The American Cyclopædia (1879)/Anthracite

ANTHRACITE (Gr., like coals, from , coal), the most condensed variety of

mineral coal, containing the largest proportion of carbon and the smallest quantity of volatile matter. Excepting the diamond, anthracite is the purest form of carbon in its natural state. The best specimens contain 95 per cent. carbon, but the average production of the purest beds of this coal will not exceed 90 per cent., and generally not more than 80 to 87 per cent. carbon. The volatile matter in the dense, hard varieties is almost exclusively water and earthy impurities, but in common varieties the volatile portion consists of water, hydrogen, oxygen, and nitrogen; while the ash or incombustible matter contains oxide of iron, iron pyrites, silica, alumina, magnesia, lime, &amp;c. The gradation of anthracite is arbitrary; there is no fixed limit in the descending scale at which anthracite becomes semi-anthracite. A coal containing 80 per cent. carbon may be and often is termed anthracite, while other coals containing 85 per cent. carbon are truly semi-bituminous. The superior density, irregular fracture, and general appearance of anthracite are distinguishing features to common observation; while water and ash take the place of hydrogen and oxygen, or bituminous matter. But anthracite which contains only 80 per cent. carbon, with 20 per cent. water and incombustible matter, is the lowest grade of commercial coal, and of little value as fuel.



MAP OF THE ANTHRACITE REGION OF PENNSYLVANIA, EXHIBITING ITS RELATIONS TO THE PRINCIPAL MARKETS.

BY S. HARRIES DADDOW, ENGINEER OF MINES, &amp;c.

&mdash;The constituents of anthracite, as determined by ordinary analyses, and generally published, are only approximate.

They are generally made from picked specimens, by many men and many methods, each giving widely diverse results even from the same coal, and the mere aggregates of carbon, volatile matter, and ash, while the distinguishing features and chemical constituents are seldom given. The change from anthracite to semi-anthracite is gradual and imperceptible in the coal beds of the prominent anthracite fields. There is no fixed point at which the one terminates or the other commences. The same uncertainty is manifest in all published analyses of mineral coal. No commonly adopted limit is assigned to the various gradations. Those called semi-anthracite in one place are termed anthracite in others, and vice versa. The same indefinite relations are observable between semi-anthracite and semi-bituminous, and between semi-bituminous and bituminous coals; while the gradations of all carbon compounds are alike indefinite and unsettled, down through cannel coal, bitumen, asphaltum, petroleum, naphtha, and carburetted hydrogen gases. The uncertainty, however, exists in the mean and not the extreme varieties. Hard, dense anthracite could not be mistaken for any other class; and while light, volatile semi-anthracite might be readily termed semi-bituminous, it could not be mistaken for anthracite. The following table gives the average aggregate constituents of the prominent varieties from the chief anthracite districts of the world:

ANALYSES OF ANTHRACITE.

The above table is compiled from the best available sources; and though the analyses are generally from hand specimens, and therefore not commercially useful, they are characteristic, and indicate the chief constituents of the prominent anthracites.—The anthracites of Pennsylvania are generally denominated white-ash or red-ash coals, but the color of the incombustible residue varies from pure white to gray, rose-pink, pink, light-red, brick-red, and brown; and this variation of color is as marked in the ash of bituminous

and all intermediate varieties of coal as in anthracite. The color of the ash is obtained from the oxide of iron, and is no criterion of the character or value of the coal, because these colors exist, from white to brown, in the lowest, oldest, and hardest anthracite, as well as in the upper, latest, softest, and most volatile semi-anthracite and bituminous coals.

&mdash;The nomenclature proposed by Prof. J. P. Lesley and adopted in “Coal, Iron, and Oil,” the latest standard work on anthracite, in which the beds are identified in the Pennsylvania anthracite

fields and connected with the bituminous coal beds of the Alleghany field, designates the lowest workable and consistent bed as A and the highest as N. But this nomenclature denotes series or groups of coal beds, rather than single beds. Fig. 1 presents the general type of the Pennsylvania anthracite strata. The figures in the column and in connection with the letters indicate thickness in feet. A number of small unworkable seams are not here represented. The 15 groups from A to N include 30 beds above 2 ft. thick and 20 seams less than 2 ft. This mode of grouping the beds in the anthracite fields was suggested by the natural divisions of massive sandstone and conglomerate strata in the coal measures, and the frequency with which some of the prominent groups united as a single bed or divided into two or three beds. In the southern anthracite field of Pennsylvania a few imperfect, irregular, and impure “nests” or pockets, rather than beds, of graphitic anthracite are occasionally found below A; but these local deposits have no general horizon, and are valueless for commercial purposes. Though pockets of good

coal are sometimes found from 5 to 20 ft. thick, they vary to as many inches, and do not exist as regular and consistent beds. A is usually a small bed of red-ash coal, but two or three thin seams are frequently found in this group which exist in the conglomerate, or close to it, everywhere. The coals of A generally contain from 10 to 20 per cent. of earthy matter, and are seldom workable. B is generally a large bed from 10 to 30 ft. thick, but frequently two beds of 5 to 10 ft. each. The lower part produces red-ash coal, and the upper gray or pink. The coal is excellent, and valued for blast furnances, though it contains more silica than the coal of any other workable bed higher in the measures. C is usually a group of small unworkable beds, producing white or gray-ash coals. D is a single bed of pure white-ash coal, generally from 6 to 10 ft. thick. E is the celebrated mammoth, which is a single bed from 20 to 70 it. thick in some localities, and a group of two and three in others. The coal is always of the white-ash variety, and is hard, dense, pure, and lustrous. Fully eight tenths of the present anthracite production is from this group. F is composed of two small beds of white-ash coal, and is not of much value; it is often known as the “rough vein.” G is generally a large bed from 7 to 10 ft. thick, and always a single one, though the lower stratum produces white-ash and the upper pink or gray-ash. It is locally known as the gray-ash or primrose vein, and is supposed to be identical with the Pittsburgh bed in the bituminous field. All the workable beds, from A to G inclusive, produce blast furnace coal; but the coals of the beds from G to N are less dense and contain less carbon and more volatile matter than the lower coals, and crumble under a high temperature. They are therefore not used for steam and furnace purposes generally, but are much valued for household uses, excepting large furnace heaters. They evolve an intense heat, and are free-burning, but will often “clinker” under a strong draught. In the preceding analytical table the highest percentage of carbon is 94.10 (No. 6), which is a hand specimen from the mammoth bed, E, in the Pottsville district; but it is a well known fact that the mammoth coals of the Lehigh district are equally as pure and generally more dense than any other anthracite. The average, therefore, of Nos. 1, 2, 3, 4, and 6 will give the mean of the hardest and purest anthracite; while No. 5 (M) is a type of the upper coals, and approaches the limit of the true anthracite, as shown by 7 and 8, which are semi-anthracite and semi-bituminous. The density and hardness of the coal decrease from A to N in the ascending order, while the volatile matter increases from N to A in the descending order; and the proportions of carbon increase and decrease in the same ratio and order. The coals of the lower beds are most hard and dense. The middle beds produce the purest coal, and the coal of the upper beds is most soft and friable under heat. The

same description would apply to the general decrease of carbon and increase of volatile matter in these coal beds from east to west. There is a gradual decrease also in the dimensions of the beds in the same direction. The same gradual change from hard anthracite to semi-anthracite and bituminous is as marked a feature in the South Wales (English) coal fields as in the Pennsylvania coal fields. The general features and fractures of hard anthracite are peculiar and noticeable to the common observer. They are massive, hard, dense, amorphous or conchoidal in fracture, with fine, sharp edges when broken, and a rich satin or an iron-black sub-metallic lustre. With some local exceptions, the softer varieties, both red and white-ash, are less massive, hard, and dense, more regular and cubical in fracture, and, exclusive of the upper red-ash beds, less rich and lustrous.—The prominent anthracite fields of the world are those of Pennsylvania and South Wales, which produce nine tenths of the quantity used. The developed coal fields of the world embrace an area of about 350,000 sq. m., of which over 300,000 are in the United States, exclusive of lignite. (See .) About 2,000 sq. m. of this entire area contain anthracite, of which half is in the United States, including the somewhat doubtful New England coal fields. The entire coal production of the world in 1871 was between 225 and 250 million tons, of which England produced 110 millions and the United States 41 millions. About 20 millions of the entire amount was anthracite, of which 15 million tons were produced in Pennsylvania, and the remainder in South Wales, France, and other countries.—The South Wales coal field lies on the northwest of the Bristol channel, extending from St. Bride's bay in the east to Pontypool

in the west, a distance of 90 m., with a maximum breadth of 60 m. Its mean breadth is less than 20 m., presenting an area of about 1,500 sq. m., of which only 1,000 contain workable coal beds. It is divided by an axis parallel to its strike, and divided also into numerous intermediate basins, while the measures undulate both from E. to W. and from N. to S. The deepest part of the field is supposed to be 8,000 ft. Most of the mining has been done by “drifts,” and but few shafts had been sunk to any great depth up to 1864. Twenty-three workable seams exist in the principal basins, averaging altogether 92. ft. of coal. Of these, 12 are from 3 to 9 ft. thick, and 11 from 18 in. to 3 ft. Besides these there are numerous smaller seams from 6 to 18 in. thick. On the N. side of the field the coal is anthracite in character, and resembles the anthracites of Pennsylvania, though generally containing more hydrogen or volatile matter; on the E. or N. E. the coal is semi-bituminous, and is used extensively, both raw and coked, in the blast furnaces of the region. On the S. side the coal is of a bituminous character. The change from anthracite to semi-bituminous and bituminous is gradual, and much the same in its metamorphic phases as we find existing in the coal fields of Pennsylvania. There are 16 thin seams of ironstone interstratified with the coal; the general yield of this ore is not over 30 per cent. of metal in the furnace. The coal production of South Wales in 1854 was 8,550,270 tons; of this amount only 1,000,000 tons was anthracite, the total being the products of 245 collieries.



2&mdash;Group of Pennsylvania Anthracite Basins.

&mdash;The anthracites of Pennsylvania exist in four parallel coal fields, in the counties of Schuylkill, Carbon, Columbia, Northumberland, and Luzerne, embracing an area of 470 sq. m. Within these fields numerous parallel basins or synclinal troughs are formed by the peculiar undulations of the strata, which dip at every angle from horizontal to perpendicular. Fig. 2 represents the general grouping of the principal basins of the southern Pennsylvania anthracite field, and the eastern part of the middle field, without reference to local peculiarities and abrupt dips.

PENNSYLVANIA ANTHRACITE FIELDS.

Coal was discovered in the Wyoming valley soon after its settlement, but the first authentic

account which we find of the use of anthracite in the United States was in 1768-'9, when it was used by two blacksmiths from Connecticut named Gore. One of these brothers, Jude Obadiah Gore, related the facts to Judge Jesse Fell of Wilkesbarre, who subsequently communicated them to Silliman's “Journal” and Hazard's “Register.” In 1776 coal was quarried from the Baltimore bed near Wilkesbarre and the Smith mine near Plymouth, and taken down the Susquehanna in arks to the government arsenal at Carlisle. This trade was continued during the revolutionary war, and anthracite was used by the blacksmiths and gunsmiths of the lower Susquehanna from that time forth; but from the difficulty of making it burn it was not used for domestic purposes till 1808, when Judge Fell succeeded in burning “stone coal” in a grate of his own construction. Anthracite was sold in the vicinity of Wilkesbarre to the smiths at $3 a ton, and in Marietta, on the lower Susquehanna, at $8 to $9 a ton from 1810 to 1814. This was probably the first successful use of anthracite for general purposes in the world. The earliest record of the production of anthracite in France, as given by Taylor, is in 1814; while Mr. Blakewell, an English geologist, says the Welsh coals were “inferior” and not used for domestic purposes in 1813, and but “little used” in 1828.—The northern or Wyoming coal field is naturally divided into two regions, the Lackawanna and the Wyoming, and these into several districts. The Lackawanna region includes the districts on the Lackawanna creek, which empties into the Susquehanna at Pittston. The districts are the old or original Lackawanna, at and around Carbondale, the Scranton, and the Pittston. Around these centres the early developments of the Lackawanna region were made, and collieries clustered. The Carbondale district was opened in 1829 by the Delaware and Hudson company's canal and railroad; the Scranton district by the Delaware, Lackawanna, and Western railroad, in 1854; and the Pittston district by the Susquehanna canal in 1843, and the Pennsylvania coal company's railroad in 1850. The production of the Wyoming or northern coal field in 1871 was 6,481,171 tons. Of this amount 2,867,598 tons was sent from the Wyoming region, and 3,613,573 from the Lackawanna. There are now (1873) nine railroads and two canals employed in transporting coal from these regions. The coal beds in the Wyoming portion extend to K (fig. 1), but in the Lackawanna the number is less, extending only to H or I. The coal of the entire field is anthracite.—The first or southern and middle anthracite fields are the next in size and importance, and in order of development. Their topography and geology differ materially from the northern field, as shown by fig. 2 from Lesley. The valleys in which the coal exists are comparatively narrow, while both anticlinals and synclinals and the strata of the measures are more abrupt than those of the former.

This field terminates in the east on the Lehigh river, in a single point or synclinal trough. In the west are two terminal points or prongs, which are wide apart at their extremities near the Susquehanna. Its extreme length is 73 m. to the end of the Dauphin or south fork, and 10 m. less by the Lykens Valley or north fork. Its mean breadth is 2 m., and its maximum, at Pottsville, 5 m. The number of coal beds is greater in this than in any of the other anthracite fields. The coal of the E. end is hard anthracite; of the Lykens Valley fork, semi-anthracite; and of Dauphin fork, semi-bituminous. The middle anthracite field is divided longitudinally by the Locust mountain anticlinal, over which the coal beds connect at several points. It is divided into two regions. The Mahanoy region is 25 m. long, with a mean breadth of nearly 2 m. Its basins are narrow and deep, and the strata abrupt. The Shamokin or northern part, not shown in fig. 2, is 20 m. long, with a mean breadth of 2½ m. The basins are wider, of less depth, and the strata of less inclination, than the former. The highest bed in this field is K. The coal is generally anthracite, except at the W. extremity, where it is semi-anthracite. The earliest records we find of the existence of coal in the southern and middle coal fields are those on Scul's map of Pennsylvania and Faden's “Atlas of North America” (1810-'17). The first discovery for practical purposes, however, was made in 1791 by a hunter named Philip Ginter on the Lehigh end of the southern coal field, and on the site of the since famous Lehigh coal quarry at Summit Hill. In the following year the “Lehigh Coal Mine Company” was formed by Robert Morris, J. Anthony Morris, Cist, Weist, Hillegas, and others, who secured 6,000 acres of land and opened the quarry the same year (1792) to test the character and value of the coal. In 1798 a charter was obtained by this company for a sluice navigation on the Lehigh, and in 1803 six arks with 600 tons of coal, from the Summit Hill quarry, were started down the river; but only two, with less than 100 tons each, reached Philadelphia. The city authorities purchased the coal to supply a steam engine used at the water works, then in Broad street; but it could not be made to burn, probably because it was tried in large lumps, and was broken up to gravel the walks of the grounds. In 1806 another ark load was taken to Philadelphia with no better success. It appears, however, from a brief account of “The Discovery of Anthracite on the Lehigh,” in the memoirs of the historical society of Pennsylvania, written by Dr. T. C. James of Philadelphia, who had visited the mines, that he had commenced using stone coal in the winter of 1804, and, having laid in a supply from this and the former cargoes, continued to use it to the day of publication in 1826. About this time (1800) William Morris, whose mines were near Port Carbon, Schuylkill county, took a load of coal to Philadelphia, but did not succeed in selling

or bringing his new “stone fuel” into notice. In 1814 two arks of coal reached Philadelphia, of five which were started from the mines, and these two cargoes were sold to Messrs. White and Hazard at the Schuylkill Falls wire manufactory, at $21 per ton. But previously, in 1812, Col. George Shoemaker of Pottsville had taken nine wagon loads of coal from his mines at Centreville, near Pottsville, to Philadelphia, and had disposed of two loads at the cost of transportation to these gentlemen, who desired to succeed in using it at their manufactory. Mr. White and his firemen spent half a day in the attempt to burn it without success. At noon they closed the furnace doors and went to their dinner in disgust with “stone coal;” but on their return they were astonished to find the doors red-hot and the furnace in danger of melting. Since then anthracite has been a desirable and eminently available fuel for all purposes. Col. Shoemaker, however, had disposed of the other seven loads to others who did not succeed in making the coal burn, though this was the free-burning red-ash variety, and they obtained a writ from the city authorities for his arrest as an impostor and swindler, who had sold them rocks for coal. The Lehigh navigation was improved in 1820, and during that year 365 tons of anthracite—which heads the column of the trade—was sent to Philadelphia and sold at $8&mdash;50 a ton. From this time the anthracite trade has steadily increased. Previous to 1847 most of the Lehigh coal was obtained from the open quarry in the mammoth or E bed (not an accumulation of beds, as is generally supposed), on the spot where the coal was first discovered. In 1847 about 2,000,000 tons had been sent from this quarry, and 30 to 40 acres had been excavated from the bed, which is here 50 ft. thick. Since this date the quarry method has been abandoned for regular mining operations by tunnels and slopes. The original “Coal Mine Company” leased in 1817 their whole property and privileges to Messrs. White, Hazard, and company, for 20 years, at an annual rental of one ear of corn! but they were bound to deliver for their own benefit 40,000 bushels of coal annually in Philadelphia. These gentlemen formed their interests into a stock company—the “Lehigh Coal Company”—and also organized the Lehigh navigation company, afterward incorporated as the Lehigh navigation and coal company, and subsequently changed to the Lehigh coal and navigation company. The stock of the old coal mine company was bought up by the new organization. At first the shares, representing 50th parts of the whole property, were bought at $150 each; the last brought $2,000. The number of tons shipped by the Lehigh canal in 1871 was 740,630, and the total amount by canal from the commencement of the trade is 26,139,540 tons, of which, however, a considerable portion was mined in other regions. The Schuylkill canal was projected in 1814, and so far completed in 1822 that 1,480 tons were shipped over it to Philadelphia.

Since then 28,700,015 tons have passed through it, of which 1,010,171 tons were shipped in 1871. The first railway built in the United States, except one of three miles at Quincy, Mass., was a gravity road from the Lehigh quarry at Summit Hill to the canal at Mauch Chunk, a distance of 9½ m. This was used from 1827 to 1872 for the transportation of anthracite; but on the completion of the Nesquehoning tunnel through the Locust mountain the old gravity line was abandoned as a coal road, and is now devoted to pleasure excursions, for which it has long been famous on account of the novelty of the ride and the picturesque grandeur—sometimes beauty—of the rapidly changing scenes. The view from the top of Mt. Pisgah, which towers over the waters of the Lehigh, is remarkably wild and grand. The numerous railroads built as feeders to the Lehigh and Schuylkill canals and the principal trunk lines will be found in an accompanying table. The Philadelphia and Reading railroad, opened from Pottsville to Philadelphia in 1841, had transported 62,128,735 tons of anthracite up to 1872, of which 4,584,450 tons were shipped during 1871. The Lehigh Valley railroad was opened from Mauch Chunk to Easton in 1853, and transported 2,889,074 tons in 1871, and a total of 22,981,252 since its completion. This line has since been extended through the Wyoming valley and into the state of New York, on the line of the Susquehanna river. The Lehigh and Susquehanna railroad, opened from the head of navigation on the Lehigh into the Wyoming region in 1846, was extended to Easton as a great trunk line in 1867, and during the next year 1,058,054 tons were transported over it. The term “Lehigh coal region” originally designated only that portion of the southern anthracite field which extended from Tamaqua on the Little Schuylkill to the Lehigh river; but since the completion of the Beaver Meadow and Hazleton feeders to the main line of canal the name has been applied to all the small middle basins, of which there are six, though three of these—the Little, Big, and Lower Black Creek basins—are on a tributary of the Susquehanna, and cannot properly be termed Lehigh basins. They produce a hard, dense, amorphous coal, resembling the original Lehigh coal in both feature and character. The geology of these small basins is similar to that of the E. end of the southern and middle anthracite fields. They are long, narrow, canoe-like troughs, nearly parallel in strike with themselves, and with the larger fields to the south, north, and east. The upper productive coal bed in these small basins is E. No. 3 in the preceding analytical table represents the general type of these basins. The small percentage of ash, however, is an exception.—The number of collieries in these anthracite regions in 1871 was 437, and their entire production, including home consumption (not in the tables), was 17,000,000 tons; and 52,227 men and boys were employed in and about the mines.

TABLE OF ANTHRACITE PRODUCTION IN PENNSYLVANIA. (From Bannan and Ramsey's &ldquo;Coal Trade Statistical Begister.&rdquo;)

CANALS BUILT EXCLUSIVELY OR CHIEFLY FOR THE TRANSPORTATION OF ANTHRACITE.

CAPITAL INVESTED IN MINING AND TRANSPORTING ANTHRACITE.

RAILROADS BUILT EXCLUSIVELY OR MAINLY FOR THE TRANSPORTATION OF ANTHRACITE.

&mdash;The New England anthracite field, embracing the Portsmouth basin in Rhode Island and its continuation, the Mansfield basin in Massachusetts, is greater in area than all the Pennsylvania anthracite fields, but its value for commercial purposes bears no comparison. The

general formation of the beds resembles that of the lower irregular beds or pockets in the southern Pennsylvania field below A; and the impure, graphitic character of the coal is the same. In both the coal exists in “nests” rather than beds, sometimes 10 and even 20 ft. thick, but often not as many inches, and frequently they disappear entirely. In the Pennsylvania anthracite fields the palæozoic sedimentary strata, between the coal measures and the igneous rocks, are between 5 and 7 m. in thickness; while the sedimentary strata below the New England field are comparatively thin, and so highly crystallized or metamorphosed by heat as to have been mistaken by the early geologists for the gneissic rocks. Dr. Edward Hitchcock, however, maintains that the whole region, embracing not less than 500 sq. m., is a true coal field, which has experienced more than ordinary metamorphic action both mechanical and chemical. He says: “The mechanical forces seem to have operated on the strata containing the coal in a lateral direction, so as not only to raise them into highly inclined positions, but also to produce plaits or folds. . . . The chemical metamorphoses which these rocks have experienced consist mainly in such effects as heat would produce.” Prof. Silliman, Prof. Jackson, and Dr. Hitchcock have given favorable opinions in regard to the probable future productiveness of this field and the commercial value of the coal. The developed coal beds are three in number. Their dimensions are variable, but may be averaged from 3 to 7 ft. respectively, when in their best condition. At Portsmouth the principal bed has been mined by a slope of 600 ft. in length, inclining at 30° to 35°, to a vertical depth of 300 ft.; from the

bottom of which gangways were driven 1,000 ft. in length on the strike of the bed, which increased and decreased from 16 inches to as many feet. Mining operations have been attempted in many localities in this field, but all have ended in failure, owing to the disappearance or faulty character of the coal beds. The amount of coal mined from the field has been insignificant, and no trustworthy statistics have been recorded. The product, however, when pure and solid, compares favorably with the Pennsylvania anthracite, though usually the best of it contains more water, graphite, and earthy impurities. It is probable that deep and well conducted mining operations will eventually develop this field in a remunerative manner. The diamond drill can now be used before incurring the cost of pits and mining operations, and it may reasonably be anticipated that purer coal and more regular beds will be found at greater depth.—The Virginia anthracite field, which may be appropriately termed the New river coal field, in Montgomery and Pulaski counties, in S. W. Virginia, consists of two narrow, parallel basins on Price's and Brush mountains. Price's mountain is a narrow, short synclinal ridge, which rises in the Silurian limestones of the great valley range, and is part of the watershed between the James and New rivers. In this ridge the coal is enclosed as a narrow trough or basin, with an eastern dip of 30°, while the true western dip is inverted and dips E. at an angle of 80° or 85°. Thus the bottom slate of the lower bed is the roof of the upper bed, and the basin may be generally represented by an Italic capital V; but the force which tilted and folded the strata in this inverted manner distorted the coal measures and crushed and ruined a large part of the coal, while slips and other forms of fault render the operations of mining

in this basin uncertain and precarious. The coal of Price's mountain basin is a true anthracite, but less dense, lustrous, and pure than that of Pennsylvania. The Brush mountain basin lies at the E. base of the North mountain, and resembles the opposite Price's mountain basin in lithological structure; but the inverted strata of the W. side have been destroyed, except in a few localities, by erosion. In some few places where the inverted strata exist in this basin, they are folded back, so that the coal beds, which in their normal condition must have dipped to the west, are now lying on their opposite dip, and the strata of the entire basin in such localities dip east, abutting abruptly against the underlying sandstones or limestones. The coal of this basin is semi-anthracite. Coal has been mined in a small way from numerous localities in these basins, but to the present time (1873) it has all been drawn in wagons from the mines to the Virginia and Tennessee railroad, a distance of from 2 to 8 m. The total amount mined cannot exceed 15,000 to 20,000 tons up to the year 1873. It has been used successfully in grates, stoves, cupola furnaces, puddling furnaces, and locomotives, but has not been tested in the blast furnace. Near the surface the coal is weak and friable, but at considerable depth it becomes more dense, solid, and pure. Much aluminous and carbonaceous shale exists in connection with this coal, and sometimes excludes it entirely, forming a “fault.” The entire area of these two basins cannot exceed 10 sq. m. They are merely narrow synclinal belts, with an occasional repetition or fold forming two parallel basins, seldom more than 500 yards wide inclusively. The coal-bearing strata of this range or belt, however, are much more extensive than those embraced in the New river coal field, and extend over 200 m. N. E. and nearly 100 m. S. W. It is found in Sidelong hill, a continuation of Blue or North mountains in Pennsylvania, and exists in a basin of considerable extent on North mountain, a short distance W. of Martinsburg, West Va. In this locality there are two basins, one on the E. side of the mountain and another on the W. side, or rather on the summit of the mountain. That on the east is narrow and folded in the form of a V, the left or E. side inverted in the usual form of this range; but that on the summit is more regularly stratified, forming a comparatively shallow basin. Here we find all the indications of a true basin of the carboniferous era. The conglomerate and the red shale (Nos. XII. and XI. of the Pennsylvania geological survey) are in regular order and position, and the lower beds of coal are identical with A, B, and C of the Pennsylvania fields, in the order of stratification, character of bed, and color of ash. The area of this small upper basin is perhaps 5 sq. m. It lies on the head waters of Back creek, which flows into the Potomac W. of Martinsburg. Yet notwithstanding the greater regularity and order of these anthracite beds, they are faulty and

too small and impure to be mined for ordinary commercial purposes. The beds range from 3 to 5 ft. in thickness, of which two thirds may produce marketable coal. This range of coal-bearing strata may be traced with occasional gaps from this place to New river. The coal beds have been developed in a small way at the Dora mines on the North fork of the Shenandoah, W. of Staunton, where anthracite of good character has been mined for local use. The next point at which the coal has been mined is W. of Fincastle on Catawba creek. From here it has been dug into in many places to the Brush mountain basin on New river, and from New river it has been opened at many points to the Tennessee line; but the only localities yet developed, where this range contains beds in workable condition and productive of good coal for ordinary purposes, are those particularly described, including the Dora mines, which however are the most doubtful. This range of coal deposits has always been considered by geologists as belonging to the proto-carboniferous or false coal measures, Recent investigations have cast doubt on this classification, and those most familiar with the geology of the region are inclined to place it in the true coal measures as identical with the strata of the Pennsylvania coal fields.—Besides the principal anthracite fields already described, there are other small, partially developed, and less known deposits of anthracite in Arkansas, New Mexico, Sonora, and Oregon.—Of the remaining anthracite deposits of the world, those of France are most largely developed. The first and most extensive is a continuation of the Belgian coal field, in the department of Le Nord. The coal is of a dry or semi-anthracite character in a portion of the French extension, and about one half the coal products of this field is denominated anthracite in the French reports, but it is not strictly anthracite. The other French fields producing anthracite are named from the departments of Pas-de-Calais, Calvados, Sarthe, Maine-et-Loire, Loire-Inférieure, Corrèze, Puy-de-Dôme, Haute-Saône, Tarn, Haute-Loire, Ardèche, Isère, and Hautes-Alpes. The total annual production of coal in France is now (1873) over 10,000,000 tons, of which about 2,000,000 tons is anthracite and semi-anthracite, and of the latter more than one half is the product of the field of Le Nord. The European anthracite field next in importance to these is that of Donetz in S. Russia, between the Dnieper and Donetz rivers, which is perhaps the largest connected field containing anthracite yet developed. It embraces over 8,000 sq. m. of coal area, but, like the South Wales and Pennsylvania anthracite fields, one end contains anthracite and the other bituminous coal beds, according to Murchison; while anthracite and bituminous beds are found in the same locality, and the undulations of the strata, which dip from 20° to 70°, indicate a close resemblance to the peculiarities of the Pennsylvania anthracite fields. An analysis of

this anthracite gave 94.234 per cent. carbon. Anthracite also exists in Spain, Portugal, Germany, Austria, Norway, Persia, India, China, and South America; and generally anthracite is found in connection with the altered or metamorphic rocks, which accompany all great coal formations to a greater or less extent.—Anthracite undoubtedly owes its existence to a superior heat or a comparatively high temperature during its formation. The hardest and most dense anthracite is always found where the coal has been subject to a high temperature; but where the heat has been most intense, graphite rather than coal is found. In the New England field the outcrops of the coal beds frequently yield plumbago, which is collected and sold as “British lustre,” and nests of pure graphite are found in the beds at considerable depth. An analogous condition is found in the pockets of carbonaceous coal which exist below A in the southern Pennsylvania field. The proportions of carbon are due to the varying degrees of heat to which the coal or the elements forming anthracite have been subjected. This fact is fully illustrated in the Pennsylvania anthracite beds, where the lowest contain the most carbon and the highest (in the measures) the most volatile matter. Where the coal is nearest to the igneous or plutonic rocks, whether granitic or metamorphic, whether in the deepest parts of the coal basins or on their edges, the conditions are the same, and all true coal fields are alike in these conditions. It is true, the Richmond (Va.) bituminous coal field is formed in the crater of an extinct volcano; but that field is a late creation of the Jurassic period, and was deposited when the earth and the rocks beneath it were comparatively cool, and even there a trap dike is intruded—evidently long after the completion of the coal field—between the beds. The effect of this heated and volcanic mass of rock has been to coke a coal bed 60 ft. beneath it, and burn one 10 ft. above it to a graphitic cinder. The general effect of trap intrusions seems to be the same in all cases, but the altered bituminous coal under such circumstances is rather a coke than an anthracite, which differs greatly in appearance, though the constituents are the same. Prof. H. D. Rogers explains the formation of anthracite by supposing it to be the result of altered bituminous coal metamorphosed by intense heat, and of course by heat induced subsequent to the formation of the bituminous beds; and he further explains the escape of the volatile portion of the latter as gas through cracks and openings caused by the plication of the anthracite strata. This plication follows closely the general type of the eastern palæozoic rocks, which are intensely crushed and folded near the contact of their edges with the igneous or granitic rocks, and much less plicated and distorted in a western direction. This fact undoubtedly led to the above theory, which seems as natural as it is ingenious: but the facts do not sustain the theory. 1st. The upper beds

and strata are more dislocated, distorted, and crushed than the lower beds, as plainly demonstrated by the plication of the strata on the apex of the leading anticlinals in the southern field. 2d. The measures are more plicated and crushed at the western extremity of this field, in the Dauphin or south prong, than at the eastern extremity; yet the coal of the latter is a dense, hard anthracite, while that of the former is semi-bituminous. 3d. The heat must have been most intense during the early stages of coal formation. In view of these facts, it has recently been contended that true anthracite is not a metamorphosis of bituminous coal, but as much a normal creation as the bituminous variety itself from a combination of its constituents under superior heat, however the original elements were produced. (See .)—The faults and irregularities of the anthracite beds and strata are the result of crust movements, and the plication of the distorted and crushed rocks indicates contraction, both lateral and perpendicular, as the cause. The effects of a combined lateral and perpendicular movement are simply those which are evident in the plication of the anthracite beds of the southern Pennsylvania fields, and their accompanying shales; but the crust movements have been slow and uniform, bending rather than breaking the strata, except in cases of sharp foliation of anticlinals or synclinals. Where the folding has been most abrupt the strata are inverted, and the coal is crushed and partially destroyed. The coal beds thus distorted are always subject to faults of the peculiar character described in the New England and New river coal fields, as well as those of Pennsylvania. Such faults are more frequently met with in the upper than in the lower beds of the latter. A fault is rarely met with in the great white-ash beds B, D, and E, except where they are inverted or seriously dislocated by the plicating movements. The dislocations of American coal beds are rarely vertical, and never to any great extent, as in the English fields, where this form of fault is peculiar. The nearest approach to this in the former is a “slip” which may slide one portion of a bed over the other, or remove it a few feet up or down. In the anthracite fields, however, faults are much more numerous than in the bituminous fields of England or the United States, but these are generally of the characteristic form peculiar to highly plicated strata before described. There are, however, other less frequent forms of fault, such as the occurrence of large areas of soft carbonaceous shale in place of the coal; long ribbon-like streaks of rock or slate in the coal from the top of the bed, apparently to fill a crack in the same; or the interposition of rock and slate between the strata of a bed, dividing it so as to render valueless sometimes one or both divisions. These faults do not affect the accompanying beds. The preceding are such as are strictly denominated faults in the Pennsylvania anthracite fields; but the ever-varying

dip of the strata, the change of strike incident thereto, and the general irregularities of both coal bed and accompanying strata, would be denominated faults in the great bituminous fields of the United States or England.—The use of anthracite as a common fuel is recent. It was long supposed to be an inferior kind of coal, and the creation of an earlier period than the true carboniferous; even now there are a few professional men who adhere to this exploded theory. The first attempts to use it as fuel were as a substitute for wood or the free-burning bituminous coals, where a draught of air through the mass is not absolutely necessary, as in the case of anthracite. On account of this difficulty of ignition, and the prevailing ignorance in regard to the best methods of using it, anthracite was slow to be appreciated. In 1813 it was considered inferior in Wales, and was but little used for any purpose; and though known and tested as a valuable fuel in the United States arsenal at Carlisle, Pa., in 1776, and by smiths on the Susquehanna generally even at an earlier date, it was only in 1812 that it was successfully used in Philadelphia, and there the mode of burning it was discovered by accident. The general trade only commences with a few tons in 1820. (See table.) At first the increase of consumption was slow, but so soon as its use and advantages became generally understood, it assumed the first place in the list of combustibles. For household purposes it is preferred not only on account of its cleanliness and the absence of smoke and the peculiar odor of bitumen, but also on account of its durability and long continued and uniform heat. For war steamers, where the conspicuous smoke of bituminous coal is exceedingly objectionable during hostile movements, anthracite has been fully tested and found superior, not only because of the absence of smoke, but of its good steam-producing qualities, its duration at high temperatures, and the consequent maintenance of a steady uniform steam power. For the economical combustion of anthracite a strong draught rather than an abundant supply of air is required. In common use, however, where chimney draught is ordinarily employed, these two requirements are antagonistic, as far as economy is concerned. To obtain a draught strong enough to pass sufficient air through the coals, a high and hot chimney is required, which absorbs and carries off the largest proportion of caloric from furnaces as commonly constructed. The coal is rarely burned to carbonic acid by direct combustion in this manner, but rather to carbonic oxide, which is lost, and more than half the fuel is thus wasted. The first or direct combustion, producing carbonic oxide, generates about 1300° C., while the carbonic oxide is capable of producing over 2100° C. of heat in addition; but when anthracite is burned to carbonic acid direct in properly constructed gas-burning furnaces, the temperature is increased to 2400° C. The volume of heat or total heating effect is, however, in favor

of carbonic oxide as fuel, and it would be much more economical and generally useful to convert anthracite or bituminous coal to carbonic oxide before using it as a fuel. In the blast furnace, however, where anthracite is preëminent, the coal must be used in its solid condition; but here, in well constructed furnaces, the total heating effect of the coal is utilized. But it cannot be claimed that anthracite is a superior fuel for all purposes, because bituminous coal can be used in all cases, while anthracite cannot be used in the present state of the arts for the production of illuminating gas. Where a long hot flame is required, as in puddling furnaces, hydrogenous coal is more available; and for welding heats, where hollow fires are desirable, the latter class of coal is also used. But under proper combustion, anthracite, as the purest form of carbon available for fuel, will yield a higher temperature than any other kind of fuel.—The earliest record of the use of anthracite for the production of iron is in 1826, when a small furnace built under the direction of Messrs. White and Hazard of the Lehigh coal company, near Mauch Chunk, Pa., was tried with anthracite and cold blast; but, though several pigs of anthracite iron were made, the furnace chilled and the attempt proved a failure. Several other experiments were made both on the Lehigh and the Schuylkill, which were successful in the production of anthracite iron, but failed of practical results. Attempts had been made prior to this time to use anthracite for the production of iron in the blast furnaces of Wales; but nothing definite is given in regard to the date of these experiments until after the introduction of the hot blast by Neilson in 1831, or its more general use in 1883. Mr. David Thomas then conceived the idea of using anthracite with hot blast, and induced his employer to try the experiment. A coke furnace was accordingly altered during 1836, and provided with a hot-blast arrangement; and in February, 1887, anthracite iron was successfully made in Wales for the first time. In 1837 the Lehigh coal and navigation company, attracted by the success of the Welsh furnace, sent one of their directors to Wales, who engaged Mr. Thomas to start a furnace on the Lehigh, which was successfully accomplished in June, 1839. The “Pioneer Furnace” at Pottsville, built by William Lyman of Boston, had been put in blast a few months previous, after the directions of Mr. Thomas. For this Mr. Lyman was awarded a premium of $5,000 which had been offered by Burd Patterson of Pottsville and Nicholas Biddle of Philadelphia for the profitable production of anthracite iron, and which was paid at a banquet given at Mt. Carbon early in 1840. Since then the Thomas and Crane iron works on the Lehigh have grown to mammoth establishments, and are now capable of producing 100,000 tons of pig iron per annum; and the total annual production of anthracite iron has now (1873) reached 875,000 tons.