material passes through as many as five washing treatments in the sluice boxes. Even after these grades are obtained as clear as possible by washing, the material, after being thoroughly dried, is further cleaned by pouring from a cup, or a small spout in a bin, in a fine, steady stream from a height of about 4 feet, on a level platform; the lighter quartz and black sand with the fine-grained monazite (tailings) falls on the periphery of the conical pile and is constantly brushed aside with hand brushes; these tailings are afterwards rewashed. Instead of pouring and brushing, the material is sometimes treated in a winnowing machine similar to that used in separating chaff from wheat. "Although the best grade of sand is as high as 85 per cent pure, its quantitative proportion is small as compared with the second and other inferior grades, and there is always considerable loss of monazite in the various tailings. It is impossible to conduct this washing process without loss of monazite, and equally impossible to make a perfect separation of the garnet, rutile, titanic iron ore, etc., even in the best grades. The additional cost of such rewashing and rehandling must also be taken into consideration. "If the material washed contains gold, the same will be collected with the monazite in concentrating. It may frequently pay to separate it, which can easily be accomplished by treating the whole mass over again in a rifHe box with quicksilver. 298 THE NON-METALLIC MINERALS. "It has been shown that the monazite occurs as an accessory constituent of the country rock, and that the latter is decomposed to considerable depths, sometimes as much as 100 feet. On account of the minute percentage of monazite in the mother rock, it is usually impracticable to economically work the same a in place, by such a process as hydraulicking and sluicing, for instance. However, even hillside mining has been resorted to. Such is the case at the Phifer mine, in Cleveland County, North Carolina, 2 miles north- east of Shelby. The country rock is a coarse mica (muscovite and biotite) gneiss, and the small monazite crystals may at times be distinctly seen, unaided by a magnifying glass, in this rock. It is very little decomposed and still quite hard, and the material that is mined for monazite is the overlying soil and subsoil, which is from 4 to 6 feet thick. This is loaded on wheelbarrows and transported to the sluice boxes below the water race. The yield is fairly good, and the product very clean, though the cost of working . . . must be considerably in excess of that of bottom mining. Where the rock contains sufficient gold, as it sometimes does, to be operated as a gold mine, there is no reason why the monazite can not be saved as a valuable by-product." * Uses. The rare elements cerium, zirconium, thorium, yttrium, lanthanum, etc., which .are as a rule associated with each other in the minerals cerite, zircon, monazite, samarskite, etc., as de- scribed,, find their commercial use not in the form of metals, but as oxides only; and it is only since the introduction of the Welsbach incandescent system of lighting that their use in this form has assumed any commercial importance. This Welsbach light consists of a cap or hood to gas or other burners, to increase their illuminating powers. The cap is made of cotton or other suitable, material, impregnated with the oxides in proportions 60 per cent zirconia, 20 per cent yttria, and 20 per cent lanthanum. The fabric is strengthened and supported with fine platinum wire and suspended in the flame. On igniting in the flame the fabric is quickly reduced to ash, the cotton being burnt away and the earthy matter still retaining the form of a cap or hood. 2 1 Sixteenth Annual Report U. S. Geological Survey, 1894-95, Ft. 4, pp. 686-687. 2 Journal of the Society of Chemical Industry, V, 1886, p. 522. VANADATES. 299 The drawback to the use of these oxides has been, it is said, 1 the great difficulty in obtaining them in a pure condition. Several methods have been used, but usually with poor results, especially when the mineral contains iron. The cerium oxalate is used in pharmacy. The demand for the minerals of this group being so limited, there is no regular market price. The Mineral Industry for 1893 quotes zircon at 10 cents a pound, monazite, 25 cents, and samarskite, 50 cents. In 1901 monazite from North Carolina was quoted at 8 cents per pound, of which the original mines received from 3^ cents to 5 cents per pound, according to the purity of the material. It is stated that i ton of zircon will yield sufficient zirconia for half a million Welsbach burners. BIBLIOGRAPHY. See paper on Monazite, by H. B. C. Nitze, in Mineral Resources of the United States, Part 4, of the Sixteenth Annual Report U. S. Geological Survey, 1894-95, pp. 667-693. This contains a very satisfactory bibliography down to date of publi- cation. Also see Les Terres Rares Mineralogie-Properties Analyse, by P. Truchot. Carre et Naud. Paris, 1898. 3. VANADINITE. This is a vanadinate and chloride of lead of the formula (PbCl) Pb 4 V 3 O 12 , = vanadium pentoxide, 19.4 per cent; lead protoxide, 78.7 per cent; chlorine, 2.5. In nature often more or less impure through the presence of arsenic and traces of iron, manganese, zinc, and lime. Color deep red to brown and straw-yellow, resinous luster; translucent to opaque. Hardness, 2.75 to 3. Gravity, 6.66 to 7.23. When a drop of nitric acid is applied to a particle of a crystal there is soon formed a yellow coating of vanadic oxide. This reaction is quite characteristic and furnishes an easy and convenient means of determination. Localities and mode of occurrence. Occurs in prismatic crystals with smooth faces and sharp edges; crystals sometimes cavernous at the top. Also common in parallel grouped and rounded forms and globular incrustations. Dana gives the following relative to the known localities: "This mineral was first discovered at Zimapan in Mexico, by Del Rio. Later obtained among some of the old workings at Wan- 1 Mineral Resources of the United States, 1885, p. 393. THE NON-METALLIC MINERALS. lockhead in Dumfriesshire, where it occurs in small globular masses on calamine, and also in small hexagonal crystals; also at Berezov in the Ural, with pyromorphite ; and near Kappel in Carinthia, in crystals ; at Undenas, Bolet, Sweden; in the Sierra de Cordoba, Argentine Republic; South Africa. "In the United States it occurs spar- ingly with wulfenite and pyromorphite as a coating on limestone, near Sing Sing, New York. In Arizona it is found at the Ham- FIG. 24. Vanadinite burg, Melissa, and other mines in Yuma County, in brilliant deep-red crystals; Vul- ture, Phoenix, and other mines in Maricopa County; at the Black Prince mine; also the Mammoth gold mine, near Oracle, Pinal County, and in brown barrel-shaped crystals in the Humbug district, Yavapai County. In New Mexico it is found at Lake Valley, Sierra County (endlichite) ; and the Mimbres mines near Georgetown." The characteristic mode of occurrence at the Mimbres mines, above noted, is associated with descloizite in the form of small hopper-shaped crystals and drusy or botryoidal and globular masses coating the siliceous residues of the limestone in the irregular cavities with which the stone abounds. The color of these coatings varies from beautiful ruby red to light ocherous yellow. The mineral is here nearly always associated with descloizites as noted below. Uses. See under Descloizite. 4. DESCLOIZITE. This is a vanadinate of lead and zinc of the formula 4(PbZn)O. V 2 O 5 ,H 2 O, = vanadium pentoxide, 22.7 per cent; lead protoxide, 55.4 per cent; zinc oxide, 19.7 per cent; water, 2.2 per cent. The published analyses show also small amounts of arsenic, copper, iron, manganese, and phosphorus. Color, red to brown; luster, greasy; no cleavage; fracture small conchoidal to uneven. Occurs in small pris- matic or pyramidal crystals and in fibrous, mammillated or massive forms. Often associated with and pseudomorphous after vanadinite. Localities and mode oj occurrence. Dana gives the following relative to occurrence: l/ANADATES. 3 O1 "Occurs in small crystals, i to 2 millimeters thick, clustered on a siliceous and ferruginous gangue from South America, at the Venus Mine and other points in the Sierra de Cordoba, Argentine Republic, associated with acicular green pyromorphite, vanadinite, etc. At Kappel, in Carinthia, in small clove-brown rhombic octa- hedrons. ******* "Sparingly at the Wheatley Mine, Phcenixville, Pennsylvania, as a thin crystalline crust on wulfenite, quartz, and a ferruginous clay. Abundant at the Sierra Grande Mine, Lake Valley, Sierra County, New Mexico, in red to nearly black crystals, pyramidal and prismatic in habit, associated with vanadinite, iodryite, etc.; at the Mimbres and other mines, near Georgetown, New Mexico, in stalactitic crystalline aggregates. In Arizona near Tombstone, in Yavapai County, in brownish olive-green crystals; at the Mam- moth Gold Mine, near Oracle, Final County, in orange-red to brownish red crystals with vanadinite and wulfenite." A vanadinite, probably identical with descloizite, occurs at the Mayflower Mine, Bald Mountain district, in Beaverhead County, Montana; it is in an impure earthy form of a dull yellow to pale orange color. (See further under Carnotite, p. 322.) Vanadium is also found in small quantities in certain Swedish iron ores; in the cupriferous schists of Mansfeld, Saxony; in cupri- ferous sands of Cheshire, England, and Perm, Russia; in coals from various localities; in beauxite and in clay near Paris. As stated by Fuchs and -De Launay, 1 vanadium has been shown to exist in extremely small proportions in primordial rocks, from which it became concentrated in the clays on their breaking up. Certain oolitic iron ores (limonites) at Mafenay, Saone et Loire, France, contain the substance in such proportions that the slag from their smelting have become commercial sources of supply, some 60,000 kilograms of vanadic acid being manufactured annually from them. The following referring to the occurrence and value of vanadinates in the United States is of sufficient interest to bear reproduction here: 1 Traite des Gites Mineraux, II, p. 95. 302 THE NON-METALLIC MINERALS. "The lead vanadates are frequently found in association with lead ores, as, for instance, in the deposits at Leadville, whence some very handsome specimens were formerly obtained. The most important occurrence of lead vanadates in the United States, however, is probably in Arizona, where it has been reported in the ores of several mines, among others those of the Castle Dome district, the Crowned King mine in the Bradshaw Mountains, and the Mam- moth gold mines at Mammoth, in Final County. The last-men- tioned mines are probably the only ones in the United States from which vanadium minerals have been won on an industrial scale. The vanadium minerals, of which nearly all the known varieties occurred, the dechenite and descloizite predominating, were found in the upper levels of the mine, forming about i per cent of the ore on the average, though within limited areas they formed from 3 to 4 per cent. In the lower levels they occurred less abundantly, only an occasional pocket and a small quantity of disseminated crystals being found. The red crystals, according to an analysis by the late Dr. F. A. Genth, contained chlorine, 2.43 per cent; lead, 7.08 per cent; lead oxide, 69.98 per cent; ferric oxide, 0.48 per cent; vanadic acid, 17.15 per cent; arsenic acid, 3.06 percent, and phosphoric acid, 0.29 per cent. In milling the ore (gold) the vanadium minerals collected in riffles, placed about 18 inches apart in the sluices. The material thus obtained was worked over by hand in a sort of buddle, and the resulting concentrates were sold to the Kalion Chemical Company, of Gray's Ferry Road, Phila- delphia. The total quantity of concentrates obtained in this manner did not exceed 6 tons. An average sample of the lot, analyzed by Dr. Genth, gave the following results: Vanadic acid, 15.40 per cent; molybdic acid, 3.35 per cent; arsenic acid, 1.50 per cent; carbonic acid, 0.90 per cent; chlorine, 0.48 per cent; oxide of lead, 56.80 per cent; oxide of zinc, 10.70 per cent; oxide of copper, 0.95 per cent; oxide of iron, 0.35 per cent; soluble silica, 0.60 per cent; insoluble matter, 5.29 per cent. The value of the gold and silver contents of the concentrates was about $140 per ton. The price realized on this first lot was 12.5 cents per pound, or $250 per ton, on board the cars at Tucson." "The vanadic salts manufactured from this lot of concentrates Y AN A DATES. 303 were said to have been the first produced on a commercial scale in the United States, and owing to the limited market for the same the price dropped over 50 per cent. "Frue vanners were then introduced into the mill, and the product obtained from them, amounting to about i ton per 100 tons of ore crushed, contained from 5 to 6 per cent vanadic acid and $40 to $80 per ton in gold and silver. The Kalion Chemical Com- pany offered to buy this product according to the following sliding scale : With the market price of ammonium vanadate $5 per pound, $100 per ton for the concentrates; vanadate of ammonium $4.50 per pound, concentrates $92 ; vanadate of ammonium $4 per pound, concentrates $82; vanadate of ammonium $3.50 per pound, con- centrates $72; vanadate of ammonium $3 per pound, concentrates $64. Only a few tons of these concentrates were shipped to Phila- delphia, the remainder being sold to the Denver smelters for their gold, silver, and lead value." 1 The name roscoe ite has been given to a clove-brown to green- ish, micacious mineral occurring in minute scales, stellate or fan- shaped forms, and of a somewhat doubtful chemical formula. It may be mentioned here as a possible source of vanadium salts al- though from a chemical and minerological standpoint- it should have been considered in connection with the mineral on p. 163. On the next page are given the results of two analyses from a recent paper by W. F. Hillebrand (i) being of material from Placerville, Colorado, and (2) from Eldorado County, California. Occurrence. The material has been reported as filling cavities in quartz at the Granite Creek gold mines near Coloma, El Dorado County, California, and in the Magnolia district of Colorado. More recently deposits of some considerable economic importance have been found near Placerville in San Miguel County, in the last-named State. The roscoelite is described 2 as occurring as an impregna- tion in the lower bed of what is known as the La Plata sandstone (Jurassic). The beds at this point are nearly horizontal, the por- tion carrying the roscoelite occurring in a nearly continuous band approximately parallel to the bedding planes and varying in thick- 'The Mineral Industry, II, 1893, p. 577. 2 F. L. Ransome, American Journal of Science, X, August, 1900. 34 THE NON-METALLIC MINERALS. ness from a few inches up to 5 or 6 feet, the vanadiferous portion being readily distinguished from the prevailing light-buff sand- stone by the greenish tint imparted by the roscoelite. The vanadif- erous zone is, however, quite irregular, the roscoelite sometimes constituting 20 per cent of the mass of the sandstone and from this fading out to nothing. It is often associated with Carnotite (see p. 322). ANALYSES OF ROSCOELITE, A VANADIUM MICA. Constituent. Vanadium Mica frrom Placerville, Colo. Roscoelite from Eldorado County, Cali- fornia. SiO 46.06 45- 1 ? .78 24.01 n-54 (FeO) i. 60 TiO V O 3 12.84 22-55 73 .44 Al O , Fe 0, cab. 3 ::::::::::: BaO I.3C MffO . .92 8.84 .22 1.98 51 3.56 1.64 10.37 Trace. 0.40 M7 4.12 K O NajO H O at 105 HO at ICK 300 H O above 300 IOO.OO 99.80 a. At 100. b. At 180. c. Above 180. Uses. The uses thus far developed for these minerals are as a source for vanadium salts used as a pigment for porcelain and in the manufacture of ferro vanadium alloys to be used in steel- making. Vanadate of ammonium and vanadic oxide are used in the manu- facture of ink and in textile dyeing and printing, imparting intense black colors with a slight greenish cast. Vanadium oxide obtained from the slags of the Creusol steel works in France to the amount of 165,000 pounds annually is utilized as a mordant in dyeing. When used in steel the vanadium is stated to very greatly increase the tensile strength and elastic limit, in the same manner as do chromium and nickel. A larger supply, it is thought, would result in its use in armor plate, projectiles, and bronzes. 6. AMBLYGONITE. This is a fluo-phosphate of aluminum and lithium, of the formula yANADATES. 305 Li(AlF)PO 4 . Analysis of a sample from Paris, Maine, as given by Dana, shows: Phosphoric acid, 48.31 per cent; alumina, 33.68 per cent; lithia, 9.82 per cent; soda, 0.34 per cent; potash. 0.03 per cent; water, 4.89 per cent; fluorine, 4.82 per cent. Hardness, 6', specific gravity, 3.01 to 3.09. Luster vitreous to greasy, color white to pale greenish, bluish, yellowish, to brownish; streak white. On casual inspection the mineral somewhat resembles potash feld- spar (orthoclase), but when finely pulverized is soluble in sulphuric acid, and less readily so in hydrochloric acid. Before the blowpipe the mineral gives the characteristic lithia red color to the flame. Mode of occurrence. Amblygonite occurs in the form of coarse crystals, or compact and columnar forms in pegmatic veins asso- ciated with lepidolite, tourmaline, and other minerals so charac- teristic of this class of veins. In the United States it occurs at Hebron; Mount Mica, in Paris; Auburn and Peru, Maine, at the latter place associated with spodumene, petalite, and lepidolite. In Saxony the mineral is found at Chursdorf and Arnsdorf, near Penig, and near Geier. Also found at Arendal, Norway, and at Montebras and Creuze, France. Uses. Since 1886 the mineral has been utilized as a source of lithia salts, in place of the lithia mica. The chief commercial source is at present Montebras, France, where it occurs in a coarse granitic vein yielding also cassiter^e and kaolin in commercial quantities. (See also Spodumene, p. 196). 7. TRIPHYLITE AND LITHIOPHILITE. These are names given to phosphates of iron, manganese, and lithium, and which pass into one another by insensible gradations through variations in the proportional amounts of manganese pro- toxide, the triphylite containing from iu to 20 per cent of this oxide, while the Jithiophilite contains twice that amount. The compara- tive composition of extreme types is shown below: Name. P 2 6 , FeO. MnO. Li 2 0. Na 2 O. H 2 O Triphylite A<2 jg 26 21 896 8 is o 87 I^ithiophilitf. 4.4.. 67 4. O2 4.0 86 8 63 o 82 306 THE NON-METALLIC MINERALS. Triphylite is a gray to blue-gray mineral in crystals and coarsely cleavable masses of a hardness of 4.5 to 5 of Dana's scale, and specific gravity of 3.42 to 3.56. Lithiophilite differs mainly in color aside from composition as above noted being of a pink to clove-brown hue. Both minerals may undergo a darkening in color, becoming almost black through a higher oxidation and hydration of the manganese protoxide. This feature is best shown in the lithiophilite from Branchville, Con- necticut. Occurrence. These minerals occur chiefly in granitic veins, associated with spodumene and other lithia bearing minerals, as at the localities above mentioned. Peru, Hebron, and Norway, Maine; Keityo, Finland, etc They have as yet been put to no practical use. IX. NITRATES. There are three compounds of nitric acid and a base occurring in nature in such quantities and of sufficient economic importance to merit attention here. These are (i) the true niter or potassium nitrate (KNO 3 ), (2) soda niter or sodium nitrate (NaNO 3 ), and (3) nitrocalcite, a calcium nitrate (CaN 2 O 6 ). All are readily soluble in water, and hence found in any quantity only in arid regions or where protected, as in the dry parts of caves. I. NITER, POTASSIUM NITRATE. Composition. KNO 3 , = nitric anhydride (NO 2 ), 53.5 per cent; potash (K 2 O), 46.5 per cent. Hardness, 2; specific gravity, 2.1; color, white, subtransparent. Readily soluble in water. Taste, saline and cooling. Deflagrates vividly when thrown on burning coals and colors the flame violet. The mineral occurs in nature mainly in the form of acicular crystals and efflorescences on the surface or walls of rocks and scattered in the loose soil of limestone caves and similar dry and protected places. It is also found in certain soils of tropical countries, as noted later under origin (p. 311). In the United States it has been found in caves of the Southern States, as those of Madison County, Ken- NITRATES. 3 7 tucky, but never as yet in commercial qualities. The chief com- mercial source of the salt has been the artificial nitrairies of France, Germany, Sweden, and other European countries. It is also pre- pared artificially from soda niter. 2. SODA NITER. Nitrate of sodium, NaNO 3 , = nitric anhydride (NO 2 ), 63.5 per cent; soda (N 2 O), 36.5 per cent. This in its pure state is a white or colorless salt, but 'in nature brown or bright lemon-yellow, of a slight saline taste, but with a peculiar cooling sensation when placed upon the tongue. It is by far the most common of the nitrates, and indeed the only one of the natural salts of any great commercial value, owing to the comparative rarity of the others. Though found to a slight extent in caves and protected places, the commercial supply is drawn almost wholly from the desert regions of the Pacific coast of South America and particularly from Chile, the chief deposits being found in the provinces of Tarapaca and Antofagasta. According to the Journal of the Society of Chemical Industry 1 "the total area of the province of Tarapaca is 16,789^ square miles, and it is divided naturally into five distinct and well-defined zones. The first of these zones commences on the shores of the Pacific and has an average width, west to east, of 18 miles. It is formed, in the first place, of the beach; and, in the second, of the coast range, which attains an altitude varying from 1,125 to 5>8oo feet above the sea level. This zone may be denominated the guano and mining zone. . . . This belt as it advances eastward becomes more and more depressed and terminates in a series of pampas (open plains), having an elevation of 3,500 to 3,800 feet above the sea level. Nearly all these pampas contain vast beds of salts, sul- phate of soda, and sulphate of lime. They are known locally by the name of 'salares.' In some parts of the desert of Atacama the beds of nitrate of soda are found under these salares deposits, but in Tarapaca the caliche (nitrate earth) is found only under a bed of conglomerate known as 'costra.' . . . "The second zone the nitrate zone commences on the edge of the Camarones Gully and extends southward to the desert of 1 Volume VI, 1887, pp. 228, 229. 3 8 THE NON-METALLIC MINERALS. Atacama. Up to 1858 it was believed that the nitrate beds did not extend southward beyond the Loa Gully, but in that year beds were discovered in what was then the Bolivian littoral. Explorations which were effected in 1872 proved that the nitrate beds extended northward beyond the Camarones Gully and that they reached as far as the Chaca Gully and even as far as the Azapa Valley, in the province of Alrica. . . . The quantity and quality of the caliche varies very considerably in different parts of the zone, but the dimensions of the nitrate area may be set down at 120 geo- graphical miles in length north to south, and 2 geographical miles in width east to west. It is estimated that the beds contain the enormous quantity of 1,980,630,502 quintals of niter, and it is stated that with the present export duty, which is equal to 27 pence per quintal, the deposits will yield a revenue of ^230,809,474. " It is elsewhere stated that the point on the slope of the mountains where the deposits of caliche are found is some 500 or 600 feet higher than the valley, but that the material diminishes in quantity and richness as the valley is approached and disappears entirely at the bottom. An examination of the workings of these beds discloses the follow- ing conditions: (1) That the surface to the depth of 8 or 10 inches is covered with a layer of fine, loose sand. (2) That underneath the sand is a conglomerate of amorphous porphyry, feldspar, chloride of sodium, magnesia, gypsum, etc., cemented by the sulphate of lime into a hard, compact mass to a depth of 6 to 10 feet, called the a costra" or crust. (3) That below this crust the caliche, or impure nitrate, is found, presenting to the view a variety of colors yellowish white, orange, bluish gray, etc. The nitrate deposit is quarried by blasting with a coarse-grained powder, of which as much as 150 pounds are sometimes used at a single blast. Neither dynamite nor nitroglycerin is used, as it would shatter and pulverize the salt so as to occasion a serious loss. After being brought to the surface the caliche is carefully assorted by experts, broken into pieces double the size of an orange, and carted to the refinery establishment, situated on the pampas or on NITRATES. 39 the seacoast, or carried to Iquique, Pisagua, Patillos, and Anto- fagasta by rail, all of these places having connection, by narrow- gauge railways, with the nitrate deposits, and which, consequently, are rapidly becoming the chief centers of nitrate production and export. Halite cmd Glattberite Nitrate cf Sodium FIG. 25. Map of Chilean nitrate region. [After Fuchs and De Launay.] According to the reports of Consul- General Walker, the southern limit of the nitrate fields is in Antofagasta province, latitude 25 45' S., and the northern in latitude 19 12' S., its extreme north and south length being sonic 260 geographical miles and its average width some 2^ miles. This narrow strip of nitrate lands stretches along the eastern slope of the coast range of barren, verdureless mountains which wall 310 THE NON-METALLIC MINERALS. in the Pacific Ocean from the northern limit of Peru to the Straits of Magellan, upon which, for more than 2,000 miles, no rain ever falls and upon which there is no living vegetation. Some of the peaks reach an altitude of 4,000 or 5,000 feet above the sea level, but the usual height of the range is about 2,000 feet. The average distance from the coast to the nitrate beds is about 14 miles, but many of them are not more than 10 miles. The map on the preceding page, from Fuchs and De Launay's Traite* des Gites Mineraux, will serve to show the geographic posi- tion of the deposits. 3. NITRO-CALCITE. Nitro-calcite, or calcium nitrate, CaN 2 O 6 +wH 2 O, is not un- common as a silky efflorescence on the floors and walls of dry lime- stone caverns and may be extracted in considerable quantities from their residual clays by a process of leaching. During the war of 1812 the clays upon the floors of Mammoth Cave, Kentucky, were systematically leached and the dissolved nitrate obtained by evapo- ration and crystallization. The wooden tanks and log pipes for conducting the water are still in a remarkable state of preservation, owing to the dry air of the cavern. The nitrous earths of Wyandotte Cave in southern Indiana, and doubtless of other localities, were similarly treated during these times of temporary stringency. According to the reports of the State geologist l this earth, in its air-dry condition, has the following composition: Loss at red heat 16.50 Silica 20 . 60 Ferric oxide 6 . 03 Manganic oxide 0.75 Alumina 20 .40 Lime 8.06 Magnesia 4.58 Carbonic acid 10-38 Sulphuric acid 6.55 Phosphoric acid 2 .43 Nitric acid 3.50 Chlorides of alkalies and loss 0.32 100.10 1 Geological Report of Indiana, 1878, p. 163. NITRATES. 311 The researches of Muntz and Marcano * have shown that the soils as well as the earth from the floor of caves, in Venezuela and other portions of South America, may be rich in calcium nitrate to an extent quite unknown in other countries. Origin. The source of the nitrates, both of caves and of the Chilean pampas, has been a subject of considerable discussion. There appears little doubt but the deposits in caves and those dis- seminated in soils are due to the nitrifying agencies of bacteria acting upon organic matter whereby the organic nitrogen is con- verted into nitric acid, which immediately combines with the most available bases, be they of lime, soda, or potash. The accumulation of the niter in caves is probably due, as suggested by W. H. Hess (see Bibliography), to the retention by the clay of the nitrates brought in from the surface by percolating waters. In other words, the caves serve merely as receptacles, or store- houses, for nitrates which had their origin in the surface soil. The Chilean nitrate beds are considered by Muntz and Marcano as having a very similar origin. The material being soluble is grad- ually leached out from the soils in which it originated and drained into inclosed salt marshes or inland seas where a double decom- position takes place between the sodium chloride and calcium nitrate, whereby sodium nitrate and calcium chloride are produced. That such a double decomposition may take place has been shown by actual experiment. This is not widely different from the view taken also by W. New- ton. 2 After discussing briefly theories previously advanced, includ- ing Darwin's theory of derivation from decomposing seaweeds accumulated on old sea beaches, and the even less plausible one of its derivation from guano, this writer shows that the plain of Tamaru- gal, within which the deposits lie, is covered by an alluvial soil rich in organic matter. This organic matter, under the now well-known action of bacteria, aided by the prevailing high temperatures of the region, gives rise to nitrates, which, owing to the absence of rains for long periods, accumulate to an extent impossible under Comptes Rendus de 1'Academie des Sciences, CI, Paris, 1885, p. 1265. 2 Geological Magazine, III, 1896, p. 339. 312 THE NON METALLIC MINERALS. less favorable circumstances. Mountain floods, which occur at periods of seven or eight years, swamp the plain, bringing in solution the nitrate drained from the soils of the surrounding slope, to ac- cumulate in the lower levels. On the evaporation of the water this is again deposited. The occurrence of the nitrate so far up the slope of the hills is regarded by Newton as due to the tendency of the nitrate salt, in saturated solutions, to creep up, as in experi- ment it may be seen to creep up and over the sides of a saucer or other shallow dish in which the evaporation is progressing. BIBLIOGRAPHY. M. A. MUNTZ. Recherches sur la formation des gisements de nitrate de soude. Comptes Rendus de 1' Academic des Sciences, CI, 1885, p. 1265. ROBERT HARVEY. Machinery for the Manufacture of Nitrate of Soda. Journal of the Society of Chemical Industry, IV,' 1885, p. 744. RALPH ABERCROMBY. Nitrate of Soda, and the Nitrate Country. Nature, XL, 1889, p. 186. The Nitrate Deposits and Trade of Chile. Engineering and Mining Journal, L, August 9, 1890, p. 164. NICOLAS RUSCHE. Die Saltpetre wiiste in Chile. Vom Fels zum Meer, Pt. 4, 1891-92. G. M. HUNTER. The Santa Isabel Nitrate Works, Toco, Chile. Transactions of the Institute of Engineers and Shipbuilders of Scotland, XXXVI, p. 57. WILLIAM NEWTON. The Origin of Nitrate in Chile. The Geological Magazine, III, 1896, p. 339. W. H. HESS. The Origin of Nitrates in Caves. Journal of Geology, VIII, No. 2, 1900, p 129. X. BDRATES. Of the ten or more species of natural borates but three, or pos- sibly four, are commercial sources of borax, and need consideration here. These are, (i) borax or tincal; (2) ulexite, or boronatrocal- cite; (3) priceite, colemanite, or pandermite, and (4) boracite, or stassfurtite. Sassolite, or native boric acid, occurs chiefly in solution. The intimate association of these minerals renders it advisable to treat of their origin and mode of extraction in common, after giving the composition and general physical characters of each by itself. BORATES. 3*3 i. BORAX OR TINCAL; BORATE OF SODA. Composition. Na 2 B 4 O 7 .ioH 2 O,== boron trioxide, 36.6 per cent; soda, 16.2 per cent; water, 47.2 per cent. Color, white to grayish, and sometimes greenish; translucent to opaque. It crystallizes in short, stout prisms, belonging to the monoclinic system. Hardness, 2 to 2.5; specific gravity, 1.7. Readily soluble in water; taste, sweetish alkaline. 2. ULEXITE; BORONATROCALCITE. Composition. NaCaB 5 O 9 .8H 2 O, = boron trioxide, 43 per cent; lime, 13.8 per cent; soda, 7.7 per cent; water, 35.5 per cent. Color, white, with silky luster. Occurs usually in rounded masses of loose texture, which consist mainly of fine acicular crystals or fibers. In- soluble in cold water, and only slightly so in hot, the solution being alkaline. Hardness, i; specific gravity, 1.65. 3. COLEMANITE. Composition. Ca 2 B G O u .5H 2 O, = boron trioxide, 50.9 per cent; lime, 27.2 per cent; water, 21.9 per cent. Color, milky to yellowish white, or colorless; transparent to translucent. Hardness, 4 to 4.5; specific gravity, 2.41. Insoluble in water, but readily so in hot hydro- chloric acid. Priceite and pandermite are hydrous calcium bo rates closely allied to colemanite, occurring in loosely coherent and chalky or massive forms. 4. BORACITE OR STASSFURTITE ; BORATE OF MAGNESIA. Composition. Mg 7 Cl 2 B 16 O 30 , = boron trioxide, 62. 5 per cent; mag- nesia, 31.4 per cent; chlorine, 7.9 per cent. Color, white to yellow or greenish. In crystals transparent to translucent. Crystals cubic and tetrahedral. Insoluble in water; readily soluble in hydrochloric acid. Hardness, 7; specific gravity, 2.9 to 3. Localities and manner of occurrence of the borates. Throughout what is known as the Great Basin region of the western United States, and in particular that portion including Inyo, Kern, and San Bernar- dino counties in California, and that portion of southwest Nevada THE NON-METALLIC MINERALS. adjoining Inyo County, are numerous inclosed lakes or marshes, the waters of which are sufficiently rich in borates and other sodium salts to allow of their extraction on a commercial scale. At least ten of these marshes have been noted along the California-Nevada line, the most widely known being Teels, Columbus, and Rhodes marshes, and Fish Lake Valley in Nevada, and Searles Marsh in San Bernardino County, California. A detailed description of the last named will serve all purposes of illustration here. * Locally considered, the marsh lies near the center of an exten- sive mountain-girdled plain, to which the phrases "Alkali Flat," "Dry Lake," "Salt Bed," and "Borax Marsh" have variously been applied, the contents and physical features of the basin- shaped depression well justifying the several names. It is, in fact, a dry lake, the bed of which has been filled up in part with the several substances named. Its contents consist of mud, alkali, salt, and borax, largely supplemented with volcanic sand. This depression, which has an elevation of 1,700 feet above sea level, and an irregular oval shape, is about 10 miles long and 5 miles wide, its longitudinal axis striking due north and south. It is sur- rounded on every side but the south by high mountains, the Slate Range bounding it on the east and north, and the Argus Range on the west. There is no doubt but this basin was once the bed of a deep and wide-extended lake, the remains of a former inland sea. The shore line is distinctly visible along the lower slopes of the surrounding mountains at an elevation of 600 feet above the surface of the marsh. Farther up, one above the other, faint marks of former water lines can be seen, showing the different levels at which the surface of the ancient lake has stood. In the course of time the lake became extinct, having been filled with the sediments from the adjacent mountains. What may have been the depth of the lake has not yet been ascer- tained, borings put down 300 feet having failed to reach bed rock. These borings, commenced in 1878, disclosed the following under- lying formations: 1 From the Tenth Annual Report of the State Mineralogist of California, 1890, p. 534. BORATES, 3 I S First, 2 feet of salt and thenardite (Na 2 SO 4 ) ; second, 4 feet of clay and volcanic sand, containing a few crystals and bunches of hanksite (4Na 2 SO 4 ,Na 2 CO 3 ) ; third, 8 feet of volcanic sand and black, tenacious clay, with bunches of trona, of black, shining luster, from inclosed mud; fourth, 8-foot stratum, consisting of volcanic sand containing glauberite, thenardtie, and a few flat, hexagonal crystals of hanksite; fifth, 28 feet of solid trona of uniform thickness; sixth, 2o-foot stratum of black, slushy, soft mud, smelling strongly of sulphureted hydrogen, in which there are layers of glauberite, soda, and hanksite. The water has a density of 30 Baume; seventh, 230 feet (as far as explored) of brown clay, mixed with volcanic sand and permeated with sulphureted hydrogen. As is the case with all salines of like character, this has no outlet, the water that comes into it escaping only by evaporation, which process goes on here very rapidly for two-thirds of the year. While most of the water contained in this basin is subterranean, a little during very wet winters accumulates and stands for a short time on portions of the surface. In no place, however, does it reach a depth of more than a foot or two, hardly anywhere more than 3 or 4 inches. Within the limits of the actively producing portion of the marsh, which covers an oblong area of about 1,700 acres, the water stands on a tract of some 300 acres for a longer period than it does elsewhere: but even here it nowhere reaches a depth of more than a foot. Between this 3oo-acre tract and the main flat lying a little lower there interposes a slight ridge, which prevents the surface water from escaping to the lower ground. The water of the lake is of a dark-brown color, strongly impreg- nated with alkali, and has a density of 28 Baume. The salts ob- tained from it by crystallization contain carbonate and chloride and borate of sodium, with a large percentage of organic matter. Summarized, the following minerals have been found associated with the borax occurring in the Searles Ma h: Anhydrite, calcitc, celestite, cerargyrite, colemanite, dolomite, embolite, gay-lussite, glauberite, gypsum, halite, hanksite, natron, soda, niter, sulphur, thenardite, tincal, and trona, the most of these occurring, of course, in only minute quantities- There is, however, reason to believe 316 THE NON METALLIC MINERALS. that hanksite will yet be found abundantly, both here and in the other salines of this region. The submerged tract above described is called the "Crystal Bed,'* the mud below the water being full of large crystals, which occur in nests at irregular intervals to a depth of 3 or 4 feet. Many of these crystals, which consist of carbonate of soda and common salt with a considerable percentage of borate, are of large size, some of them measuring 7 inches in length. The water 15 feet below this stratum of mud contains, according to Mr. C. N. Hake, who made, not long since, a careful examination of these deposits, carbonate of soda, borax, and salts of ammonia. The ground in the immediate vicinity, a dry, hard crust about i foot thick, contains, on the same authority : Sand 50% Sulphate of soda 16% Common salt 1 2% Carbonate of soda 10% Borax 12% The borax here occurs in the form of the borate of soda only, no ulexite (borate of lime) having yet been found. About 1890 it was discovered that these marsh deposits were all secondary, the borax contents being derived from bedded deposits in the Tertiary lake sediments of the surrounding hills. The marshes were, therefore, very generally abandoned in favor of the beds. These are now being worked by the Pacific Coast Borax Company. The most important deposit thus far worked is at a locality appropriately named Borate, some 12 miles north of Daggett in the old Calico Mining District. The mineral colemanite the borate of lime occurs in beds of from 3 to 5 feet thickness interstratified with lake sediments which are themselves composed of semi-indurated clays, sandstones, and coarse conglomerates with sheets of volcanic tuffs and lava. At the mine, according to Messrs. W. H. Storms 1 and M. R. Campbell, 2 1 Eleventh Annual Report of the State Mineralogist of California, 1892, p. 345. 3 Bulletin No. 200, U. S. Geological Survey, Series A, Economic Geology, 17. O T II BORATES. 317 there are two outcrops of the colemanite some 50 feet apart, repre- senting two distinct beds or perhaps a repetition by folding of what was originally one and the same bed. The beds throughout their extent vary from 5 to 30 feet in thickness, and have a strike approxi- mately east and west, dipping to the south from 10 to 45. The lake beds extend across the mountains for a distance of 8 miles, but the borax deposit, so far as yet discovered, has a practical limit of not above a mile and a half. The illustration here given conveys better than words an idea of the character of the desolate country in which the borax occurs, and also the method of mining. Borax in the form of colemanite (priceite) has been found about 5 miles north of Chetco, in Curry County, Oregon, the material occurring in a hard, compact form in layers between slate and steatite, sometimes in cavities and fissures in the slate, and sometimes in rounded and bowlder-form masses of all sizes up to 200 pounds' weight in the steatite. A borax deposit in form somewhat resembling the marsh deposits of Nevada and California already referred to occurs in Harney County, southeastern Oregon. The region is extremely flat and bare of all vegetation, the immediate surface of the ground being covered for a depth of several inches with a white incrustation con- sisting of borate of soda contaminated with carbonate, sulphate, and chloride of sodium. 1 The chief foreign sources of borax salts are Northern Chile, Stassfurt in Germany, Italy, Asia Minor, and Thibet. The Chilean mineral is ulexite and is reported as occurring throughout the province of Atacama and the newly acquired por- tions of Chile. Ascotan, which is now on the borders of the Republic, but formerly belonged to Bolivia, and Maricunga, which is to the north of Copeapo, are the places which have proved most successful commercially. The crude material occurs in both places in lagoons or troughs, which, instead of being entirely filled with common salt, as is usually the case in the desert, contain zones or layers of embedded boronatrocalcite. The lagoons of Maricunga lie about 64 kilometers from the nearest railway station, and are esti- 1 W. B. Dennis, Engineering and Mining Journal, April 26, 1902, p. 581. 318 THE NON-METALLIC MINERALS. mated to cover 3,000,000 square meters. The boronatrocalcite oc- curs in beds alternating with layers of salt and salty earth. The raw material contains, in the form of gypsum and glauber- ite, a large amount of calcium sulphate. Dana also mentions ulexite as occurring in the form of rounded masses from the size of a hazelnut to that of a potato in the dry plains of Iquique, where it is associated with pickeringite, glauberite, halite, and gypsum. The German mineral is boracite (stassfurtite) and is found in small granular masses associated with the salt deposits of Stassfurt. In Italy sassolite, or crystallized boric acid, has long been obtained by the evaporation of the water of hot springs in Sienna, in Tuscany. Concerning the deposits of Asia Minor little is accurately known. The mineral is pandermite (colemanite), which is found in thick white lumps at Suzurlu, south of the sea of Marmora. Borax or tincal, from Thibet, in North- ern India, was probably the first of the boron salts to be utilized. It is stated to be brought on the backs of sheep from the lakes in which it is formed across the Himalayas to the shipping points in India. Methods of mining and manufacture. At the East Calico Cole- manite Mine, in San Bernardino County, the mineral is taken out in the same manner as ores of the precious metals. Inclined shafts are sunk, drifts and levels run, and stopes carried up as in any other mine The material, when hoisted to the surface, is loaded into wagons arid hauled to Dagget, whence it is shipped to the works at Alameda, where it is purified. At Searles's marsh the overlying crust mentioned constitutes the raw material from which the refined borax is made. The method of collecting it in the past has been as follows: When the crust, through the process of efflorescence, has gained a thickness of about i inch, it is broken loose and scraped into windrows far enough apart to admit the passage of carts between them, and into which it is shoveled and carried to the factory located on the northwest margin of the flat, i to 2 miles away. As soon as removed, this incrustation begins again to form, the water charged with the saline matter brought to the surface by the capillary attraction evaporating and leaving the salt behind. This process having been suffered to go on for three or four years, a BO RATES. 3*9 crust thick enough for removal is again formed, the supposition being that this incrustation, if removed, will in like manner go on reproducing itself indefinitely. 1 At the Harney County, Oregon, works the crude material is care- fully shoveled up during the summer into small conical heaps, the crust continually renewing itself, so that the same ground is worked over repeatedly. This crude material, which contains from 5 to 20 per cent boric acid, is refined by throwing into tanks of hot water into which small amounts of chlorine or sulphuric acid are introduced. The various salts are all dissolved and subsequently separated one from another by fractional crystallization. 1 In order to determine the proportionate growths of the various salts contained in this crust while undergoing this recuperative process, analyses were made on sam- ples representing respectively six months', two, three, and four years' growth. From the ground from which these were taken the crust had been removed several times during the preceding twelve years. The analysis of samples gave the following results: Six Two Three Pour Constituents. Months' Years' Years' Years' Growth. Growth. Growth. Growth. Sand eg o r r A C2 A r 7 ? Carbonate of soda 5- 2 5- 8.1 8.0 Sulphate of soda 11.7 6.7 16.6 16.0 Chloride of soda 10.9 2O.O ii. i n.8 Borax 14. 2 12 O ii 8 IO Total. . . IOO.O IOO O IOO.O IOO.O From this list it will be seen that the first six months' growth is richest in borax, and that the proportion of carbonate of soda to borax increases with time. The presence of so much sand as is here indicated is caused by the high winds that blow at intervals, bringing in great quantities of that material from the mountains to the west. This sand, it is supposed, facilitates the formation of the surface crust by keeping the ground in a porous condition. 320 THE NON-METALLIC MINERALS. XL URANATES. i. URANINITE; PITCHBLENDE. Composition very complex, essentially a uranate of uranyl, lead, thorium, and other metals of the lanthanum and yttrium groups. The mineral is unique in containing nitrogen, being the only one among the constituents of the primary rocks of the earth's crust in which the presence of this element has been thus far determined. 1 The analyses given below are for the most part by Hillebrand, to whom is due the credit of a large share of the present knowledge on the subject. , . Locality. UO 3 . UO 2 . ThO 2 . CeO 2 . La ? O 3 . Y 2 3 . , Glastonbury, Connecticut. . North. Carolina, 23-03 C0.83 59-93 3Q.3I 2.78 II 0.26 '10 O ^O o 20 Annerod, Norway .... -> "^ 30. 63 46.13 6.00 0.18 O.27 in Tohanngeorgenstadt SO. 3O 22. ^T. Locality. PbO. CaO. N. H 2 0. Fe 2 3 . Misc. Glastonbury, Connecticut. . North Carolina. ......... 3.08 4.20 O.II 0.81; 2.41 0.37 0-43 1. 21 0.29 I. II 4.8 Annerod Norway 9 04. O 37 I 17 O 74 O2? 4 66 Tohann cr eorgenstadt 6 30 I OO O O2 317 w.*3 O 21 5r o oo Several varieties of uraninite are recognized, the distinctions being based upon the relative proportions of the two oxides UO 2 and UO 3 (see analyses above). Inasmuch, however, as these variations may be due merely to oxidation they need not be taken into considera- tion here. When crystallized the mineral assumes octahedral and dodecahedral forms, more rarely cubes. Hardness, 5.5; specific gravity, 9 to 9.7. Color, grayish, greenish to velvet-black, streak brown; fracture conchoidal, uneven. The massive and probably amorphous variety, containing few of the rarer earths and no nitrogen, is known under the name of pitchblende. This last is the chief com- mercial source of uranium salts. Through oxidation and hydration the mineral passes into gummite, a gum-like yellow to brown or red mineral of a hardness of but 2.5 to 3 and specific gravity of 3.9 to 4.2. 1 The mineral has since been found to contain some 0.23 per cent of the new elements helium and argon. URANATES. 3 2 I Localities and mode of occurrence. Uraninite occurs as a pri- mary constituent of granitic rocks and as a secondary mineral, with sulphide ores of silver, lead, gold, copper, etc. In this last form, according to Dana, it is found at Johanngeorgenstadt, Marienberg, and Schneeberg, Saxony ; at Joachimsthal and Pribram, in Bohemia, and Rezbanya, in Hungary. Considerable quantities have been mined from the tin-bearing lodes of Cornwall, England. The crystallized variety broggerite is found in a pegmatite vein near Annerod, Norway, and the variety cleveite in a feldspar quarry at Arendal. In the United States the mineral has been found in small quantities in several localities, but only those of Mitchell and Yancey counties, North Carolina, where the mineral occurs partially altered to gummite and uranaphane, in mica mines; Llano County, Texas; Black Hawk, near Central City, Gilpin County, Colorado, and the Bald Mountain district of the Black Hills of South Dakota need here be mentioned. Of the above the Cornwall localities are at present of greatest consequence, having during 1890 yielded some 22 tons of ore, valued at some 2,200 ($11,000). During 1891, it is stated, the output was 31 long tons, valued at 620, and in 1892, 37 tons, valued at 740. The next most important locality is that of Joachimsthal, in Bohemia, where 22.52 metric tons of ore were produced in 1891 and 17.71 tons in 1892, the value being some 1,000 florins a ton. In the Cornwall mines the pitchblende is stated 1 to occur in small veins crossing the tin-bearing lodes. At the St. Austell Consols Mines it was associated with nickel and cobalt ores; at Dolcoath with native bismuth and arsenical cobalt in a matrix of red quartz and purple fluorspar; at South Tresavean with kupfer-nickel, native silver, and argentiferous galena. At the Wood Lode, Russell dis- trict, in Gilpin County, Colorado, pitchblende was found in the form of a lenticular mass in one of the ordinary gold-bearing lodes trav- ersing the gneiss and mica schists of the district. The body occurred some 60 feet below the surface and was some 30 feet long by 10 feet deep and 10 inches thick. The mass yielded some 4 tons of ore carrying 70 per cent oxide of uranium. 1 The Mineral Industry, II, p. 572. 322 THE NON-METALLIC MINERALS. Other natural uranium compounds, but which at present have no use in the arts, are as below: Torbernite, a hydrous phosphate of uranium and copper; autunite, a hydrous phosphate of uranium and calcium; zeunerite, an arsenate of uranium and copper; urano- spinite, an arsenate of uranium and calcium; uranocircite, a phos- phate of barium and uranium; phosphuranylite, a hydrous uranium phosphate; trogerite, a hydrous uranium arsenate; walpurgite, prob- ably an arsenate of bismuth and uranium ; and uranosphaerite, a uranate of bismuth. Uses. Uranium is never used in the metallic state, but in the form of oxides, or as uranate of soda, potash, and ammonia, finds a limited application in the arts. The sesquioxide salt imparts to glass a gold-yellow color with a beautiful greenish tint, and which exhibits remarkable fluorescent properties. The protoxide gives a beautiful black to high-grade porcelains. The material has also a limited application in photography. Recently the material has been used to some extent in making steel in France and Germany, but the industry has not yet passed the experimental stage. It has been stated that the demand, all told, is for about 500 tons annually. Should larger and more constant sources of supply be found, it is probable its use could be considerably extended. According to Nordenskiold, 50,000 worth of uranium minerals are consumed every year, the various salts produced being used in porcelain and glass manufacture, in photography, and as chemical reagents. 1 2. CARNOTITE. The name carnotite was given in 1899 by MM. E. Cumenge and C. Friedel to a beautiful canary-yellow ocherous pigment which was found impregnating a siliceous sandstone in Montrose County, Colorado. Material from the same and other sources has since been examined by Dr. W. F. Hillebrand 2 whose results show.the material to be not a simple mineral but a mixture made up in large part of an impure uranyl-vanadate of potash and the alkaline earths. The 1 The material has of late in the public mind at least possessed an almost sen- sational interest in connection with the discovery of its radio-active properties, and the supposed new elements radium and polonium. 2 American Journal of Science, X, August, 1900. URANATES. composition of material from (i) the Copper Prince claim, Roe Creek, and (2) the Yellow Boy claim, La Sal Creek, and in Mon- trose County, as shown by Hillebrand's analyses, is given below: ANALYSES OF CARNOTITE FROM COLORADO. I. I I. A. B. C. A. B. Insoluble 7.10 8.34 IQ.OO 10.33 UO,. tU.So C2 2< 4.7 4.2 C2 28 V,C1 O.77 1.64 Nad' O 21 O 21 Insoluble residue (at 100 C.) 38.43 85.30 13 86 99.16 Total chloride calculated as NaCl equals 1.16 per cent. This, calculated on TOO parts anhydrous Na 2 SO 4 , equals 3.22 per cent NaCl. This solid soda is stated to have a depth of some 20 or 30 feet. Above the solid soda occurs the superficial layer of pure white crystallized sulphate of soda. This is formed by solution in water of the upper part of the lower body, the crystals being deposited by evaporation or by cooling, or by the two combined. A little rain in the spring and autumn furnishes this water, as do also innumerable small, sluggishly flowing springs present in all the lakes. But on account of the dry air of this arid region the surface is generally dry, or nearly so, and in midsummer the white clouds of efflorescent sulphate that are whirled up by the ever-blowing winds of Wyoming can be seen for miles. Even should there be a little water present there is no difficulty in gathering the crystals by the train load. The spring, however, is the worst season of the year, on account of the warm weather and of the rains conditions unfavorable to the formation of crystals. The layer of this white sulphate is from 3 to 12 inches in thickness. When the crystals are removed the part laid bare is soon replenished by a new crop. The following is an analysis of the purest of this white sulphate of soda, calculated upon an anhydrous basis, that being the con- dition, of course, in which it would be used: Na 2 SO 4 99.73 MgCl 2 26 Insoluble Trace. 99.99 336 THE NON-METALLIC MINERALS. Below is given an analysis of the water of the Track lake: Density = 14^ Tw. (=1.0725 specific gravity). Ten cubic centi- meters contain: Grams. Per Cent. Na 2 SO 4 0.7563 = 92.23 CaSO 4 0.0146= 1.79 MgSO 4 0.0070 = .85 MgCl 2 0.0300 = 3.66 Na 2 B 4 O 7 0.0121 = 1.47 Total solids 0.8200 100.00 Total solids by evaporation, 0.8240 One cubic foot of this water contains 10.72 pounds of pure crys- tallized sulphate of soda. 1 Other soda deposits occur in Carbon and Natrona counties, and still others are reported in Fremont, Johnson, and Sweetwater counties. It has been stated 2 that glauber salts has been found on the bottom of Bay of Kara Bougas, an inlet of the Caspian Sea, in deposits sometimes a foot in thickness. 5. GLAUBERITE. Composition. Sodium and calcium sulphate. Na 2 SO 4 .CaSO 4 , = sulphur trioxide, 57.6 per cent; lime, 20.1 per cent; soda, 22.3 per cent. This is a pale yellow to gray salt, partially soluble in water leaving a white residue of sulphate of lime and with a slightly saline taste. On long exposure to moisture it falls to pieces, and hence is to be found only in protected places or arid areas. It occurs associated with other sulphates and carbonates, as with thenardite and mirabilite at Borax Lake, in San Bernardino County, California, and with halite in rock salt at Stassfurt and other European locali- ties. 6. THENARDITE. Composition. Anhydrous sodium sulphate. Na 2 SO 4 , = sulphur trioxide, 43.7 per cent; soda, 56.3 per cent. Color when pure, white, 1 Journal of the Franklin Institute, CXXXV, 1893, pp. 53, 54, 56. 3 Engineering and Mining Journal, LXV, 1898, p. 310. SULPHATES. 337 translucent to transparent; hardness, 2 to 3; specific gravity, 2.68; brittle. In cruciform twins or short prismatic forms roughly striated. Readily soluble in water. Is found in various arid countries, as on the Rio Verde in Arizona, at Borax Lake, California, and Rhodes Marsh in Nevada, associated with other salts of sodium and boron. 7. EPSOMITE; EPSOM SALTS. Composition. Sulphate of magnesia MgSO 4 +7H 2 O, = sulphur trioxide, 32.5 per cent; magnesia, 16.3 per cent; water, 51.2 per cent. This is a soft white or colorless mineral readily soluble in water and with a bitter saline taste. It is a constant ingredient of sea water and of most mineral waters as well. Being readily soluble it is rarely met with in nature except as an efflorescence in mines and caves. In the dry parts of the limestone caverns of Kentucky, Ten- nessee, and Indiana it occurs in the form of straight acicular needles in the dirt of the floor, and in peculiar recurved fibrous and columnar forms or in loose snow-white masses on the roofs and walls. In all these cases it is doubtless a product of sulphuric acid set free from decomposing pyrites combining with the magnesia of the limestone. It is stated that at the so-called "alum cave" in Sevier County, Tennessee, masses of epsomite, very pure and nearly a cubic foot in volume have been obtained. The material in all these cases is of little value, the chief source of the commercial supply being that obtained as a by-product during the manufacture by evaporation of common salt (sodium chloride). In Albany County, Wyoming, are several lakes, the largest of which has an area of but some 90 acres, in which deposits of epsom salts are formed on a very large scale, but which are of little com- mercial value, owing to cost of transportation. The material forms compact, almost snow-white aggregates of small acicular crystals of a high degree of purity. According to Prof. W. C. Knight, 1 the deposits are situated upon a high plateau about three miles north of Rock Creek, and lie in a huge, undrained depression that is deepest at its southern end, where 1 Engineering and Mining Journal, February 14, 1903. 338 THE NON-METALLIC MINERALS. it is about two miles wide and lies a hundred feet or more below the level of the surrounding country. From this deepest portion a rather broad, shallow valley extends to the northwest for several miles and contains numerous small and a few larger deposits of sodium and magnesium salts which have for a long time been tributary to the large epsomite deposit of about 90 acres in extent occupying the lowest basin. The deposits are often covered with water in early spring or after a hard storm, but this soon evaporates and leaves them solid epsomite or an accumulation of mud, sand, and epsomite, the depth of which has been found by digging to exceed ten feet. Knight regards the salts as having been derived from the decom- posing Triassic or Permian red sandstones which prevail in the vicinity, the material having been leached out and transported by water. Both epsomite and mirabilite occur in the rocks and are separated from one another by a natural method of differential crystallization, the epsomite being more soluble, remaining longest in solution and being laid down at a greater distance from the original source. The composition of the deposits is shown in the accompanying analyses by Dr. Slosson of the University of Wyoming, No. i being taken from near the head of the gulch, and No. 6 from the large deposit at the greatest distance from the source, the others from intermediate points: No. i. No. 2. No. 3. No. 4. No. 5. No. 6. Na SO 4 Qf 4.6 O2 CJ. CQ OO 4.7 74. 5Q jg 2^ 6l NaCl . 0.28 0.28 O.^O M-/-/H- 1.86 I .OO ; 28 MgSO 4 . 4.26 >.2Q 48.60 t;o.i6 SQ.82 70. 1 1 CaSCX. , 1. 80 8. POLYHALITE. 9. KAINITE. IO. KIESERITE. For description of these minerals see under Halite, p. 50. II. ALUMS. Under this head are included a variety of ^ minerals consisting essentially of hydrous sulphates of aluminum or iron, with or with- out the alkalies, and which are not always readily distinguished SULPHATES. 339 from one another but by quantitative analyses. The principal varie- ties are kalinite, tschermigite, mendozite, pickeringite, apjohnite,, halotrichite, and alunogen. Aluminite and alunite are closely related chemical compounds, but differ in hardness and general physical qualities and in being insoluble except in acids. Although possible sources of alum, none of these minerals have been to any extent utilized in the United States, owing to a lack of quantity or inaccessibility, the main source of the alum of commerce .being cryolite, bauxite, and clay, as elsewhere noted. Kalinite is a native potash alum; composition K 2 SO 4 .A1 2 (SO 4 ) 3 4- 24H 2 O, = sulphur trioxide, 33.7 per cent; alumina, 10.8 per cent; potash, 9.9 per cent; water, 45.6 per cent, or, otherwise expressed, potassium sulphate, 18.1 per cent; aluminum sulphate, 36.3 per cent; water, 45.6 per cent. Hardness, 2 to 2.5; specific gravity, 1.75. This in its pure state is a colorless or white transparent mineral, crystallizing in the isometric system, readily soluble in water, and characterized by a strong astringent taste. In nature it occurs as a volcanic sublimation product, or as a secondary mineral due to the reaction of sulphuric acid set free by decomposing iron pyrites upon aluminous shales. Its common mode of occurrence is, therefore, in volcanic vents or as an efflorescence upon pyritiferous and aluminous rocks. Being so readily soluble, it is to be found in appreciable amounts in humid regions only where protected from the rains, as in caves and other sheltered places. So far as known to the author, the mineral is nowhere found native in such quantities as to have any great commercial value. Tschermigite is an ammonia alum of the composition (NH 4 ) 2 SO 4 .A1 2 (SO 4 ) 3 +24H 2 O,= aluminum sulphate, 37.7 per cent; ammonium sulphate, 14.6 per cent; water, 47.7 per cent. So far as reported this salt has been found only at Tschermig and in a mine near Dux, Bohemia. It is obtained artificially from the waste of gas works. Mendozite is a soda alum of the composition Na 2 SO 4 .Al 2 (SO 4 )3+ 24H 2 O, = sodium sulphate, 15.5 per cent; alumin- um sulphate, 37.3 per cent ; water, 47.2 per cent. The mineral closely resembles ordinary alum, and has been reported from Mendoza, in 1 Bulletin No. 14, October, 1893, Wyoming Experiment Station. 34 THE NON-METALLIC MINERALS. the Argentine Republic, hence the name. Pickeringite is a mag- nesium alum of the composition MgS O 4 .A1 2 (SO 4 ) 3 + 2 2H 2 O, = alu- minum sulphate, 39.9 per cent; magnesium sulphate, 14 per cent; water, 46.1 per cent. The mineral is of a white, yellowish, or sometimes faintly reddish color, of a bitter, astringent taste, and occurs in acicular crystals or fibrous masses. Halotrichite has the composi- tion FeSO 4 .Al 2 (SO 4 ) 3 +24H 2 O, = aluminum sulphate, 36.9 per cent; ferrous sulphate, 16.4 per cent; water, 46.7 per cent. The mineral is of a white or yellowish color, and of a silky, fibrous structure,, hence the name from the Greek word As, salt, and &pi, a hair. Apjohnite has the formula MnSO 4 .Al 2 (SO 4 ) 3 +24H 2 O, = manganese sulphate, 16.3 per cent; aluminum sulphate, 37 per cent; water, 46.7 per cent. It occurs in silky or asbestiform masses of a white or yel- lowish color, and tastes like ordinary alum. It has been found in considerable quantities in the so-called "Alum cave" of Sevier County, Tennessee. According to Safford : * "This is an open place under a shelving rock. . . . The slates around and above this contain much pyrites, in fine particles and even in rough layers. . . . The salts are formed above and are brought down by trickling streams of water. . . . Fine cabinet specimens could be obtained, white and pure, a cubic foot in volume." Dana states that the cave is situated at the headwaters of the Little Pigeon, a tributary of the Tennessee River, and that it is prop- erly an overhanging cliff 80 or 100 feet high and 300 feet long, under which the alum has collected. It occurs, according to this authority, in masses, showing in the cavities fine transparent needles with a silky luster, of a white or faint rose tinge, pale green or yellow. Epsomite and melanterite occur with it. Alunogen has the compo- sition A1 2 (SO 4 ) 3 + i8H 2 O,== sulphur trioxide, 36 per cent; alumina, 15.3 per cent; water, 48.7 per cent; hardness, 1.5 to 2; specific gravity, 1.6 to 1.8. This is a soft white mineral of a vitreous or silky luster, soluble in water, and with a taste like that of the common alum of the drug stores. It occurs in nature both as a product of sublimation in volcanic regions, and as a decomposition product 1 Geology of Tennessee, 1869, p. 197. SULPHATES. 341 from iron pyrites (iron disulphide) in the presence of 'aluminous shales. So far as the present writer is aware, the native product has no commercial value, being found (on account of its ready solubility) in too sparing quantities in the humid East, while the known deposits in the arid regions are remote and practically inac- cessible. A white, fibrous variety is stated by Dana to occur in large quantities at Smoky Mountain, in North Carolina, and large quan- tities of an impure variety, often of a yellowish cast, are found in. Grant County, on the Gila River, about 40 miles north of Silver- City, New Mexico. The mineral is also found in Crooke and 1 . Fremont counties, Wyoming; in Schemnitz, Hungary, and in Japan,- According to W. P. Blake, 1 the Gila River deposit occurs in a. region of about one-half mile square occupied mainly by volcanic beds lying nearly horizontally. Extensive solfataric action, or pos- sibly decomposition of disseminated pyrite, have resulted in the production of deposits of the aluminous sulphate in the form of a crust upon the outer portions of the rocks, attended by the deposition of siliceous crusts and the separation of ferric sulphate, while the rocks traversed by the solutions have been deprived, in part at least, of their silica and alkalies, with the formation of bauxite. The alunogen is usually bluish white, granular, but non- crystalline. % Material from this locality, analyzed in the laboratories of the United States Geological Survey, yielded results as below: 2 Alumina (A1 2 O 3 ) I S-5 2 Sulphur trioxide (SO 3 ) 34-43 Water (H 2 O) 42.56 Insoluble residue 7.62 Total 100.13 An asbestiform halotrichite from the same locality yielded: Alumina (A1 2 O 3 ). 7.27 Iron protoxide (FeO) I 3-59 Sulphur trioxide (SO 3 ) 37-iQ Water 40.62 Insoluble residue 0.50 Total 99.17 1 Transactions of the American Institute of Mining Engineers, XXIV, 1894, p. 572. 2 American Journal of Science, XXVIII, 1884, p. 24. 342 THE NON-METALLIC MINERALS. In New South Wales alunogen is commonly met with as an efflo- rescence in caves and under sheltered ledges of the Coal Measure sandstone, usually with epsomite, as at Dabee, County Phillip; Wallerawang and Mudgee road, County Cook; the mouth of the Shoalhaven River, and other places. It is also found in the crevices of a blue slate at Alum Creek, and at the Gibraltar Rock, County Argyle, and occurs as a deposit, with various other salts, from vol- canic vents at Mount Wingen, County Brisbane, together with native sulphur in small quantities; and at Appin, Bulli, and Pitt Water, County Cumberland; Cullen Bullen, in the Turon district, County Roxburgh; Tarcutta, County Wynyard; Manero; Wingello Siding, and Capertee. A specimen in the form of fibrous masses, made up of long, acicular crystals of a white, silky luster, like satin spar, found as an efflores- cence in a sandstone cave near Wallerawang, was found to have the following composition: Water 47.585 Matter insoluble in water J -o79 Alumina 15-198 Sulphuric acid 34-635 Soda .931 Potash 337 Loss .235 Total 100.000 Aluminite. Aluminite is a dull, lusterless, earthy aluminum sul- phate of the composition indicatedb y the formula A1 2 O 3 .SO 8 ,9H 2 O, = sulphur trioxide, 23.3 per cent; alumina, 29.6 per cent; water, 47.1 per cent. It is soluble only in acids, white in color, opaque, and occurs mainly in beds of Tertiary and more recent clays. Alunite. Composition K 2 O.3A1 2 O 3 .4SO 3 ,6H 3 O, = sulphur triox- ide, 38.6 per cent; alumina, 37.0 per cent; potash, 11.4 per cent; water, 13.0 per cent. Hardness, 3.5 to 4; specific gravity, 2.58 to 2.75. This mineral occurs native in the form of a fibrous, or compact, finely granular rock of a dull luster somewhat resembling certain varieties of aluminous limestones. It is infusible, and soluble only in sulphuric acid. The more compact varieties are so hard and tough as to be used for millstones in Hungary. No deposits of such SULPHATES. 343 extent as to be of economic importance are known within the limits of the United States. Alunite as an alteration product of rhyolite has been described by Whitman Cross 1 as occurring at the Rosita Hills in Colorado, the alteration being brought about through the influence of sulphurous vapors incident to the volcanic outbursts. The altered rhyolite as shown by analyses had the following compo- sition: Silica, 65.94 per cent; alumina, 12.95 P er cent 5 potash, 2.32 per cent ; soda, 1.19 per cent ; sulphur trioxide, 12.47 P er cent > water, 4.47 per cent; Fe 2 O 3 , etc., 0.55 per cent. This indicates that the rock is made up of alunite and quartz, in the proportion of about one-third of the former to two-thirds of the latter. The most noted occurrences of alunite are at Tolfa, near Rome; Montioni, in Tus- cany, Italy ; Musaz, in Hungary ; on the islands of Milo, Argentiera, and Nevis, in the Grecian Archipelago ; Mount Dore, in France, and at Bulledelah, in New South Wales. At the last-named locality the mineral occurs in compact, micro-crystalline forms of a slight flesh- pink tint, in a large deposit forming the summit of a ridge about three-fourths of a mile long by one-half a mile wide, and rising about 1,000 feet above the level of Lyall Creek, on which it is situated. Viewed from the creek it presents a massive outcrop resembling limestone. It yields from 60 to 80 per cent of alum upon roasting, lixiviating, and evaporating. 2 Alunite from the mines at Tolfa varies considerably in composi- tion. The crystallized variety contains about 32 per cent alumina, whereas the cruder specimens which contain a large quantity of silica have only about 17.5 per cent. The following is an analysis of an average sample : 3 Alumina 27.60 Sulphuric acid 2 9-74 Potash 7.55 Water 11.20 Iron i. 20 Silica 22.71 Total. . .100. oo 1 American Journal of Science, XLI, 1891, p. 468. 2 Catalogue of New South Wales Exhibits, World's Columbian Exposition, Chicago 893, Dept. E, p. 358. 3 Journal of the Society of Chemical Industry, I, 1882, p. 501. 344 THE NON-METALLIC MINERALS. Alum Slate or Shale is a name given to fine-grained arena- ceous rocks of variable composition, but consisting essentially of siliceous and feldspathic sands and clays with disseminated iron pyrites. The following analyses from Bischof's Chemical Geology will serve to show their varying nature: Constituents. I. II. III. Silica . . 6e 44. 72 4O Alumina.. . 14. 8? 16 4^ IO 73 Iron oxides . ... I.Os 2 27 Lime .1"? .17 4O Magnesia 1.34 I 48 I OO Potash 4..CQ 5.08 Soda 48 ?1 Iron pyrites. I 2 \ 2*26 7r -3 Carbon and water Undet. Undet. JJ 25.04 (I) An alum slate from Opsloe, near Christiania, Norway, (II) from Bornholm, and (HI) from Garnsdorf, near Saalfeld, Prussia. Concerning No. Ill it is stated that on the roof of the adit, driven into the slate, there are almost everywhere yellow or white opaque stalactites, and more rarely a green transparent deposit is produced. Both consist of hydrated basic sulphate of alumina and peroxide of iron. In the former, iron predominates; in the latter, alumina. Both substances are quite insoluble in water. From shales and slates of this type the alum is obtained by allowing the crushed material to undergo prolonged weathering or a roasting process. The essential part of the reaction consists in oxidizing the bisulphide to the condition of a sulphate and finally into iron sesquioxide, with separation of free sulphuric acid, which attacks the alumina, forming an equivalent quantity of sulphate of aluminum. So far as is known this process is not now carried on in the United States. The alum shale of the English Upper Liassic formation consists of hard blue shale with cement stones. On exposure to the air it gradually becomes incrusted with sulphur, and occasionally with alum. In composition the alum shale is as follows : HYDROCARBON COMPOUNDS. 345 Iron sulphide 8.50 Silica 51-16 Iron protoxide 6. 1 1 Alumina 18.30 Lime 2.15 Magnesia 0.90 Sulphuric acid 2.50 Potash .- Trace. Soda Trace. Carbon 8.29 Water 2.00 Total 99.91 From this shale potash-alum was formerly made near Whitby and Redcar, the aluminum sulphate being extracted from the shale, and the potash-salt being added. The trade which since the days of Queen Elizabeth has been largely carried on, has now almost passed away, as alum is now manufactured in other places from coal shale. Alum works formerly existed at the Peak, Robin Hood's Bay, Stow Brow, Sandsend, Kettleness, Lofthouse (Loftus), Os- motherly, etc. 1 XIII. HYDROCARBON COMPOUNDS. Under the name hydrocarbon compounds are included a variety of substances differing at times widely in physical properties and in the proportional amounts of their main constituents, but alike in being composed essentially of carbon and hydrogen. None of the series crystallize in nature, and as a rule the chemical composition is so variable as to render futile all attempts at classification on a mineralogical basis. In practice it is customary to divide them into two main groups, (i) The Coal Series, (2) The Bitumen Series. * Geology of England and Wales, p. 279. 346 THE NON-METALLIC MINERALS. I. THE COAL SERIES. I Here are included a variety of more or less oxidized hydrocarbons, differing considerably in their physical properties and in chemical composition, but alike in that they have originated through the accumulation and -decomposition of plant debris largely out of reach of the oxidizing influence of the air. As to the method of this accumulation there has from time to time been more or less discussion. By many the coal beds are regarded as having resulted from the gradual accumulation, in place, of organic matter growing on gradu- ally subsiding marshes, or marshes and swamps subject to periodic overflow, the material itself being largely in the nature of sphagnous masses. By others it is thought that the plant material was first transported by running streams and laid down on the bottoms of deltas and lagoons ; that the coal beds are, in short, as true sedimen- tary deposits as the shales and sandstones with which they are associated. This last View would seemingly best account for the constant interlamination of the coaly and sandy or clayey material and the marked stratification of the coal itself. Moreover, it would explain the almost completely structureless nature of many coals, since calcium sulphate, one of the constituents of sea water, tends to decompose organic matter, reducing it to a pulp-like and at times almost mucilaginous condition. According to the amount of change that has taken place in the original plant material, the amount of volatile matter still retained by it, its hardness and burning qualities, several varieties of coal are recognized, which are described somewhat in detail below. The ger^ral subject, it may be said, is far too large to be satisfactorily disposed of here, and the reader is referred to the special works noted in the bibliography. Peat. This name is given to a material resulting from the accu- mulation of sphagnous mosses in bogs, and which has, as a rule, under- gone so slight modification that the plant fibers are still readily recognizable, though where the beds have reached a considerable thickness the lower portion may be reduced to a dense brownish- black mass somewhat resembling true coal. These deposits as exist- HYDROCARBON COMPOUNDS. 347 ing to-day are all of recent origin, and to be found only in humid and temperate or north temperate climates. They are developed to an enormous extent in Ireland, where they average, in some cases, twenty five feet in thickness. They are also abundant on the conti- nent of Europe and throughout the northern and eastern United States. In Ireland and on the Continent the material has been extensively used as fuel, in the first- named country largely in its native state, but in Germany after being made up into briquettes. 1 Cheapness of wood and coal in America has until recently caused peat to be largely disregarded, but recent events have turned attention toward it once more, and it seems probable that within the next few years numerous plants will be established for converting the crude material into a satisfactory form for fuel. In America the chief use of the material has thus far been as a fertilizer, a material for mulching. An impure variety containing a considerable quantity of silicious sand, and locally known as "muck," is thus used throughout New England. .According to J. E. Kehl, United States consul at Stettin, Germany, the manufacture of peat briquettes in that country is likely to become an industry of some importance. The peat fresh from the moor is cut and ground quite finely by machinery, dried by steam, and pressed into the desired form. The material thus prepared is said to be clean to handle, gives a good heat, and burns satisfactorily in both stoves and open grates. The peat briquettes retail at the rate of 8 for a cent, American money. 2 1 A new method of making charcoal from peat has been patented in England by Mr. Blundell and is to be tried in Italy, where there are large deposits of peat which can, it is claimed, be handled very cheaply. In this process the peat is first reduced to a fine paste and leaves the machine in a continuous thick tube 3 to 5 inches in diameter, and is then cut off in sticks and dried for three days on wooden supports and for a longer period in the air on wire netting. After twenty-five days the sticks become dry and hard and may be burned as fuel; but it is more profitable to convert these sticks into charcoal. This is accomplished in six hours in a retort, and 3 tons of peat make i ton of charcoal. Engineering and Mining Journal, LXV, February 26, 1898, p. 248. - United States Consular Reports, January, 1899, p. 99. THE NON-METALLIC MINERALS. Below are given the results of analyses on samples of peat from Prince Edward's Island. 1 Constituents. Hydro- scopic Water. Volatile Combusti- ble Matter. Fixed Carbon. Ash. Champlain peat 14.06 so. 60 22.2O 3.24 Hodges peat I7.o6 so. 72^ 2^.06 6.265 Indian Island peat. . . Black Bank peat. . . . 23.71 16.52 41.195 53-29 I9-835 22.48 15.26 7.71 Lignite or Brown Coal. This name is given to a brownish- black variety of coal characterized by a brilliant luster, conchoidal fracture, and brown streak. Such contain from 55 to 65 per cent of carbon, and burn easily, with a smoky flame, but are inferior to the true coals for heating purposes. They are also objectionable on account of the soot they create, and their rapid disintegration and general deterioration when exposed to the air. They occur in beds under conditions similar to the true coals, but are of more recent origin. The lignitic coals of the regions of the United States west of the Mississippi River are mainly of Laramie age, and often show easily recognizable traces of their organic origin, such as compressed and flattened stems and trunks of trees with traces of woody fiber. Jet is a resinous, coal-black variety of lignite sufficiently dense to be carved into small ornaments. According to Professor Phillips, it is simply a coniferous wood, and still shows the characteristic structure under the microscope. It has been known since early British times, having at first been found on the seashore at Whitby and other places. The largest piece on record was obtained from the North Bats, near Whitby. It weighed some 5,180 pounds and was valued at about $1,250. The material is now regularly mined both in the cliffs and inland, and is one of the most valuable prod- ucts of the Yorkshire coast. 2 1 Report on the Geological Structure and Mineral Resources of Prince Edward's Island, 1871. 2 Geology of England and Wales, p. 278. HYDROCARBON COMPOUNDS. 349 Bituminous Coals. Under this name are included a series of compact and brittle products in which no traces of organic remains are to be seen on casual inspection, but which under the microscope often show traces of woody fiber, spores of lycopods, etc. These coals are usually of a brown to black color, with a brown or gray- brown streak, breaking with a cubical or conchoidal fracture, and burning readily with a yellow, smoky flame. They contain from 35 to 75 per cent of fixed carbon, 1 8 to 60 per cent of volatile matter, from 2 to 20 per cent of water, and only too frequently show traces of sulphur, due to included iron pyrites. Several varieties of bitu- minous coals are recognized, the distinctions being based upon their manner of burning. Coking coals are so called from the facility with which they may be made to yield coke. Such give a yellow flame in burning and make a hot fire. Other varieties of apparently the same composition and general physical properties can not be made to yield coke, and are known as non- coking coals. Cannel coal has a very compact structure, breaks with a conchoidal fracture, has a dull luster, ignites easily, and burns with a yellow flame. It does not coke. Its chief characteristic is the large amount of volatile matter given off when heated, whereby it is rendered of particular- value for making gas. Before the discovery of petroleum it was used for the distilla- tion of oils. Below is given the composition of (I) a coking coal from the Connellsville Basin of Pennsylvania, and (II) a cannel coal from Kanawha County, West Virginia. Constituents. I. II. Water I. IOC Volatile matter 20 88=; ^8 oo Fixed carbon 7.7 cj. 23. so Ash Q.8cK 18. co Sulphur. . .. ............... 1-330 Total QQ 078 TOO OO Anthracite Coal. This is a deep-black, lustrous, hard and brittle variety, and represents the most highly metamorphosed variety of the coal series. Traces of organic nature are almost 35 THE NON-METALLIC MINERALS. entirely lacking in the matter of the anthracite itself, though impres- sions of ferns, lycopods, sigillaria, and other coal- forming plants are frequently associated with the beds in such a manner as to leave little doubt as to their origin. Anthracite is ignited with difficulty and burns with little flame, but makes a hot fire. Below is given the average composition of a coal from the Kohinoor Colliery, Shenandoah, Pennsylvania. 1 Water 3.163 Volatile matter 3'7*7 Fixed carbon 81.143 Sulphur 0.899 Ash 1 1.078 Total 100.00 Until recently it has been quite generally assumed that anthracite is but a bituminous coal from which a large portion of the volatile matter has been driven off by the heat and pressure incidental to mountain making or the intrusion of igneous rocks. Undoubtedly anthracite may be thus produced and in some cases has been thus produced, as in the Cerrillos coal field of New Mexico, where a bituminous coal containing some 30 per cent of volatile matter has been locally converted into anthracite through the intru- sion of a mass of an andesitic trachyte. Prof. J. J. Stevenson has, however, argued 2 that the difference between anthracite and the bituminous coals is due, not to metamor- phism through heat and pressure after being buried, but rather to the former having been longer exposed to the percolating action of water, whereby the volatile constituents were removed, prior to its final burial, and the consolidation of the inclosing rocks. Like the other coals, anthracite occurs in true beds, but is con- fined mostly to rocks of the Carboniferous Age. Thin seams of anthracite sometimes occur in Devonian and Silurian rocks, but 1 F. P. Dewey, Bulletin No. 42, United States National Museum, 1891, p. 231. 2 Bulletin Geological Society of America, VII, 1895, p. 525. HYDROCARBON COMPOUNDS. 35 1 which are too small to be of economic value. Rarely coals of more recent geological horizon have been formed locally, altered into anthracite by the heat of igneous rocks. Through a still further metamorphism, whereby it loses all its volatile constituents, coal passes over into graphite, and it is possible, though scarcely probable, that all graphite may have originated in this way. The principal anthracite coal regions of the United States are in eastern Pennsylvania. From here westward throughout the interior States to the front range of the Rocky Mountains the coals are all soft, bituminous coals. Those of the Rocky Mountain region proper are largely lignitic, passing into the bituminous varieties. (See Plate XXVI.) BIBLIOGRAPHY. The bibliography of coal, even though limited to the United States, would be enormous. In all cases reference should be made to the publications of the various State surveys, where such have existed. The few titles here given are of articles of general interest, and, as a rule, not relating to the coals of one particular locality alone. WALTER R. JOHNSON. A Report to the Navy Department of the United States on American Coals Applicable to Steam Navigation and to other purposes. Washington, D.C , 1844. RICHARD COWLING TAYLOR. Statistics of Coal. The Geographical and Geological Distribution of Mineral Combustibles or Fossil Fuel, etc. Philadelphia, 1848. J. LECONTE. Lectures on Coal. Report of the Smithsonian Institution, 1857, p. 119. T. H. LEAVITT. Peat as a Fuel. Second Edition. Boston, 1866, p. 168. Facts About Peat as an Article of Fuel. Third Edition. Boston, 1867, p. 316. E. W. HILGARD. Note on Lignite Beds and their Under Clays. American Journal of Science, VII, 1874, p. 208. LEO LESQUEREUX. On the Formation of Lignite Beds of the Rocky Mountain Region. American Journal of Science, VII, 1874, p. 29. J. S. NEWBERRY. On the Lignites and Plant Beds of Western America. American Journal of Science, VII, 1874, p. 399. JAMES MACFARLANE. Coal Regions of America. New York, 1875. MIALL GREEN, THORPE, RUCKER, and MARSHALL. Coal; Its History and Uses. Edited by Professor Thorpe. London, 1878, p. 363. 35 2 THE NON-METALLIC MINERALS. RAPHAEL PUMPELLY. Report on the Mining Industries of the United States, with special investigation into the Iron Resources of the Republic and into the Creta- ceous Coals of the Northwest. Tenth Census of the United States, XV, 1880. \V. IVISON MACADAM. Analyses of Coals from New Zealand and Labuan. Transactions of the Edinburgh Geological Society, IV, Pt. 2, p. 165, session 1881-82. J. S. NEWBERRY. On the Physical Conditions under which Coal was Formed. Science, I, March 2, 1883, p. 89. CHARLES A. ASHBURNER. The Classification and Composition of Pennsylvania An- thracites. Transactions of the American Institute of Mining Engineers, XIV, 1885, p. 706. LEO LESQUERETJX/ On the Vegetable Origin of Coal. Annual Report of the Geological Survey of Pennsylvania, 1885, p. 95. S. W. JOHNSON. Peat and its Uses as Fertilizer and Fuel. New York, 1886. GRAHAM MACFARLANE. Notes on American Cannel Coal. Transactions of the American Institute of Mining Engineers, XVIII, 1890. W. GALLOWAY. The South African Coal Field. Proceedings of the South Wales Institute of Engineers, No. 2, XVII, 1890, p. 67, LEVI W. MEYERS. L'Origine de la Houille. Revue de Quest. Scientifique Brussels, July, 1892, pp. 5-47. WILLIAM H. PAGE. The Carboniferous Age and -the Origin of Coal. Engineering and Mining Journal, LVI, 1893, p. 347. Note sur la formation des Terraines Houillers. Bulletin de la Societe Geologique de France, XXIV, 1896, p. 150. Making Coal of Bog Peat. The Iron Age, LXII, August 18, 1898, p. 3. 2. THE BITUMEN SERIES. Under this head are included a series of hydrocarbon compounds varying in physical properties from solid to gaseous and in color from coal-black through brown, greenish, red, and yellow to colorless. Unlike the members of the series already described, they are not the residual products of plant decomposition in situ, but are rather, in part at least, distillation products from deeply buried organic matter of both animal and vegetable origin. The members of the series differ so widely in their properties and uses that each must be dis- cussed independently. The grouping of the various compounds as given below is open to many objections from a strictly scientific stand- HYDROCARBON COMPOUNDS. 353 point, but, all things considered, it seems best suited for the present purposes. 1 tq Bituminous. Resinous Cerous (waxy). TABULAR CLASSIFICATION OF HYDROCARBONS.- 1 Gaseous Marsh gas (Natural gas). Fluidal Petroleum (Naphtha). ( Pittasphalt (Maltha). Viscous and semisolid -I Mineral tar. ( Asphalt. TM x- ( Elaterite. Elastlc \Wurtzillite. !Albertite. Grahamite. Uintaite. { Succinite. I Copalite. ' 1 Torbanite. Ambrite. Ozokerite. Hatchettite. TABULAR CLASSIFICATION OR GROUPING OF NATURAL AND ARTIFICIAL BITUMINOUS COMPOUNDS. Mixed with limestone, " asphal- j Seyssel, Val de Travers, Lobsan, Illi- ( nois, and other localities. ' as- j California, Kentucky, Utah, and other \ localities. ' ' Bituminous silica." tic limestone. Mixed with silica and sand, phaltic sand." Mixed with earthy matter, phaltic earth." -r,.^ . .." ( Canada, California, Kentucky, Virginia. Bituminous schists \ ^ Q ' ther localiti ' es . 'as- j Trinidad) Cuba, California, Utah. Fluid.. Viscous. Thick oils from the distillation of petro- leum . ' ' Residuum . ' ' Gas-tar. Pitch. { Refined Trinidad asphaltic earth. Mas- q ,. , J tic of asphaltite. I Gritted asphaltic mastic. Paving com- l pounds. 1 See article What is Bitumen, by S. F. Peckham, Journal of the Franklin Insti- tute, CXL, 1895, pp. 370 to 383. 3 W. P. Blake, Transactions of the American Institute of Mining Engineers, XVIII, 1890, p. 582. 354 THE NON-METALLIC MINERALS. Important natural bitumens. Asphaltum almost pure. Still another arrangement is that given below : TABLE OF OCCURRENCE OF IMPORTANT NATURAL BITUMEN. 1 Natural gas Ohio, Pennsylvania, California, etc., in the United States; Russia, France, etc. Natural naphtha Found in petroleum districts (of little value, superseded by artificial naphtha, from crude petroleum). Petroleum Pennsylvania, Ohio, Wyoming, California, etc., in United States; Russia, etc. (con- sult books on petroleum). Maltha California, Wyoming, Alabama, Utah, Col- orado, Kentticky, New Mexico, Ohio, Texas, Indian Territory, etc.; Russia, France, Germany, etc. North America.. Utah, California, Texas, etc. Central America. Cuba, Mexico, etc. South America . . Trinidad, Venezuela, Peru, Colombia, etc. Europe Caucasia, Syran-on-the- Volga, Germany, France, Italy, Austria, etc. Asia Hit on the Euphrates, Asia Minor, Palestine, etc. Africa Oran in Egypt; probably other places. North America. .West Virginia, Kentucky, Texas, Wyoming, Utah, Colorado, California, Indian Territory, Mon- tana, New Mexico. Central America.Mexico, Cuba, etc. South America. .Trinidad (largest supply, most used), Venezuela, Asphaltic Peru, Colombia, etc compounds. | Europe Germany, Switzerland, France, Italy,' Sicily, Russia, Austria, Spain, etc. Asia Asia Minor, Palestine, Bagdad, and probably in China, Africa Egypt, and probably else- where in Africa. Origin. Of the many views, mainly theoretical, that have been put forward to account for the origin of bituminous compounds, but two need be noted in detail here. Interested readers are referred to the bibliography given on page 385, and particularly to the works of Asphaltum. 1 J. W. Howard, as quoted by S. P. Sadtler, Journal of the Franklin Institute, CXL, 1895, p. 200. HYDROCARBON COMPOUNDS. 355 Peckham, Orton, and Redwood. Prof. Edward Grton, after an ex- haustive consideration of the occurrence of petroleum, natural gas,, and asphalt in Kentucky, 1 gives the following precise summary: "i. Petroleum is derived from organic matter. " 2. Petroleum of the Pennsylvania type is derived from the organic matter of bituminous shales, and is probably of vegetable origin. "3. Petroleum of the Canadian type is derived from limestones,, and is probably of animal origin. "4. Petroleum has been produced at normal rock temperatures, (in American fields), and is not a production of destructive distilla- tion of bituminous shales. "5. The stock of petroleum in the rocks is already practically complete." Hofer 2 regards petroleum as of animal origin only, and ad- vances the arguments given below in support of his theory: "i. Oil is found in strata containing animal, but little or no plant remains. This is the case in the Carpathians, and in the limestone examined in Canada and the United States by Sterry Hunt. " 2. The shales from which oil and paraffin were obtained in the Liassic oil shales of Swabia and of Steirdorf, in Styria, contained animal, but no vegetable remains. Other shales, as, for instance, the copper shales of Mansfield, where the bitumen amounts to 22 per cent, are rich in animal remains and practically free from vege- table remains. "3. Rocks which are rich in vegetable remains are generally not bituminous. " 4. Substances resembling petroleum are produced by the decom- position of animal remains. 3 1 Report on the Occurrence of Petroleum, etc., in Western Kentucky. Geological Survey of Kentucky, John R. Proctor, director, 1891. 2 As quoted by Redwood, I, p. 238. 8 Dr. Engler, as quoted by Redwood, obtained by distillation of menhaden oil, among other products, a substance remarkably like petroleum, and a lighting oil indistinguishable from commercial kerosene. 356 THE NON-METALLIC MINERALS. "5. Fraas observed exudations of petroleum from a coral reef on the shores of the Red Sea, where it could be only of animal origin." The relationship which exists between the solid or viscous bitu- men and the fluidal petroleum has not in all cases been satisfactorily worked out, though Peckham has shown 1 that in California at least there are almost infinite gradations from one extreme to the other. In Ventura County, for instance, the petroleum is held, primarily, in strata of shale, from which it issues as petroleum or maltha, accord- ingly as the shales have been brought into contact with the atmos- phere, the asphaltum being produced by a still further exposure to the atmosphere after the bitumen has reached the surface. This relation- ship between the more fluidal and viscous varieties is shown in Fig. 26, copied from Prof. Peckham's paper above referred to, and which represents a section across a portion of Sulphur Mountain between the Hayward Petroleum Company's tunnels in Wheeler Canyon, and the Big Spring Plateau on the Ojai ranch. In this section it will be noted that the mountain is formed of a synclinal fold of shale, the strata dipping inward on both sides and coming to the surface almost vertically on the right, and more nearly horizontally on the left (the south). The tunnels are driven into the nearly vertical face of the mountain and the oil-bearing rock is protected by some 700 or 800 feet of overlying shales. The oil obtained is the lightest thus far found in southern California. On the other hand, the material which exudes on the north side, when the shales are upturned at such an angle -as to give free access to atmospheric agencies, is in the form of maltha, or mineral tar, and so viscous, in December, 1865, that it could be gathered and rolled into balls like dough. The relationship between petroleum and natural gas is scarcely better defined. That the gas can be derived from petroleum is undoubted, and indeed the latter apparently never occurs free from gas. But on the other hand, at Professor Orton states, the gas often originates under many conditions in which petroleum does not occur. The formation of marsh gas from decomposing plant re- mains on the bottom of stagnant pools, and its presence in coal mines would show with seeming conclusiveness that a part, at least. 1 See report of the Tenth Census, p. 68. HYDROCARBON COMPOUNDS. 357 358 THE NON-METALLIC MINERALS. of the gas is formed quite independently of petroleum. It would seem on the whole most probable that no one theory was universally applicable to all cases. Marsh Gas; Natural Gas. This is a colorless and odorless gas arising from the decomposition of organic matter protected from the oxidizing influence of atmospheric air. By itself it burns quietly, \vith a slightly luminous flame, but when mixed with air it forms a dangerous explosive. It is this gas which forms the dreaded fire- damp of the miners. In small quantities this gas may be found and collected, if desired, from the bottom of shallow pools and stagnant bodies of water by merely disturbing the decomposing plant matter at the bottom, when the bubbles of the gas will rise to the top. Under this head may properly be considered the so-called natural gas, which has of late years become of so much importance from an economic standpoint. This gas is, however, by no means a simple compound, but a variable admixture of several gases, samples from different wells showing considerable variation in composition, as well as those from the same well collected at different periods. This last is shown by the seven analyses following, and which may serve well to illus- trate the average composition, though in some instances the per- centage of marsh gas has been found greater. 1 Constituents. I. II. III. IV. V. VI. VII. 1.89 1.64 1.74 2.35 1.86 1.42 i. 20 92.84 93-35 93.85 92.67 93.07 94.1.6 93,58 Olefiant gas O.2O O.Xs O.2O 0.25 0.49 O."?O O.I? Carbonic oxide ..... O.<^ 0.41 0.44 0.45 0.73 o.^ o..6o Carbonic acid . ..... O.2O 0.2^ O.23 O.2f? 0.26 0.29 0.30 O xv sen 0.3^ CM9 O-35 0.35 0.42 O.51 Nitrogen . ...... 3.82 3.41 2.98 ^53 3.02 2 80 3-42 Sulphuretted hydrogen.. 0.15 0.20 O.2I 0.15 0.15 0.18 O.2O Total IOO.OO IOO.OO IOO.OO IOO.OO IOO.OO 100.00 IOO.OO I, Fostoria, Ohio; II, Findlay, Ohio; III, St. Marys, Ohio; IV, Muncie, Indiana; V, Anderson, Indiana; VI, Kokomo, Indiana; VII, Marion, Indiana. Natural gas in quantities to be of economic importance is neces- sarily limited to rocks of no particular horizon. It is not, however, 1 From Orton's Report on Petroleum, Natural Gas, and Asphalt in Kentucky, pp. 108-110. HYDROCARBON COMPOUNDS. 359 indigenous to the rocks in which it is now found, but occurs in an overlying more or less porous sand or lime rock into which it has been forced by hydrostatic pressure. The first necessary condition for the presence of gas in any locality may indeed be said to depend upon the .existence of such a porous rock as may serve as a reservoir to hold it, and also the presence of an impervious overlying strata to prevent its escape. In Pennsylvania the reservoir rock is a sand- stone of Carboniferous or Devonian age; in Ohio and Indiana a cavernous dolomitic limestone of Silurian (Trenton) age. Petroleum. This is a name given to a complex hydrocarbon compound, liquid at ordinary temperatures, though varying greatly in viscosity, of a black, brown, greenish, or more rarely red or yellow color, and of extremely disagreeable odor. Its specific gravity varies from 0.6 to 0.9. Through becoming more and more viscous, the mat erial passes into the solid and semisolid forms asphalt and maltha. Chemically it is considered as a mixture of the various hydrocarbons included in the marsh gas, ethyline, and paraffin series. An ultimate analysis of several samples, as given by the reports of the Tenth Census of the United States (1880), showed the following percentages of the three essential constituents : Locality. Hydrogen. Carbon. Nitrogen. West Virginia I7.-JCQ 85.200 O.CA jVtecca Ohio I 3 O7I 86 316 California. II Sio 86 Q34. w*J I IOO Petroleum is limited to no particular geological horizon, but is found in rocks of all ages, from the lower Silurian to the most recent, its existence in quantities sufficient for economic purposes being dependent upon local conditions for its generation and subsequent preservation. Inasmuch as its accumulation in large quantities necessitates a rock of porous nature to act as a reservoir, the petro- leum-bearing rocks are mostly sandstones, though not uniformly so. Petroleums are found in California and Texas in Tertiary sands ; in Colorado in the Cretaceous ; in West Virginia both above and below the Crinoidal (Carboniferous) limestones; in Pennsylvania in the Mountain sands (Lower Carboniferous) and the Venango sands 3 6 THE NON-METALLIC MINERALS. (Devonian); in Canada in the Corniferous (Lower Devonian) lime- stones; in Kentucky in the Hudson River shales (Lower Silurian), and in Ohio in the Trenton limestone. In some instances petroleum oozes naturally from the ground, forming at times a thin layer on the surface of pools of water, whence in times past it has been gathered and used for chemical and medic- inal purposes. The so-called "Seneca oil" thus used some fifty or sixty years ago was obtained from a spring in Cuba, Allegany County, in New York. The immense supply now demanded for com- mercial purposes is, however, obtained altogether from artificial wells of varying depths, and which are in some cases self-flowing, while in others the oil is raised by means of pumps. Wells of from 500 to 1,500 feet in depth are of common occurrence, while those upwards of 2,000 feet are not rare. The principal sources of petroleum are in the United States New York, Pennsylvania, and Ohio, with smaller fields in West Virginia, Kentucky, Tennessee, Indiana, Texas, Colorado, and California. The chief foreign source is the Baku region on the Caspian Sea, and Galicia, in Austria. Uses of petroleum. The early uses of petroleum in America seem to have been for medicinal purposes only. The oil as pumped from the wells has but a limited application in its crude condition excepting as a fuel, and owes its great value to the large and varied series of derivatives which it yields. A discussion of the methods employed in obtaining these derivatives belongs properly to the department of chemical technology, and can not be dwelt upon here. It must suffice for present purposes to say that the treatment as ordinarily carried out at present involves a process of destructive distillation whereby the crude material, heated under pressure, is resolved into a variety of products of different densities, and varying from gaseous through liquid to solid forms. Prominent among these derivative may be mentioned, aside from the gaseous compounds, rhigolene, gasoline, naphtha, benzine, kerosene, various lubricating oils, paraffin, and the soild residues (coke, etc.). Various phar- maceutical compounds are prepared from petroleum products, many of which are well known to the public, as vaseline, cosmoline, etc. It is also used as a basis for ointments and in soaps. The accompanying map (Plate XXV) from the reports of the P2TG&LAK& V/CINITY. PLATE XXVII. HYDROCARBON COMPOUNDS. 3 6r Tenth Census will serve to show the distribution of petroleum and allied bituminous compounds in the United States. For full and detailed information relative to the petroleum industry of the world the reader is referred to the works mentioned in the Bibliography, that of Boverton Redwood being the most systematic and complete. Asphaltum; Mineral Pitch. These are names given to what are rather indefinite admixtures of various hydrocarbons, in part oxygenated and which, for the most part solid or at least highly viscous at ordinary temperatures, pass by insensible gradations into pittasphalt or mineral tar, and these in turn into the petroleums. They are characterized by a black or brownish-black color, pitchy luster, and bituminous odor. The solid forms melt ordinarily at a temperature of from 90 to 100 F., and burn readily with a bright flame, giving off dense fumes of a tarry odor. The fluidal varieties become solid on exposure to the atmosphere, owing to evaporation of the more volatile portions. The nature of the material, its mode of occurrence, and indeed the uses to which it can be put, vary to such an extent with each indi- vidual occurrence that a few only of what are the most noted or best known can here be mentioned. Island oj Trinidad. The occurrence on this island of an immense body of asphaltic material has been known for upwards of a hundred years, and numerous, often widely differing, accounts of it are to be found in literature. The latest and perhaps most satisfactory, when everything is taken into consideration, is that of S. F. Peckham. 1 The deposit, which covers an area of nearly 100 acres, is situated at an elevation of 138 feet above the level of the sea (see map, Plate XXVII), and on superficial examination has an appearance such as has caused it to be known by the not wholly inappropriate name of the Pitch Lake of Trinidad. The depth of the deposit, in various parts, has been estimated at from 1 8 to 78 feet. According to the early accounts, the pitch at the margin of t'he lake is cold and hard, becom- ing gradually warmer and more viscous toward the center, until a point is reached where it is too soft to support the weight of a man and so warm as to be described as "boiling." However, this may 1 American Journal of Science, L, 1895, pp. 33-51. 362 THE NON-METALLIC MINERALS. have been years ago; the material is now sufficiently firm over the entire surface to support men and teams for a time sufficient for load- ing. The deposit is regarded as a mud volcano, the bitumen being still brought up intermixed with water and mud, the numerous small islands which occupy the surface of the lake being but masses of earthy matter floating upon or buoyed up by the pitch. Though the deposit has been worked for many years and thousands of tons of asphalt removed, no appreciable impression has as yet been pro- duced upon the amount of material available. The crude material has the following composition and physical characteristics : * Specific gravity, 1.28; hardness at 70 F., 2.5 to 3 of Dana's scale; color, chocolate-brown; composition: Bitumen 39-83 Earthy matter 33-99 Vegetable matter , . 9.31 Water 16.87 Total 100.00 Cuba. Asphalt in some of its varieties occurs in nearly every one of the Cuban provinces and in several instances in sufficient abun- dance to be of economic importance. In all instances thus far de- scribed, 2 the material occurs in veins or pockets, or exudes in the form of springs, usually in serpentinous rocks or limestones. As long ago as 1837 R. C. Taylor described 3 a deposit of asphalt at that time regarded as bituminous coal occurring some 10 miles east of Havana as occupying an irregularly branching fis- sure from i. to 9 feet in width in a soft clay rock, which is now known to be a decomposed eruptive. The appearance of the vein, in vertical section, is shown in Fig. 27, the bottom of the cut representing a distance from the surface of 30 feet. The asphalt itself was described as of a jet-black color, resplendent luster, 1 F. V. Greene. Asphalt and Its Uses. Transactions of the American Institute of Mining Engineers., 17, 1888-89, p. 355. 2 See Report on Geological Reconnoissance of Cuba, 1901. 3 London and Edinburgh Philosophical Magazine and Journal of Science, X, 1837, p. 161. HYDROCARBON COMPOUNDS. 363 conchoidal fracture, and with a specific gravity varying from 1.42 to 1.97. An analysis by T. G. Clemson showed 63 per cent volatile matter, 34-97 per cent carbon, and 2.03 per cent ash. Several interesting submarine deposits exist in Cardinos Bay, which may be mentioned on ac- count of the unique methods of mining. These have been de- scribed by J. L. Hance. The 4Feetl country rock is a limestone and the asphalt of a brilliant black color and about as friable as cannel coal. In mining a lighter is anchored directly over the body of asphalt and a long, pointed iron bar raised by a winch, on board, dropped upon it, the weight of the bar being sufficient to break away pieces of the asphalt, which are then collected by divers and sent to the sur- face in nets. The material has been utilized in making varnish, and formerly brought a high price. A large deposit of an inferior grade, and used mainly for roofing is situated near Diana Key, 15 miles from the city of Cardenas, and a massive bed, some 12 feet in thickness, near Villa Clara. Material from this last source has, during years past, been used for making the illuminating gas used in the city. Baron H. Eggers has described 1 the two groups of asphalt deposits near the Gulf of Maracaibo, South America, which are perhaps sufficiently distinctive to merit attention. One, the El Menito deposit, is in the form of a rounded hill composed of reddish stony soil covered with scanty grass. Over its summit are scattered a 9Teet > FIG. 27. Asphalt vein, Cuba. [After R. C. Taylor.] 1 Scottish Geographical Magazine, XIII, 1897, p. 209. An abstract of original paper in the Deutsche Geographische Blatter, XIX, Pt. 4. 364 THE NON-METALLIC MINERALS. number of small truncated cones about 2 feet high, with round, crater-like openings, from which the asphalt, or pitch, flows in a black, viscous stream down to the foot of the hill, where it collects and forms pools or small lakes. The outflowing asphalt is quite cold, and hardens in the course of a few days. The Mene Grande deposit is quite similar, but much larger, and has been calculated to yield some 2 tons a day. Other deposits occur in the region. Sandstones and limestones are sometimes so impregnated with bituminous matter that they may be used as sources of the material by refining processes or for the direct manufacture of pavements by simply crushing. Such are the so-called bituminous or asphaltic sand rocks and limestones of Kentucky, Texas, Indian Territory, Utah, Colorado, California, Wyoming, and other States, and of Canada and Spain. According to G. H. Stone, 1 the asphaltic sandrock of western Colorado and eastern Utah consists of grains of sand which are in contact with one another, the spaces between the grains being filled with asphalt, the proportioned amount of which varies up to 15 per cent by weight, or 27 per cent by volume. The thickest stratum of fully charged rock in the region described was nearly 40 feet in thick- ness, though usually the strata of high-grade material are not more than 4 to 10 feet thick and alternate with others which are quite poor or barren, so that the amount of "pay rock" is often grossly exaggerated. Shales and marls may often be so highly charged with bituminous matter as to be nearly or quite black, and even approach cannel coal in composition, though much richer in ash. Those of Colorado and Utah, according to Stone, contain but from 10 to 20 per cent of carbonaceous matter, though burning readily with a bright flame. They are of Tertiary Age. Asphaltic sands and sandrocks are of common occurrence in the immediate vicinity of the Coast Range in California from Point Arena, north of San Francisco, to the southernmost part of the State. 2 The deposits occur almost inva- riably as sands and shales, belonging to the Neocene formations, 1 American Journal of Science, XLII, 1891, p. 148. 2 See Thirteenth Annual Report State Mineralogist of California 1896, also Twenty-second Annual Report, U. S. G. S., 1900-1901, Pt. I, pp. 209-464. C P < n n <-t X c .' . N o s* PLATE XXIX. Quarry of Bituminous Sandstone, Indian Territory. [U. S. Geological Survey.] HYDROCARBON COMPOUNDS. 365 impregnated with varying amounts of bitumen, though rarely exceed- ing 15 to 20 per cent by weight. The material is mined from open cuts and rarely from shafts, and is utilized in large part for street- paving purposes. In the region south of the Canadian River, in Indian Territory, asphalt and asphalt lime and sandstones occur over extensive areas, the more important being in what are known as the Buckhorn and Brunswick districts. The rocks of the regions are wholly sedimen- tary, and the bituminous members belong mainly to the Lower Silurian (Ordovician), Coal Measure, and Cretaceous formations. In the eastern part of the territory, the Ten Mile district, is found a very pure, brittle material somewhat resembling albertite (p. 368) and for which the name impsonite has been suggested. 1 It contains some 86 per cent of carbon and 8 per cent of hydrogen. The material is found in a vein in greenish gray shales, having a trend of 15 N. to 20 E, and pitching 45 to 65 to the eastward. At the Ralston quarry in the Buckhorn district the rock is a massive Ordovician sandstone some 15 feet in thickness overlaid by some 75 to 100 feet of conglomerate. The bitumen contents amounts to between 10 and 12 per cent. (See Plate XXIX.) At the quarry of the Gilsonite Paving and Roofing Company in this same district, the bitumen is in strata referred to the Lower Coal Meas- ures. (See section, Fig. 28.) The bitumen-bearing member here (No. 9 in section) is a hard massive limestone, the upper portion of which is highly fossiliferous, and the lower sometimes conglomer- atic. It yields on an average some 14 per cent, of bitumen. Uses. The uses of the common type of material such as is known simply as asphalt are quite varied. The walls of Babylon are stated to have been cemented with it, and doubtless it was so- used in other ancient cities. It was also, as at present, used for making vessels water-tight. At the present day the refined asphalts are used as a varnish or paint, as an insulating material, for waterproofing, as a cement in ordinary construction, and as a cement in roofing and paving compounds. For these purposes it is first tempered with 1 After the Impson Valley, where it occurs. See Eldridge's paper, Twenty-second Annual Report, U. S. G. S. 366 THE NON-METALLIC MINERALS. some form of oil, the kind and amount used depending on the pur- poses to which it is to be applied. A mixture of asphalt and sand forms the ordinary concrete for sidewalks and basement floors. The most extensive use of asphaltic compounds is at present for street pavements, the material for this purpose being mixed with FIG. 28. Section across quarry of Gilsonite Paving and Roofing Company, showing bituminous limestone and associated strata. [U. S. Geological Survey.] i and 2, conglomerate; 3, shales; 4, conglomerate; 5, quartzite, 6, limestone, bi- tuminous; 7, limestone, somewhat bituminous; 8, calcareous with wood fiber and coal; 9, limestone averaging 14 per cent bitumen; 10, shale; u, conglomerate; 12, bituminous shale. fine sand and sometimes powdered limestone. 1 The asphaltic sands, sandstones, and limestones are sometimes so evenly impregnated with bituminous matter that they may be crushed and applied directly to the roadbed. The uses to which are put the higher grades of asphaltic compounds, such as are designated by special names, are given further on. Manjak. The local name of manjak is applied to a variety of bitumen somewhat resembling uintaite, occurring on the island of Barbados, in the West Indies. The material is a very pure hydro- carbon of a black color, but yielding a brown powder, high luster, and with a bright conchoidal fracture. It is brittle, and so friable that it can be ground to powder between the thumb and fingers. It occurs in seams or veins, varying from one-fourth of an inch to 30 feet in thickness, cutting the country rock, which is an argillite or shale, at all angles with the horizon and with a general NNE. strike. In 1 Asphalt and its Uses, Transactions of the American Institute of Mining Engineers, XVII, 1889, p. 335. HYDROCARBON COMPOUNDS. 367 places the bituminous matter has saturated the entire rock in the neighborhood of the veins, producing a shale from which as much as 37 gallons a ton of petroleum have been obtained by destructive distillation. Thus far the greatest development is along a vein 200 feet in length, 100 feet in depth, and from 8 to 9 feet in width. One vein, which has been explored to a depth of 200 feet, is stated to have dwindled down to a width of 6 feet, though 30 feet wide at the surface. 1 Uses. Like gilsonite, the material is used for making varnishes, insulating electric wires, etc., bringing the price of this mineral, from $5 to $10 a ton, according to quality and freedom from impur- ities. Elaterite; Mineral Caoutchouc. This is the name given to a soft and elastic variety of bitumen much resembling pure india- rubber. It is easily compressible in the ringers, to which it adheres slightly, of a brownish color, and of a specific gravity varying from 0.905 to i. oo. It has been described from mines in Derbyshire and elsewhere in England, but so far as the writer is aware is- of no com- mercial value. Its composition, so far as determined, is carbon, 85.47 per cent; hydrogen, 13.28 per cent. Wurtzillite. The name wurtzillite has been given by Prof. W. P. Blake to a hydrocarbon very similar in appearance to the uintaite (described on page 371), but differing in physical and chemical prop- erties. It is a fine black solid, amorphous in structure, brittle when cold, breaking with a conchoidal fracture, but when warm tough and elastic, its elasticity being best compared with that of mica. If bent too quickly it snaps like glass. It cuts like horn, has a hardness between 2 and 3, a specific gravity of 1.03, gives a brown streak, and in very thin flakes, shows a garnet-red color. It does not fuse or melt in boiling water, but becomes softer and more elastic; in the flame of a candle it melts and takes fire, burning with a bright luminous flame, giving off gas and a strong bituminous odor. It is not soluble in alcohol, and but sparingly so in ether, in both of which respects it differs from elaterite. In the United States it occurs near 1 W. Merivale, Engineering and Mining Journal, LXVI, 1898, p. 790; also the Mineral Industry, VI, 1897, p. 54. 3 68 THE NON-METALLIC MINERALS. Scofield, Carbon County, and in the Uinta Mountains of Wasatch County, Utah. Albertite. This is a brilliant jet-black bitumen compound breaking with a lustrous, conchoidal fracture, having a hardness of between i and 2 of Dana's scale, a specific gravity of 1.097, black streak, and showing a brown color or very thin edge. In the flame of a lamp it shows signs of incipient fusion, intumesces somewhat, and emits jets of gas, giving off a bituminous odor; when rubbed it becomes electric. According to Dana it softens slightly in boiling water, is only a trace soluble in alcohol, 4 per cent in ether, and some 3 per cent soluble in turpentine. The following is the composition as given by Wetherill: Carbon, 86.04 P er cent ; hydrogen, 8.96 per cent; oxygen, 1.977 per cent; nitrogen, 2.93 per cent; ash, o.io per cent. Dr. Antisell made the following comparative tests to show the relative richness of the material in volatile matter: Constituents. Cannel Coal. South American Asphalt. Lake Asphalt. Albertite. Volatile matter SO. 52 7O. I? 71.67 CQ 88 Coke ~> J 47.60 20.8? 28.04 7Q.CQ Ash I.7Q O.2Q O.C7 Total IOO.OO IOO.OO IOO.OO 100 oo The mineral is described 1 as occurring in "true cutting veins" in shale of Lower Carboniferous Age in Hillsborough County, New Brunswick. The shales themselves contain a large amount of car- bonaceous matter and by distillation have been made to yield 30 gallons to the ton of refined illuminating oil. They contain immense numbers of fossil fish and are mostly inflammable. The veins vary from a fraction of an inch to 12 feet in width with a general N. 65 east course, sometimes vertical and sometimes inclined northwest- ward from 75 to 80. They enlarge and contract very irregularly, but in general increase in thickness as followed downward. Hitch- 1 American Journal of Science, XXXIX, 1865, p. 267; see also Dawson's Acadian Geology, 3d ed., pp. 231-241. HYDROCARBON COMPOUNDS. 369 cock regards the veins as having been rilled by the injection of the material in a liquid state and being subsequently indurated. Uses. This vein seems to have been discovered about 1840 by Dr. Abraham Gesner, who, in 1850, took out a patent in the United States for the manufacture of illuminating gas from this and other asphalts. 1 A company was organized and for some years active mining operations were carried on, but have been discontinued since the discovery of petroleum. Grahamite. Grahamite is a hydrocarbon compound closely related to albertite, but differing physically in having a duller luster and more coke-like aspect. It has been described by Dr. Henry Wurtz as occurring in shrinkage fissures whose course is N. 76 to So E. in Carboniferous shales and sandstones, on a branch of Hughes River, Ritchie County, West Virginia. It is completely soluble in chloroform and carbon disulphide, nearly so in turpentine, and par- tially so in naphtha and benzine, but not at all in alcohol. Melts somewhat imperfectly, beginning to smoke and soften like coking coal at a temperature of about 400 F. As occurring in the vein the material shows four distinct, though somewhat irregular, divisional planes, having a general parallelism with the walls. Next to the walls the structure of the mineral is coarsely granular, with an irregularly cuboidal jointed cleavage, very lustrous on the cleavage surfaces. The material in immediate con- tact with the walls usually adheres thereto very tenaciously, as if fused fast to the granular sandstone. The general aspect of the mass has led to the conclusion that the vein here is a fissure which has been filled by an exudation, in a pasty condition, of a resinoid substance derived from or formed by some organic matter contained in deep-seated strata intersected by the fissure or dike. The density of a mass of the mineral was found to be 1.145. The horizontal extent of visible outcrop actually measured was 530 fathoms, which thinned out at east end to 30 inches and at west 1 Review of reports on the Geological Relations, etc., of the coal of the Albert Coal Mining Company, situated in Hillsborough, Albert County, New Brunswick, as written and compiled by Charles T. Jackson, M.D., a Fellow of the Geological Society of London, etc., New York, 1852. 37 THE NON-METALLIC MINERALS'. end to 8 inches; but as these points were at least 70 to 80 fathoms vertically higher than the bottom of the ravine, the width (averaging about 50 inches) at the latter depth points to a rapid widening of the fissure in descent. 1 J. P. Kimball has described 2 a deposit of similar material on the west bank of the Capadero- River in the Huasteca, Vera Cruz, Mexico. The country rock is a fossiliferous Tertiary shale overlaid by conglomerate. The grahamite occurs in a fissure some 34 inches in thickness terminating in an " overflow" some 6J feet in maximum thickness, thinning away at the edges, 'but the full extent of which was not determined. The evidence showed that the fissure had been filled by material oozing up from below and spreading out upon the surface prior to the deposition of the overlying gravel. The strike of the fissure was nearly north and south. The material is more uniformly lustrous than that from Ritchie County, and of a greater coherence, though none the less distinctly cleaved and jointed. An analysis of a sample from the Cristo mine, as given, yielded results as follows: Specific gravity 1.156 Volatile matter: Illuminating gas 63.32 Sulphur 0.46 Water 0.36 64.14 XM * _ .__.. Coke: Fixed carbon 3 1.63 Sulphur 0.37 Ash 5.86 37-36 100.00 Carbonite or Natural Coke is the name given to a peculiar hydrocarbon compound occurring in the form of beds like bitumin- 1 Proceedings of the American Association for the Advancement of Science, XVIII, 1869, pp. 125-128. * American Journal of Science, XII, 1876, p 277. HYDROCARBON COMPOUNDS. 371 ous coal, in Chesterfield County, Virginia, and having a dull black and, for the most part, lusterless aspect, somewhat resembling coke. An analysis by Wurtz 1 yielded the following : Per cent. Coke 84.57 Volatile combustible matter *5-43 Other analyses by Dr. T. M. Drown 2 on two portions, the one dull and lusterless and the other lustrous, yielded: Constituents. Dull Portion. Lustrous Portion. Specific gravity I 37^ I 3?O Loss at 100 C. 2 OO O 60 Volatile matter I % 4.7 1 1 IO Ash 3 .20 6.68 7Q.-J-? Si.ca IOO.OO 4.08 IOO.OO i. 60 The material occurs interbedded with shales much like ordinary bituminous coal, there being, according to Raymond, three distinct beds varying from i foot 9 inches to 9 feet in thickness, interstratified with the shales, the lowermost bed of 9 feet thickness being under- laid by fire clay. The origin of the material is in doubt, the earlier writers regarding it as a bituminous coal coked by the heat of intru- sive rocks. Later writers throw doubt upon this by stating that there are in the vicinity no intrusives of such size as to warrant any such assumption. Uses. The material is said to burn without smoke or soot, like anthracite, and to have been used for domestic purposes. Uintaite; Gilsonite. This is a black, brilliant, and lustrous variety of bitumen, giving a dark-brown streak, breaking with a beau- tiful conchoidal fracture, and having a hardness of 2 to 2.5 and a specific gravity of 1.065 to I -7- If fuses readily in the flame of a candle, is plastic but not sticky while warm, and unless highly 1 Transactions of the American Institute of Mining Engineers, III, 1875, p. 456. * Idem, XI 1883, p. 448 37 2 THE NON-METALLIC MINERALS. heated will not adhere to cold paper. Its deportment is stated to be much like that of sealing wax or shellac. Like albertite and gra- hamite it dissolves in turpentine and is not soluble in alcohol. It is a nonconductor of electricity, but like albertite becomes electric by friction. Its composition as given is: Carbon, 80.88 per cent; hydrogen, 9.76 per cent; nitrogen, 3.30 per cent; oxygen, 6.05 per cent, and has, o.oi per cent. The name uintaite was given this substance by W. P. Blake in 1885, after the Uinta Mountains, where it was first found. It is also known under the trade name of gilsonite, after S. H. Gilson. Occurrence. According to George H. Eldridge 1 the gilsonite deposits of Utah occur filling a series of essentially vertical fissures in Tertiary sandstones lying within the Uncompahgre Indian Reser- vation, or in its immediate vicinity. The fissures have smooth, regular walls, and vary in width from the sixteenth of an inch to 1 8 feet, and in length from a few hundreds yards to 8 or 10 miles. The larger veins are somewhat scattered, one lying about 3! miles east of Fort Duchesne, a second in the region of the Upper Evacuation Creek, and the three others of most importance in the vicinity of the White River and the Colorado-Utah line. Besides these there is a 14- inch vein crossing the western boundary of the reservation near the fortieth parallel; another about equal size about 6 miles southeast of the junction of the Green and White rivers; a third in the gulch 4 or 5 miles north of Ouray Agency, west of the Duchesne River, and a number from one-sixteenth of an inch to a foot in thickness in an area about 10 miles wide, extending from Willow Creek eastward for 25 miles along both sides of the Green and White rivers. The veins are sometimes slightly faulted, and often pinch out to mere feather edges. The filling material is quite structureless excepting where, as near the surface, it has been ex- posed to the atmospheric influences, where it shows a fine pencillate or columnar structure at right angles to the walls. The walls of the veins are impregnated with the gilsonite for a distance of several inches, but all indications point to the veins themselves having been filled, not by lateral impregnation, but by injection from below. 'Seventeenth Annual Report U. S. Geological Survey, 1895-96, Pt. I, p. 915. HYDROCARBON COMPOUNDS. 373 The mining of uintaite is conducted in the ordinary manner by means of shafts and tunnels. The work is, however, attended with considerable difficulty and some danger, owing to the fine dust arising from it. This penetrates the skin and lungs, and is a source of great annoyance, and moreover becomes highly explosive when mixed with atmospheric air. Uses. The principal use of uintaite thus far has been in the manufacture of varnishes for ironwork and baking japans. It is not well adapted for coach varnishes. It has been also used for mixing with asphaltic limestone for paving material. Other pos- sible uses suggested are as below: For preventing electrolytic action on iron plates of ship bottoms; for coating barbed- wire fencing, etc.; for coating sea walls of brick or masonry; for covering paving brick; for acid proof lining for chemical tanks ; for roofing pitch; for insu- lating electric wires; for smokestack paint; for lubricants for heavy machinery; for preserving iron pipes from corrosion and acids; for coating poles, posts, and ties; for torredo-proof pile coating; for covering wood-block paving; as a substitute for rubber in the manu- facture of cotton garden hose; as a binder pitch for culm in making brickette and eggette coal. 3. OZOKERITE; MINERAL WAX; NATIVE PARAFFIN. This is a wax-like hydrocarbon, usually with a foliated structure, soft and easily indented with the thumb nail; of a yellow-brown or sometimes greenish color, translucent when pure, with a greasy feel- ing, and fusing at 56 to 63 F.; specific gravity, 0.955. ^ is essen- tially a natural paraffin. The name is derived from two Greek words, signifying to smell, and wax. Below is given the composition of (I) samples from Utah, and (II) from Boryslaw, in Galicia. Constituents. 1. II. Carbon 8S 47 8c 78 Hydrogen "O'H-/ 14 ^7 j*7 Total 100 04 The substance is completely soluble in boiling ether, carbon disulphides, or benzine, and partially so in alcohol. 374 THE NON-METALLIC MINERALS. The following, from a paper by Boverton Redwood, 1 will serve to show the character of the material from the various reported sources : Colorado. Dull black, hard, and pulverizable ; melting point, 76 C. Yields on distillation: Percentage , . - (by difference). Paraffin and oil 90.00 Loss in gas 2.12 Loss in water 2.60 Residue 5.28 Total 100.00 It commences to distill at 360 C., when nearly 3 per cent of oil setting at 30 C. comes over. At a much higher temperature it distills steadily and furnishes a product suitable for use as a source of paraffin. Baku. Specific gravity, 0.903; melting point, 76 C.: Paraffin mass 81.80 Gas 13.80 Coke 4.40 Total 100.00 Persia. Dark green, rather hard; specific gravity, 0.925 Light oil, 0.740 to 0.780 2.35 Light oil, 0.800 to 0.820 v. 3.50 Oil, 0.880 16.63 . Paraffin 53.55 Coke 16.73 Loss 7- 2 4 Total 100.00 1 Journal of the Society of Chemical Industry, XI, 1892, p. 114. HYDROCARBON COMPOUNDS. 375 Boryslaw. Specific gravity, 0.930. I, dark yellow; II, dark brownish black: Constituents. I. II. 4.32 *. so Kerosene o 780 to o 820 2C.6S 27.83 Lubricating oil, o 805 *3$ 7.64 6.0 1? Paraffin, etc. . ......... l izmo i oo * McKay and Larsen's Principles and Practice of Butter-making 8vo. i 50 Mandel's Handbook for Bio-chemical Laboratory i2mo, i 50 * Martin's Laboratory Guide to Qualitative Analysis with the Blowpipe . . I2mo, 60 Mason's Water-supply. (Considered Principally from a Sanitary Standpoint.) 3d Edition, Rewritten 8vo, 4 oo Examination of Water. (Chemical and Bacteriological.) i2mo, i 25 Matthew's The Textile Fibres 8vo, 3 50 Meyer's Determination of Radicles in Carbon Compounds. (Tingle.). .i2mo, Miller's Manual of Assaying i2mo, Minet's Production of Aluminum and its Industrial Use. (Waldo.) . . . . I2mo, Mixter's Elementary Text-book of Chemistry I2mo, Morgan's An Outline of the Theory of Solutions and its Results i2mo, 4 00 Morgan's Elements of Physical Chemistry izmo, 3 oo * Physical Chemistry for Electrical Engineers i2mo, i 50 Morse's Calculations used in Cane-sugar Factories i6mo, morocco, i 50 Mulliken's General Method for the Identification of Pure Organic Compounds. Vol. I. . Large 8vo, 5 oo O'Brine's Laboratory Guide in Chemical Analysis 8vo, 2 oo O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 oo Ostwald's Conversations on Chemistry. Part One. (Ramsey.) 12010, i 50 " " " " Part Two. (Turnbull.) i2mo, 2 oo * Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 8vo, paper, 50 Pictet's The Alkaloids and their Chemical Constitution. (Biddle.) 8vo, 5 oo Pinner's Introduction to Organic Chemistry. (Austen.) i2mo, i 50 Poole's Calorific Power of Fuels 8vo, 3 oo Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- ence to Sanitary Water Analysis i2mo, i 25 * Reisig's Guide to Piece-dyeing 8vo, 25 oo Richards and Woodman's Air, Water, and Food from a Sanitary Stand- point 8vo, 2 oo Ricketts and Russell's Skeleton Notes upon Inorganic Chemistry. (Part I. Non-metallic Elements.) 8vo, morocco, 75 Ricketts and Miller's Notes on Assaying : 8vo, 3 oo Rideal's Sewage and the Bacterial Purification of Sewage 8vo, 3 50 Disinfection and the Preservation of Food 8vo, 4 oo Riggs's Elementary Manual for the Chemical Laboratory 8vo, i 25. Robine and Lenglen's Cyanide Industry. (Le Clerc.) 8vo, 4 oo Rostoski's Serum Diagnosis. (Bolduan.) I2mo, i oo Ruddiman's Incompatibilities in Prescriptions 8vo, 2 oo * Whys in Pharmacy lamo, i oo Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo Salkowski's Physiological and Pathological Chemistry. (Orndorff.) 8vo, 2 50 Schimpf's Text-book of Volumetric Analysis i2mo, 2 50 Essentials of Volumetric Analysis i2mo, i ^5 * Qualitative Chemical Analysis 8vo, i 25 Spencer's Handbook for Chemists of Beet-sugar Houses i6mo, morocco, 3 oo Handbook for Cane Sugar Manufacturers i6mo, morocco, 3 oo Stockbridge's Rocks and Soils 8vo, 2 50 * Tillman's Elementary Lessons in Heat 8vo, i 50 * Descriptive General Chemistry 8vo, 3 oo Treadwell's Qualitative Analysis. (Hall.) 8vo, 3 oo Quantitative Analysis. (Hall.) 8vo, 4 oo Turneaure and Russell's Public Water-supplies 8vo, 5 oo Van Deventer's Physical Chemistry for Beginners. (Boltwood.) i2mo, i 50 * Walke's Lectures on Explosives 8vo, 4 oo Ware's Beet-sugar Manufacture and Refining Small 8vo, cloth, 4 oo Washington's Manual of the Chemical Analysis of Rocks 8vo, 2 oe Wassermann's Immune Sera : Haemolysins, Cytotoxins, and Precipitins. (Bol- duan.) i2mo, i oo Wells's Laboratory Guide in Qualitative Chemical Analysis, 8vo, i 50 Short Course in Inorganic Qualitative Chemical Analysis for Engineering Students i2mo, i 50 Text-book of Chemical Arithmetic i2mo, i 25 Whipple's Microscopy of Drinking-water. . 8vo, 3 50 Wilson's Cyanide Processes i2mo, i 50 Chlorination Process I2mo, i 50- Winton's Microscopy of Vegetable Foods 8vo, 7 5<> Wulling's Elementary Course in Inorganic, Pharmaceutical, and Medical Chemistry I2mo, 2 oo 5 CIVIL ENGINEERING. BRIDGES AND ROOFS HYDRAULICS. MATERIALS OF ENGINEERING. RAILWAY ENGINEERING. Baker's Engineers' Surveying Instruments zamo, 3 oo Bixby's Graphical Computing Table Paper igX24i inches. 25 ** Burr's Ancient and Modern Engineering and the Isthmian Cana *. (Postage, 27 cents additional.) 8vo, 3 50 Comstock's Field Astronomy for Engineers 8vo, 2 50 Davis's Elevation and Stadia Tables 8vo, i oo Elliott's Engineering for Land Drainage 12010, i 50 Practical Farm Drainage i2mo, i oo *Fiebeger's Treatise on Civil Engineering 8vo, 5 oe Flemer's Phototopegraphic Methods and Instruments 8vo, 5 oo Folwell's Sewerage. (Designing and Maintenance.) 8vo, 3 oo Freitag's Architectural Engineering. 2d Edition, Rewritten 8vo, 3 50 French and Ives's Stereotomy 8vo, 2 50 Goodhue's Municipal Improvements I2mo, i 75 Goodrich's Economic Disposal of Towns' Refuse 8vo, 3 50 Gore's Elements of Geodesy 8vo, 2 50 Hayford's Text-book of Geodetic Astronomy 8vo, 3 oo Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 Howe's Retaining Walls for Earth i2mo, i 25 Johnson's (J. B.) Theory and Practice of Surveying Small 8vo, 4 oo Johnson's (L. J.) Statics by Algebraic and Graphic Methods 8vo, 2 oo Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.). i2mo, 2 oo Mahan's Treatise on Civil Engineering. (1873.) (Wood.) 8vo, 5 oo * Descriptive Geometry 8vo, i 50 Merriman's Elements of Precise Surveying and Geodesy 8vo, 2 50 Merriman and Brooks's Handbook for Surveyors i6mo, morocco, 2 oo Nugent's Plane Surveying 8vo, 3 50 Omen's Sewer Design i2mo, 2 oo Patton's Treatise on Civil Engineering 8vo half leather, 7 50 Reed's Topographical Drawing and Sketching 4to, 5 oo Rideal's Sewage and the Bacterial Purification of Sewage 8vo, 3 50 Siebert and Biggin's Modern Stone-cutting and Masonry 8vo, i 50 Smith's Manual of Topographical Drawing. (McMillan. "> -8vo, 2 50 Sondericker's Graphic Statics, with Applications to Trusses, Beams, and Arches. 8vo, 2 oo Taylor and Thompson's Treatise on Concrete, Plain and Reinforced 8vo, 5 oo * Trautwire's Civil Engineer's Pocket-book i6mo, morocco, 5 oo Wait's Engineering and Archi ectural Jurisprudence 8vo, 6 oo Sheep, 6 50 Law of Operations Preliminary to Construction in Engineering and Archi- tecture 8vo, 5 oo Sheep, 5 50 Law of Contracts 8vo, 3 oo Warren's Stereotomy Problems in Stone-cutting 8vo, 2 50 Webb's Problems in the Use and Adjustment of Engineering Instruments. i6mo, morocco, i 25 Wilson's Topographic Surveying 8vo, 3 5 BRIDGES AND ROOFS. Boiler's Practical Treatise on the Construction of Iron Highway Bridges. .8vo, 2 oo * Thames River Bridge 4to, paper, 5 oo Burr's Course on the Stresses in Bridges and Roof Trusses, Arched Ribs, and Suspension Bridges 8vo, 3 5 6 Burr and Falk's Influence Lines for Bridge and Roof Computations. . . .8vo, 3 oo Design and Construction of Metallic Bridges 8vo, 5 oo Du Bois's Mechanics of Engineering. Vol. II Small 4to, 10 oo Foster's Treatise on Wooden Trestle Bridges 4to, 5 oo Fowler's Ordinary Foundations 8vo, 3 50 Greene's Roof Trusses 8vo, i 25 Bridge Trusses 8vo, 2 50 Arches in Wood, Iron, and Stone 8vo, 2 50 Howe's Treatise on Arches 8vo, 4 oo Design of Simple Roof-trusses in Wood and Steel 8vo, 2 oo Johnson, Bryan, and Turneaure's Theory and Practice in the Designing of Modern Framed Structures Small 4to, 10 oo Merriman and Jacoby's Text-book on Roofs and Bridges : Part I. Stresses in Simple Trusses 8vo, 2 50 Part II. Graphic Statics 8vo, 2 50 Part III. Bridge Design 8vo, 2 50 Part IV. Higher Structures 8vo, 2 50 Morison's Memphis Bridge 4to, 10 oo Waddell's De Pontibus, a Pocket-book for Bridge Engineers. . i6mo, morocco, 2 oo *Specifications for Steel Bridges lamo, 50 Wright's Designing of Draw-spans. Two parts in one volume 8vo, 3 50 HYDRAULICS. Bazin's Experiments upon the Contraction of the Liquid Vein Issuing from an Orifice. (Trautwine.) 8vo, 2 oo Bovey's Treatise on Hydraulics 8vo, 5 oo Church's Mechanics of Engineering 8vo, 6 oo Diagrams of Mean Velocity of Water in Open Channels paper, i 50 Hydraulic Motors 8vo, 2 oo Coffin's Graphical Solution of Hydraulic Problems i6mo, morocco, 2 50 Flather's Dynamometers, and the Measurement of Power 1210.9, 3- oo Folwell's Water-supply Engineering ' 8vo, 4 oo Frizell's Water-power 8vo, 5 oo Fuertes's Water and Public Health i2mo, i 50 Water-filtration Works i2mo, 2 50 Ganguillet and Kutter's General Formula for the Uniform Flow of Water in Rivers and Other Channels. (Bering and Trautwine.) 8vo, 4 oo Hazen's Filtration of Public Water-supply 8vo, 3 oo Hazlehurst's Towers and Tanks for Water-works 8vo, 2 50 Herschel's 115 Experiments on the Carrying Capacity of Large, Riveted, Metal Conduits 8vo, 2 oo Mason's Water-supply. (Considered Principally from a Sanitary Standpoint.) 8vo, 4 oo Merriman's Treatise on Hydraulics 8vo, 5 oo * Michie's Elements of Analytical Mechanics 8vo, 4 oo Schuyler's Reservoirs for Irrigation, Water-power, and Domestic Water- supply Large 8vo, 5 oo ** Thomas and Watt's Improvement of Rivers. (Post., 44C. additional. ).4to, 6 bo Turneaure and Russell's Public Water-supplies 8vo, 5 oo Wegmann's Design and Construction of Dams 4to, 5 oo Water-supply of the City of New York from 1658 to 1895 4to, 10 oo Williams and Hazen's Hydraulic Tables 8vo, i 50 Wilson's Irrigation Engineering Small 8vo, 4 oo Wolff's Windmill as a Prime Mover 8vo, 3 oo Wood's Turbines 8vo, 2 50 Elements of Analytical Mechanics 8vo, 3 oo 7 MATERIALS OF ENGINEERING. Baker's Treatise on Masonry Construction 8vo, 5 oo Roads and Pavements 8vo, 5 oo Black's United States Public Works Oblong 4to, 5 oo * Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 Burr's Elasticity and Resistance of the Materials of Engineering 8vo, 7 50 Byrne's Highway Construction 8vo, 5 oo Inspection of the Materials and Workmanship Employed in Construction. i6mo, 3 oo Church's Mechanics of Engineering 8vo, 6 oo Du Bois's Mechanics of Engineering. Vol. I Small 4to, 7 50 *Eckei's Cements, Limes, and Plasters 8vo, 6 oo Johnson's Materials of Construction Large 8vo, 6 oo Fowler's Ordinary Foundations 8vo, 3 50 * Greene's Structural Mechanics 8vo, 2 50 Keep's Cast Iron 8vo, 2 50 Lanza's Applied Mechanics 8vo, 7 50 Marten's Handbook on Testing Materials. (Henning.) 2 vols 8vo, 7 50 Maurer's Technical Mechanics 8vo, 4 oo Merrill's Stones for Building and Decoration 8vo, 5 oo Merriman's Mechanics of Materials 8vo, 5 oo Strength of Materials i2mo, i oo Metcalf's Steel. A Manual for Steel-users i2mo, 2 oo Patton's Practical Treatise on Foundations 8vo, 5 oo Richardson's Modern Asphalt Pavements 8vo, 3 oo Richey's Handbook for Superintendents of Construction i6mo, mor., 4 oo Rockwell's Roads and Pavements in France i2mo, i 25 Sabin's Industrial and Artistic Technology of Paints and Varnish. 8vo, 3 oo Smith's Materials of Machines i2mo, i oo Snow's Principal Species of Wood 8vo, 3 50 Spakling's Hydraulic Cement i2mo, 2 oo Text-book on Roads and Pavements i2ino, 2 oo Taylor and Thompson's Treatise on Concrete, Plain and Reinforced, 8vo, 5 oo Thurston's Materials of Engineering. 3 Parts 8vo, 8 oo Parti. Non-metallic Materials of Engineering and Metallurgy 8vo, 2 oe Part II. Iron and Steel 8vo, 3 50 Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their Constituents 8vo, 2 50 Thurston's Text-book of the Materials of Construction 8vo, 5 oo Tillson's Street Pavements and Paving Materials 8vo, 4 oo Waddell's De Pontibus. (A Pocket-book for Bridge Engineers.). . r6mo, mor., 2 oo Specifications for Steel Bridges i2mo, i 25 Wood's (De V.) Treatise on the Resistance of Materials, and an Appendix on the Preservation of Timber 8vo, 2 oo Wood's (De V.) Elements of Analytical Mechanics 8vo, 3 oo Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and Steel 8vo, 4 oo RAILWAY ENGINEERING. Andrew's Handbook for Street Railway Engineers 3x5 inches, morocco, I 25 Berg's Buildings and Structures of American Railroads 4to, 5 oo Brook's Handbook of Street Railroad Location i6mo, morocco, i 50 Butt's Civil Engineer's Field-book i6mo, morocco, 2 50 CrandalFs Transition Curve i6mo, morocco, i 50 Railway and Other Earthwork Tables 8vo, i 50 Dawson's "Engineering" and Electric Traction Pocket-book. i6mo, morocco, 5 oo 8 Dredge's History of the Pennsylvania Railroad: (1879). Paper, 5 oo * Drinker's Tunnelling, Explosive Compounds, and Rock Drills. 4to, half mor., 25 oo Fisher's Table of Cubic Yards Cardboard, 25 Godwin's Railroad Engineers' Field-book and Explorers' Guide. . . i6mo, mor., 2 50 Howard's Transition Curve Field-T>ook i6mo, morocco, i 50 Hudson's Tables for Calculating the Cubic Contents of Excavations and Em- bankments Svo, i oo Molitor and Beard's Manual for Resident Engineers i6mo, i oo Nagle's Field Manual for Railroad Engineers i6mo, morocco, 3 oo Philbrick's Field Manual for Engineers i6mo, morocco, 3 oo Searles's Field Engineering i6mo, morocco, 3 oo Railroad Spiral i6mo, merocco, i 50 Taylor's Prismoidal Formulae and Earthwork Svo, i 50 * Trautwine's Method of Calculating the Cube Contents of Excavations and Embankments by the Aid of Diagrams Svo, 2 oo The' Field Practice of Laying Out Circular Curves for Railroads. 1 2 mo, morocco, 2 50 Cross-section Sheet Paper, 25 Webb's Railroad Construction i6mo, morocco, 5 oo Wellington's Economic Theory of the Location of Railways Small Svo, 5 oo DRAWING. Barr's Kinematics of Machinery Svo, 2 50 * Bartlett's Mechanical Drawing Svo, 3 oo * " " Abridged Ed Svo, i 50 Coolidge's Manual of Drawing Svo, paper i oo Coolidge and Freeman's Elements of General Drafting for Mechanical Engi- neers Oblong 4to, 2 50 Durley's Kinematics of Machines Svo, 4 oo Emch's Introduction to Projective Geometry and its Applications . .Svo, 2 50 Hill's Text-book on Shades and Shadows, and Perspective Svo, 2 oo Jamison's Elements of Mechanical Drawing Svo, 2 50 Advanced Mechanical Drawing Svo, 2 oo Jones's Machine Design: Part I. Kinematics of Machinery Svo, i 50 Part II. Form, Strength, and Proportions of Parts Svo, 3 oo MacCord's Elements of Descriptive Geometry Svo, 3 oo Kinematics; or, Practical Mechanism Svo, 5 oo Mechanical Drawing ". 4to, 4 oo Velocity Diagrams Svo, i 50 MacLeod's Descriptive Geometry Small Svo, i 50 * Mahan's Descriptive Geometry and Stone-cutting Svo, i 50 Industrial Drawing. (Thompson.) Svo, 3 50 Moyer's Descriptive Geometry gvo, 2 oo Reed's Topographical Drawing and Sketching 4 to, 5 oo Reid's Course in Mechanical Drawing Svo, 2 oo Text-book of Mechanical Drawing and Elementary Machine Design. Svo, 3 oo Robinson's Principles of Mechanism 8vo, 3 oo Schwamb and Merrill's Elements of Mechanism 8vo, 3 co Smith's (R. S.) Manual of Topographical Drawing. (McMillan.) Svo, 2 50 Smith (A. W.) and Marx's Machine Design 8vo, 3 oo oo 25 50 Warren's Elements of Plane and Solid Free-hand Geometrical Drawing. i2mo, Drafting Instruments and Operations i2mo, Manual of Elementary Projection Drawing i2mo, Manual of Elementary Problems in the Linear Perspective of -Form and Shadow I2mo, Plane Problems in Elementary Geometry I2mo, 9 Warren's Primary Geometry I2mo, 75 Elements of Descriptive Geometry, Shadows, and Perspective 8vo, 3 50 General Problems of Shades and Shadows 8vo, 3 oo Elements of Machine Construction and Drawing 8vo, 7 So Problems, Theorems, and Examples in Descriptive Geometry 8vo, 2 50 Weisbach's Kinematics [and Power of Transmission. (Hermann and Klein.) 8vo, 5 o o Whelpley's Practical Instruction in the Art of Letter Engraving 12 mo, 2 oo Wilson's (H. M.) Topographic Surveying 8vo, 3 50 Wilson's (V. T.) Free-hand Perspective 8vo, 2 50 Wilson's (V. T.) Free-hand Lettering 8vo, i oo Woolf's Elementary Course in Descriptive Geometry Large 8vo, 3 oo ELECTRICITY AND PHYSICS. Anthony and Brackett's Text-book of Physics. (Magie.) Small 8vo, 3 oo Anthony's Lecture-notes on the Theory of Electrical Measurements. . . . i2mo, i oo Benjamin's History of Electricity 8vo, 3 oo Voltaic Cell 8vo, 3 oo Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.).8vo, 3 oo Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 oo Dawson's "Engineering" and Electric Traction Pocket-book. i6mo, morocco, 5 oo Dolezalek's Theory of the Lead Accumulator (Storage Battery). (Von Ende.) I2mo, 2 50 Duhem's Thermodynamics and Chemistry. (Burgess.) 8ve, 4 oo Flather's Dynamometers, and the Measurement of Power 12 mo, 3 oo Gilbert's De Magnete. (Mottelay.) 8vo, 2 50 Hanchett's Alternating Currents Explained i2mo, i oo Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 Holman's Precision of Measurements 8vo, 2 oo Telescopic Mirror-scale Method, Adjustments, and Tests. . . .Large 8vo, 75 Xinzbrunner's Testing of Continuous-current Machines 8vo, 2 oo Landauer's Spectrum Analysis. (Tingle.). 8vo, 3 oo Le Chateliers High-temperature Measurements. (Boudouard Burgess.) i2mo, 3 oo Lob's Electrochemistry of Organic Compounds. (Lorenz.) 8vo, 3 oo * Lyons'* Treatise on Electromagnetic Phenomena. Vols. I. and II. 8vo, each, 6 oo * Michie's Elements of Wave Motion Relating to Sound and Light 8vo, 4 oo Niaudet's Elementary Treatise on Electric Batteries. (Fishback.) i2mo, 2 50 * Rosenberg's Electrical Engineering. (Haldane Gee Kinzbrunner.). . .8vo, i 50 Ryan, Norris, and Hoxie's Electrical Machinery. Vol. 1 8vo, 2 50 Thurston's Stationary Steam-engines 8vo, 2 50 * Tillman's Elementary Lessons in Heat. . 8vo, i 50 Tory and Pitcher's Manual ef Laboratory Physics Small 8vo, 2 oo Ulke's Modern Electrolytic Copper Refining 8vo, 3 oo LAW. * Davis's Elements of Law 8vo, 2 50 * Treatise on the Military Law of United States 8vo, 7 oo * Sheep, 7 50 Manual for Courts-martial. i6mo, morocco, i 50 Wait's Engineering and Architectural Jurisprudence 8vo, 6 oo Sheep, 6 50 Law of Operations Preliminary to Construction in Engineering and Archi- tecture 8vo 5 oo Sheep, 5 5<> Law of Contracts 8vo, 3 oo Winthrop's Abridgment of Military Law I2mo> 2 So 10 MANUFACTURES. Bernadou's Smokeless Powder Nitro-cellulose and Theory of the Cellulose Molecule i2mo, 2 50 Bo Hand's Iron Founder I2mo, 2 50 "The Iron Founder," Supplement i2mo, 2 50 Encyclopedia f Founding and Dictionary of Foundry Terms Used in the Practice of Moulding i2mo, 3 oo * Eckel's Cements, Limes, and Plasters '..._. 8vo, 6 oo Eissler's Modern High Explosives 8vo, 4 oo Eft rent's Enzymes and their Applications. (Prescott.) 8vo, 3 oo Fitzgerald's Boston Machinist i2mo, i oo Ford's Boiler Making for Boiler Makers i8mo, i oo Hopkin's Oil-chemists' Handbook 8vo, 3 oo Keep's Cast Iron 8vo, 2 50 Leach's The Inspection and Analysis of Food with Special Reference to State Control Large 8vo, 7 50 * McKay and Larsen's Principles and Practice of. Butter-making 8vo, i 50 Matthews's The Textile Fibres 8vo, 3 50 Metcalf's Steel. A Manual for Steel-users I2mo, 2 oo Metcalfe's Cost of Manufactures And the Administration of Workshops. 8vo, 5 oo Meyer's Modern Locomotive Construction 4to, 10 oo Morse's Calculations used in Cane-sugar Factories i6mo, morocco, i 50 * Reisig's Guide to Piece-dyeing 8vo, 25 oo Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo Smith's Press-working of Metals 8vo, 3 oo Spalding's Hydraulic Cement I2mo, 2 oo Spencer's Handbook for Chemists of Beet-sugar Houses i6mo, morocco, 3 oo Handbook for Cane Sugar Manufacturers i6mo, morocco, 3 oo Taylor and Thompson's Treatise on Concrete, Plain and Reinforced 8vo, 5 oo Thurston's Manual of Steam-boilers, their Designs, Construction and Opera- tion 8vo, 5 oo * Walke's Lectures on Explosives " 8vo, 4 oo Ware's Beet-sugar Manufacture and Refining Small 8vo, 4 oo West's American Foundry Practice I2mo, 2 50 Moulder's Text-book i2mo 2 50 Wolff's Windmill as a Prime Mover 8vo, 3 oo Wood's Rustless Coatings : Corrosion and Electrolysis of Iron and Steel. .8vo, 4 oo MATHEMATICS. Baker's Elliptic Functions 8vo, i 50 * Bass's Elements of Differential Calculus i2mo, 4 oo Briggs's Elements of Plane Analytic Geometry I2mo, oo Compton's Manual of Logarithmic Computations I2mo, 50 Davis's Introduction to the Logic of Algebra 8vo, 50 * Dickson's College Algebra Large i2mo, 50 * Introduction to the Theory of Algebraic Equations Large i2mo, 25 Emch's Introduction to Projective Geometry and its Applications 8vo, 50 Halsted's Elements of Geometry 8vo, 75 Elementary Synthetic Geometry 8vo, 50 Rational Geometry i2mo, 75 * Johnson's (J. B.) Three-place Logarithmic Tables: Vest-pocket size. paper, 15 100 copies for 5 oo * Mounted on heavy cardboard, 8X 10 inches, 25 10 copies for 2 oo Johnson's (W. W.) Elementary Treatise on Differential Calculus . . Small 8vo, 3 oo Elementary Treatise on the Integral Calculus Small 8vo, I 50 11 Johnson's (W. W.) Curve Tracing in Cartesian Co-ordinates i2mo, i oo Johnson's (W. W.) Treatise on Ordinary and Partial Differential Equations. Small 8vo, 3 50 Johnson's (W. W.) Theory of Errors and the Method of Least Squares. i2mo, i 50 * Johnson's (W. W.) Theoretical Mechanics i2mo, 3 oo Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.) . i2mo, 2 oo * Ludlow and Bass. Elements of Trigonometry and Logarithmic and Other Tables 8vo, 3 oo Trigonometry and Tables published separately .Each, 2 oo * Ludlow's Logarithmic and Trigonometric Tables 8vo, i oo Mathematical Monographs. Edited by Mansfield Merriman and Robert S. Woodward .' Octavo, each i oo No. i. History of Modern Mathematics, by David Eugene Smith. No. 2. Synthetic Projective Geometry, by George Bruce Halsted. No. 3. Determinants, by Laenas Gifford Weld. No. 4. Hyper- bolic Functions, by James McMahon. No. 5. Harmonic Func- tions, by William E. Byerly. No. 6. Grassmann's Space Analysis, by Edward W. Hyde. No. 7. Probability and Theory of Errors, by Robert S. Woodward. No. 8. Vector Analysis and Quaternions, by Alexander Macfarlane. No. 9. Differential Equations, by William Woolsey Johnson. No. 10. The Solution of Equations, byj Mansfield Memman. No. u. Functions of a Complex Variable, by Thomas S. Fiske. Maurer's Technical Mechanics , 8vo, 4 oo Merriman's Method of Least Squares 8vo, 2 oo Rice and Johnson's Elementary Treatise on the Differential Calculus. . Sm. 8vo, 3 oo Differential and Integral Calculus. 2 vols. in one Small 8vo, 2 50 Wood's Elements of Co-ordinate Geometry 8vo, 2 oo Trigonometry: Analytical, Plane, and Spherical , 12 mo, i oo MECHANICAL ENGINEERING. MATERIALS OF ENGINEERING, STEAM-ENGINES AND BOILERS. Bacon's Forge Practice i2mo, i 50 Baldwin's Steam Heating for Buildings I2mo, 2 50 Barr's Kinematics of Machinery 8vo, 2 50 * Bartlett's Mechanical Drawing 8vo, 3 oo * " " " Abridged Ed 8vo, i 50 Benjamin's Wrinkles and Recipes 12100, 2 oo Carpenter's Experimental Engineering 8vo, 6 oo Heating and Ventilating Buildings 8vo, 4 oo Gary's Smoke Suppression in Plants using Bituminous Coal. (In Prepara- tion.) Clerk's Gas and Oil Engine Small 8vo, 4 oo Coolidge's Manual of Drawing '. 8vo, paper, i oo Coolidge and Freeman's Elements of General Drafting for Mechanical En- gineers Oblong 4to, 2 30 Cromwell's Treatise on Toothed Gearing xamo, i 50 Treatise on Belts and Pulleys i2mo, i 50 Durley's Kinematics of Machines 8vo, 4 oo Flather's Dynamometers and the Measurement of Power i2mo, 3 oo Rope Driving I2mo, 2 oo Gill's Gas and Fuel Analysis for Engineers i2mo, i 25 Hall's Car Lubrication i2mo, i oo Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 12 _ , _, _ . Button's The Gas Engine 8vo, 5 oo Jamison's Mechanical Drawing 8vo, 2 50 Jones's Machine Design: Part I. Kinematics of Machinery 8vo, i 50 Part II. Form, Strength, and Proportions of Parts 8vo, 3 oo Kent's Mechanical Engineers' Pocket-book i6mo, morocco, 5 oo Kerr's Power and Power Transmission 8vo, 2 oo Leonard's Machine Shop, Tools, and Methods 8vo, 4 oo * Lorenz's Modern Refrigerating Machinery. (Pope, Haven, and Dean.) . . 8vo, 4 oo MacCord's Kinematics; or, Practical Mechanism 8vo, 5 oo Mechanical Drawing 4to, 4 oo Velocity Diagrams 8vo, i 50 MacFarland's Standard Reduction Factors for Gases 8vo, i 50 Mahan's Industrial Drawing. (Thompson.) 8vo, 3 50 Poole's Calorific Power of Fuels 8vo, 3 oo Reid's Course in Mechanical Drawing 8vo, 2 oo Text-book of Mechanical Drawing and Elementary Machine Design. 8vo, 3 oo Richard's Compressed Air lamo, i 50 Robinson's Principles of Mechanism 8vo, 3 oo Schwamb and Merrill's Elements of Mechanism 8vo, 3 oo Smith's (0.) Press-working of Metals 8vo, 3 oo Smith (A. W.) and Marx's Machine Design 8vo, 3 oo Thurston's Treatise on Friction and Lost Work in Machinery and Mill Work 8vo, 3 oo Animal as a Machine and Prime Motor, and the Laws of Energetics. i2mo, i oo Warren's Elements of Machine Construction and Drawing 8vo, 7 50 Weisbach's Kinematics and the Power of Transmission. (Herrmann Klein. ) 8vo, 5 oo Machinery of Transmission and Governors. (Herrmann Klein.). .8vo, 5 oo Wolff's Windmill as a Prime Mover . .8vo, 3 oo Wood's Turbines 8vo, 2 50 MATERIALS OP ENGINEERING. * Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 Burr's Elasticity and Resistance of the Materials of Engineering. 6th Edition. Reset 8vo, 7 50 Church's Mechanics of Engineering 8vo, 6 oo * Greene's Structural Mechanics 8vo, 2 50 Johnson's Materials of Construction 8vo, 6 oo Keep's Cast Iron 8vo, 2 50 Lanza's Applied Mechanics 8vo, 7 50 Martens 's Handbook on Testing Materials. (Henning.) 8vo, 7 50 Maurer's Technical Mechanics 8vo, 4 oo Merriman's Mechanics of Materials 8vo, 5 oo Strength of Materials 121110, i oo Metcalf's Steel. A manual for Steel-users 121110, 2 oo Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo Smith's Materials of Machines i2mo, i oo Thurston's Materials of Engineering 3 vols., 8vo, 8 oo Part II. Iron and Steel 8vo, 3 50 Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their Constituents 8vo, 2 50 Text-book of the Materials of Construction. . 8vo, 5 oo Wood's (De V.) Treatise on the Resistance of Materials and an Appendix on the Preservation of Timber 8vo, 2 oo 13 Wood's (De V.) Elements of Analytical Mechanics 8vo, 3 oo Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and Steel 8vo, 4 oo STEAM-ENGINES AND BOILERS. Berry's Temperature-entropy Diagram I2mo, 25 Carnot's Reflections on the Motive Power of Heat. (Thurston.) i2mo, 50 Dawson's "Engineering" and Electric Traction Pocket-book. . . .i6mo, mor., oo Ford's Boiler Making for Boiler Makers i8mo, oo Goss's Locomotive Sparks 8vo, oo Hemenway's Indicator Practice and Steam-engine Economy i2mo, oo Button's Mechanical Engineering of Power Plants 8vo, 5 oo Heat and Heat-engines 8vo, 5 oo Kent's Steam boiler Economy 8vo, 4 oo Kneass's Practice and Theory of the Injector 8vo, i 50 MacCord's Slide-valves 8vo, 2 oo Meyer's Modern Locomotive Construction 4to, 10 oc Peabody's Manual of the Steam-engine Indicator izmo, i 50 Tables of the Properties of Saturated Steam and Other Vapors 8vo, i oo Thermodynamics of the Steam-engine and Other Heat-engines 8vo, 5 oo Valve-gears for Steam-engines 8vo, 2 50 Peabody and Miller's Steam-boilers 8vo, 4 oo Pray's Twenty Years with the Indicator '. Large 8vo, 2 50 Pupin's Thermodynamics of Reversible Cycles in Gases and Saturated Vapors. (Osterberg.) i2mo, i 25 Reagan's Locomotives: Simple Compound, and Electric i2mo, 2 50 Rontgen's Principles of Thermodynamics. (Du Bois.) 8vo, 5 oo Sinclair's Locomotive Engine Running and Management i2mo, 2 oo Smart's Handbook of Engineering Laboratory Practice i2mo, 2 50 Snow's Steam-boiler Practice .8vo, 3 oo Spangler's Valve-gears 8vo, 2 50 Notes on Thermodynamics I2mo, i oo Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo, 3 oo Thomas's Steam-turbines 8vo, 3 50 Thurston's Handy Tables 8vo, i 50 Manual of the Steam-engine 2 vols., 8vo, 10 oo Pant I. History, Structure, and Theory 8vo, 6 oo Part II. Design, Construction, and Operation 8vo, 6 oo Handbook of Engine and Boiler Trials, and the Use of the Indicator and the Prony Brake 8vo, 5 oo Stationary Steam-engines 8vo, 2 50 Steam-boiler Explosions in Theory and in Practice I2mo, i 50 Manual of Steam-boilers, their Designs, Construction, and Operation 8vo, 5 oo Weisbach's Heat, Steam, and Steam-engines. (Du Bois.) 8vo, 5 oo Whitham's Steam-engine Design 8vo, 5 oo Wood's Thermodynamics, Heat Motors, and Refrigerating Machines. . .8vo, 4 oo MECHANICS AND MACHINERY. Barr's Kinematics of Machinery 8vo, 2 50 *,Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 Chase's The Art of Pattern-making i2mo, 2 50 Church's Mechanics of Engineering 8vo, 6 oo Notes and Examples in Mechanics 8vo, 2 oo Compton's First Lessons in Metal-working I2mo, i 50 Compton and De Groodt's The Speed Lathe I2mo i 50 14 Cromwell's Treatise on Toothed Gearing i2mo, i 50 Treatise on Belts and Pulleys i2mo, t 50 Dana's Text-book of Elementary Mechanics for Colleges and Schoals. .i2mo, i 50 Dingey's Machinery Pattern Making i2mo, 2 oo Dredge's Record of the Transportation Exhibits Building of the World's Columbian Exposition of 1893 4to half morocco, 5 oo Du Bois's Elementary Principles of Mechanics: Vol. I. Kinematics 8vo, 3 50 Vol. II. Statics 8vo, 4 oo Mechanics of Engineering. Vol. I Small 4to, 7 50 Vol. II Small 4to, 10 oo Durley's Kinematics of Machines 8vo, 4 oo Fitzgerald's Boston Machinist i6mo, i oo Flather's Dynamometers, and the Measurement ef Power i2mo, 3 oo Rope Driving 1 21110, 2 oo Goss's Locomotive Sparks 8vo, 2 oo * Greene's Structural Mechanics 8vo, 2 50 Hall's Car Lubrication i2mo, i oo Holly's Art of Saw Filing i8mo, 75 James's Kinematics of a Point and the Rational Mechanics of a Particle. Small 8vo, 2 oo * Johnson's (W. W.) Theoretical Mechanics. . i2mo, 3 oo Johnson's (L. J.) Statics by Graphic and Algebraic Methods 8vo, 2 oo Jones's Machine Design: Part I. Kinematics of Machinery 8vo, i 50 Part II. Form, Strength, and Proportions of Parts 8vo, 3 oo Kerr's Power and Power Transmission 8vo, 2 oo Lanza's Applied Mechanics 8vo, 7 50 Leonard's Machine Shop, Tools, and Methods 8vo, 4 oo * Lorenz's Modern Refrigerating Machinery. (Pope, Haven, and Dean.). 8vo, 4 oo MacCord's Kinematics; or, Practical Mechanism 8vo, 5 oo Velocity Diagrams 8vo, i 50 Maurer's Technical Mechanics 8vo, 4 oo Merriman's Mechanics of Materials 8vo, 5 oo * Elements of Mechanics I2mo, i oo * Michie's Elements of Analytical Mechanics 8vo, 4 oo Reagan's Locomotives: Simple, Compound, and Electric I2mo, 2 50 Reid's Course in Mechanical Drawing 8vo, 2 oo Text-book of Mechanical Drawing and Elementary Machine Design. 8vo, 3 oo Richards's Compressed Air I2mo, i 50 Robinson's Principles of Mechanism 8vo, 3 oo Ryan, Norris, and Hoxie's Electrical Machinery. Vol. 1 8vo, 2 50 Schwamb and Merrill's Elements of Mechanism 8vo, 3 co Sinclair's Locomotive-engine Running and Management i2mo, 2 oo Smith's (O.) Press-working of Metals . .8vo, 3 oo Smith's (A. W.) Materials of Machines i2mo, i oo Smith (A. W.) and Marx's Machine Design < 8vo, 3 oo Spangler, Greenland Marshall's Elements of Steam-engineering 8vo, 3 oo Thurston's Treatise on Friction and Lost Work in Machinery and Mill Work 8vo, 3 oo Animal as a Machine and Prime Motor, and the Laws of Energetics. i2mo, i oo Warren's Elements of Machine Construction and Drawing 8vo, 7 50 Weisbach's Kinematics and Power of Transmission. ( Herrmann Klein. ) . 8vo , 5 oo Machinery of Transmission and Governors. (Herrmann Klein.). 8vo, 5 oo Wood's Elements of Analytical Mechanics 8vo, 3 oo Principles of Elementary Mechanics i2mo, i 25 Turbines. . 8vo, 2 50 The World's Columbian Exposition of 1893 4to, i oo 15 METALLURGY. Egleston's Metallurgy of Silver, Gold, and Mercury: Vol. I. Silver 8vo, 7 50 Vol. II. Gold and Mercury 8vo, 7 50 ** Iles's Lead-smelting. (Postage 9 cents additional.) i2mo, 2 50 Keep's Cast Iron 8vo, 2 50 Kunhardt's Practice of Ore Dressing in Europe 8vo, i 50 Le Chatelier's High-temperature Measurements. (Boudouard Burgess. )i2ino. 3 oo Metcalf's Steel. A Manual for Steel-users i2mo, 2 oo Minet's Production of Aluminum and its Industrial Use. (Waldo.) I2mo, 2 50 Robine and Lenglen's Cyanide Industry. (Le Clerc.) 8vo, 4 oo Smith's Materials of Machines I2mo, i oo Thurston's Materials of Engineering. In Three Parts 8vo, 8 oo Part II. Iron and Steel 8vo, 3 5<> Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their Constituents 8vo, 2 50 Ulke's Modern Electrolytic Copper Refining 8vo, 3 oo MINERALOGY. Barringer's Description of Minerals of Commercial Value. Oblong, morocco, 2 50 Boyd's Resources of Southwest Virginia 8vo, 3 oo Map of Southwest Virignia Pocket-book form. 2 oo Brush's Manual of Determinative Mineralogy. (Penfield.) 8vo, 4 oo Chester's Catalogue of Minerals 8vo, paper, i oo Cloth, i 25 Dictionary of the Names of Minerals 8vo, 3 50 Dana's System of Mineralogy Large 8vo, half leather, 12 50 First Appendix to Dana's New " System of Mineralogy." Large 8vo, i oo Text-book of Mineralogy 8vo, 4 oo Minerals and How to Study Them i2mo. i 50 Catalogue of American Localities of Minerals .Large 8vo, i oo Manual of Mineralogy and Petrography i2mo, 2 oo Douglas's Untechnical Addresses on Technical Subjects I2mo, i oo Eakle's Mineral Tables 8vo, i 25 Egleston's Catalogue of Minerals and Synonyms 8vo, 2 50 Hussak's The Determination of Rock-forming Minerals. (Smith.). Small 8vo, 2 oo Merrill's Non-metallic Minerals: Their Occurrence and Uses 8vo, 4 oo * Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 8vo, paper, 50 Rosenbusch's Microscopical Physiography of the Rock-making Minerals. (Iddings.) -8vo, 5 oo * Tollman's Text-book of Important Minerals and Rocks 8vo, 2 oo MINING. Beard's Ventilation of Mines I2mo, 2 50 Boyd's Resources of Southwest Virginia Cvo, 3 oo Map of Southwest Virginia Pocket-book form 2 oo Douglas's Untechnical Addresses on Technical Subjects 12010. i oo * Drinker's Tunneling, Explosive Compounds, and Roc'.c Drills. ,4to,hf. mor., 25 oo Eissler's Modern High Explosives 8vo 4 oo 16 Goodyear's Coal-mines of the Western Coast of the United States i2mo, 2 50 Ihlseng's Manual of Mining 8vo, 5 oo ** Iles's Lead-smelting. (Postage gc. additional.) i2mo, 2 50 Kunhardt's Practice of Ore Dressing in Europe 8vo, i 50 O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 oo Robine and Lenglen's Cyanide Industry. (Le Clerc.) 8vo, 4 oo * Walke's Lectures on Explosives 8vo, 4 oo Wilson's Cyanide Processes I2mo, i 50 Chlorination Process i2mo, i 50 Hydraulic and Placer Mining I2mo, 2 oo Treatise on Practical and Theoretical Mine Ventilation I2mo, i 25 SANITARY SCIENCE. Bashore's Sanitation f a Country House izmo, i oo Folwell's Sewerage. (Designing, Construction, and Maintenance.) 8vo, 3 oo Water-supply Engineering 8vo, 4 oo Fowler's Sewage Works Analyses i2mo, 2 oo Fuertes's Water and Public Health I2mo, i 50 Water-filtration Works i2mo, 2 50 Gerhard's Guide to Sanitary House-inspection i6mo, i oo Goodrich's Economic Disposal of Town's Refuse Demy 8vo, 3 50 Hazen's Filtration of Public Water-supplies 8vo, 3 oo Leach's The Inspection and Analysis of Food with Special Reference to State Control 8vo, 7 50 Mason's Water-supply. ( Considered principally from a Sanitary Standpoint) 8vo , 4 oo Examination of Water. (Chemical and Bacteriological.) 12 mo, i 25 Ogden's Sewer Design izmo, 2 oo Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- ence to Sanitary Water Analysis 12 mo, i 25 * Price's Handbook on Sanitation i2mo, i 50 Richards's Cost of Food. A Study in Dietaries I2mo, i oo Cost of Living as Modified by Sanitary Science i2mo, i oo Cost of Shelter I2mo, i oo Richards and Woodman's Air, Water, and Food from a Sanitary Stand- point 8vo, 2 oo * Richards and Williams's The Dietary Computer 8vo, i 50 RideaPs Sewage and Bacterial Purification of Sewage 8vo, 3 50 Turneaure and Russell's Public Water-supplies 8vo, 5 oo Von Behring's Suppression of Tuberculosis. (Bolduan.) i2mo, i oo Whipple's Microscopy of Drinking-water 8vo, 3 50 Winton's Microscopy of Vegetable Foods 8vo, 7 50 WoodhulPs Notes on Military Hygiene i6mo, i 50 * Personal H/giene i2mo, i oo MISCELLANEOUS. De Fursac's Manual of Psychiatry. (Rosanoff and Collins.). . . .Large i2mo, 2 50 Emmons's Geological Guide-book of the Rocky Mountain Excursion of the International Congress of Geologists Large Svo, i 50 Ferrel's Popular Treatise on the Winds Svo 4 oo Haines's American Railway Management i2mo, 2 50 Mott's Fallacy of the Present Theory of Sound i6mo, i oo Ricketts's History of Rensselaer Polytechnic Institute, 1824-1894. .Small Svo, 3 oc Rostoski's Serum Diagnosis. (Bolduan.) i2mo. i oo Rotherham's Emphasized New Testament Large Svo, 2 oo 17 Steel's Treatise on the Diseases of the Dog 8vo, 3 50 The World's Columbian Exposition of 1893 4to, i oo Von Behring's Suppression of Tuberculosis. (Bolduan.) i2mo, i oo Winslow's Elements of Applied Microscopy i2mo, i 50 Worcester and Atkinson. Small Hospitals, Establishment and Maintenance; Suggestions for Hospital Architecture : Plans for Small Hospital . 1 2 mo , i 25 HEBREW AND CHALDEE TEXT-BOOKS. Green's Elementary Hebrew Grammar i2mo, i 25 Hebrew Chrestomathy 8vo, 2 oo Gesenius's Hebrew and Chaldee Lexicon to the Old Testament Scriptures. (Tregelles.) Small 4to, half morocco, 5 oo Letteris's Hebrew Bible. Svo, 2 25 18 UNIVERSITY OF CALIFORNIA LIBRARY BERKELEY Return to desk from which borrowed. This book is DUE on the last date stamped below. . TECHHOLUUY LIBRARY MINERA WOV23 1953 LD 21-100m-ll,'49(B7146sl6)476 YC 33776'