# The American Cyclopædia (1879)/Coal

COAL, a black, opaque, inflammable substance, generally hard and compact, though laminated and stratified in beds between layers forming the crust of our earth. Coal has become one of the essential elements of modern civilization; in fact, the progress of the civilization of a country is now recorded by the amount of coal obtainable and employed by the inhabitants in a given time.—Mineral coal is a compound especially of carbon or of decomposed woody matter, with inflammable substances and hydrogen and oxygen gases. According to the different proportions of the volatile matter, in common language inaccurately called bitumen, the coal has a somewhat different aspect, flames more or less rapidly and actively, and develops heat in different degrees. These differences have served as a basis for a kind of classification of the coals, which, though scarcely limitable in its divisions, is generally admitted for common use. The more essential of these divisions are the following: 1. Anthracite or glance coal, a very hard, compact, lustrous, grayish black mineral, breaking in conchoidal fracture, though still bearing evidence of its original lamination. It burns slowly, with little or scarcely any flame, producing a high degree of heat. On account of the minute proportion of volatile matter in its composition, the coal is also called non-bituminous. When this coal is somewhat less dense, and has an increasing amount of volatile matter, it burns with more flame, and is then semi-anthracite. 2. Bituminous coal, though still hard, breaks more easily and more irregularly, often dividing into large cubic pieces in the plane of stratification and by cleavage. It is generally quite black, still with some lustre, contains less carbon with a larger proportion of inflammable substances than anthracite, and therefore takes fire more easily and rapidly, and burns with a bright yellow flame, developing less heat. The amount of volatile combustible matter in its composition is extremely variable, and therefore its appreciable characters, either in its value as a combustible material or in its appearance, vary in the same degree, considerably blending the classification and multiplying its names. With a moderate proportion of inflammable gases it is dry coal; with more bitumen it becomes fat coal, which passes to caking coal when in burning the matter softens and coalesces like paste. Of the moderately bituminous coals, the best known in America is called semi-bituminous, of which very large quantities are produced from the Cumberland district of Maryland, and the Broad Top, Clearfield, and Blossburg districts of Pennsylvania, along the S. E. margin of the Alleghany coal field. Of the more highly bituminous coals the most valuable is the splint or block coal of N. W. Pennsylvania, Ohio, and Indiana, which owing to its peculiar structure can be used in its raw state in the blast furnace. 3. Cannel coal is also a kind of bituminous coal. It differs much from the numerous other varieties by its fine, equal, compact, homogeneous texture, resembling a dusky black paste hardened to a mineral substance or to stone. It breaks therefore with a conchoidal fracture, and is at once distinguished from the other kinds of bituminous coal by its equal, non-laminated structure, or the absence of those horizontal thin layers which in the common kinds of bituminous coal are seen alternating in different degrees of lustre and apparent density. By distillation it yields a larger proportion of mineral oil than any other coal. Sometimes it is so highly bituminous, as in the case of the Breckinridge coal in Kentucky, that it is dangerous to use it in steamboats, or in grates through which the oil percolates when inflamed. It burns like candles, and hence its name.

ANALYTICAL TABLE OF MINERAL FUEL.

No.  NAME AND LOCALITY.  Density.   Free Carbon.   Total Carbon.   Hydrogen.   Oxygen.   Water.  Ash.

1  Peat, general .... .... 28.09 5.93 30.37  30.05  5.62
2  Lignite, Rocky Mts. 1.230 24.00 64.99 3.76 16.42  10.56  5.27
3  Anthracite, Rocky Mts. 1.300 ? 74.37 2.58 10.00  5.20 7.88
4  Cannel coal, W. Va. 1.300 23.00 82.00 5.16 8.04 2.25 2.55
5  Block coal, Penn., W. Va., O., Ind.  1.275 *30.00  82.92 6.09 10.00  2.00 1.49
6
 ${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}}$ Caking coal, general Caking coal, rich gas
 ${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}}$ 1.400 1.350
*15.00  85.90 5.46 5.00 2.00 1.64
25.00 84.00 6.00 5.00 3.00 2.00
7  Hard anthracite, Penn. 1.550 ? 94.00  .40 1.26 2.30 2.50
8  Soft anthracite, Penn. 1.450 ? 87.00 2.50 3.50 2.00 4.00
9  Dense anthracite, New England 1.780 .... 80.00 .... .... 10.00   10.00

—If the more marked characters which indicate the several species of mineral coal are easily recognized at first sight, and if everybody knows the bituminous coal from the anthracite or the cannel, it is not the less certain that, considering the matter in itself and in its compounds, coal is an indivisible whole. Not only have all the kinds of coal the same constituent chemical elements, merely varying in proportion in a slight degree, but all the varieties of coal, of bituminous especially, are found in some localities in the same vein. Anthracite passes to semi-anthracite, and this to bituminous coal, by inappreciable degrees. The coal beds of Shamokin and Trevorton in Pennsylvania give anthracite and semi-anthracite. The Spadra coal of Arkansas is semi-anthracite at one place and bituminous at another. In Kentucky some veins have one half of their thickness bituminous, the other half cannel; or at other localities, as for example on the Louisa river, the miners work bituminous laminated coal at one end of a gangway and cannel at the other, and this in the whole thickness of the bed. The analysis of caking coal fails to show any difference even in the proportion of the constituent elements from that of some kinds of dry or non-caking coal. Indeed, the character of the coal, where closely examined, is constantly variable in the same bed at the same mine, even upon the same square foot of matter, as recognized from specimens when taken at the same place from the roof to the bottom of the bank, although little or no difference is observed in a large quantity as it comes from the mine.

ANALYSIS OF CANNEL COALS.

 LOCALITY. Sp.grav. Volatile matter. Fixed carbon. Ash. Albert coal, New Brunswick 1.129 61.74 36.04 2.22 Boghead cannel (Scotch) .... 66.35 30.88 2.77 Grayson, Ky., “jet cannel” .... 61.95 30.07 7.98 Grayson, Ky.,  cannel 1.371 62.03 14.36 23.62 Breckenridgen, Ky., cannel 1.150 64.30 27.16 8.48 Torbane hill cannel 1.189 67.11 10.52 21.00 Boghead black cannel 1.218 62.70 9.25 26.50 Boghead brown cannel 1.160 71.06 7.10 26.20 Hardie's (Scotch cannel) 1.420 53.70 4.90 38.80

FORMULA OF THE GENERAL VARIETIES OF COAL.

 Constituents. Anthracite. Caking coal. Cherry or  Block coal. Splintcoal. Cannel coal. Lignite. Carbon 92.56 87.952 83.025 82.924 75.25 64.00 Hydrogen 3.33 5.239 5.250 5.491 5.50 5.00 Nitrogen ? ? ? ? 1.61 ? Oxygen 2.53 3.806 8.566 8.847 13.83 26.00 Ash 1.58 1.393 1.549 1.128 2.81 4.00

In order to understand more easily the distribution of the combustible minerals, especially coal, it is convenient to have for reference a tabular section of the American geological divisions from the earliest times till now, as they have been recognized by science. The following brief review of the formations, from the lowest or oldest to those of our own time, has special reference to such evidence as they show of coal or any combustible mineral resembling it.—No trace of remains of either plants or animals has been positively recognized in the lowest formations of the earth, which, composed generally, at least, of crystalline metamorphic rocks, are considered as the result of the cooling of the surface of our planet, which was originally in a state of fusion or of vapor. The archæan rocks, also called primitive rocks, are therefore the only ones universally formed, all the others depending upon local abrasions for their materials, which, transported and deposited mostly by water, are local in their distribution. Animal life is now, and must have been from the beginning, dependent upon vegetable life as the only source of its food. The first traces of organic remains should for this reason represent plants. The primitive or archæan formations have deposits of graphite or plumbago, a matter essentially composed of carbon. It is not known as yet how this matter has been produced or whence it is derived. It has been and may be ascribed to vegetable and animal life, represented at its beginning by beings of very simple soft texture, like the confervoidal filaments which at our time live in thermal springs, filling basins of water of the temperature of the boiling point mixed with animalcules or infusoria. The remains of these plants and animals could not have been preserved, or at least could not be discovered, in the crystalline matter of the primitive rocks. The presence of graphite in the carboniferous strata of Rhode Island, and the close likeness of some beds of anthracite of this basin, which in some of its veins is scarcely distinguishable from graphite, point to vegetables for the origin of this substance. For even the hardest layers of anthracite or graphite of Rhode Island bear well preserved remains of plants of the carboniferous period, and evidently their carbon has been derived from vegetable life. The graphite of the primitive rocks, however, like the crystalline matter, granite, mica, hornblende, syenite, &c., may be due to some as yet unknown combinations of the primitive matter of our globe. The primordial or Cambrian period is subdivided into two epochs: the upper, called the Potsdam, and the lower, the Acadian epoch. In this last formation the first remains demonstrating vegetable life appear in some fucoids or marine plants of undefined forms. They become more numerous and more distinct in the Potsdam sandstone, in which large species of algæ have been obtained and described. Their size indicates already a high degree of organized life. In the Canadian period, especially in the calciferous limestone which constitutes its lowest division, these fucoidal remains increase in abundance, representing many more species, and the rocks where the remains are imbedded are often discolored by what appears to be an impregnation of mineral oil. The matter is however very sparingly distributed. But in the Trenton period, from its lowest division, the Trenton limestone, to the Cincinnati, its upper epoch, the marine vegetation is evidenced not only in an abundance of petrified plants, but in local deposits of mineral oil, especially found in connection with a predominance of fucoidal remains, which thus attest one of the wise purposes of their life in the great plan of nature. The Hudson shales give mineral oil sparingly; the Cincinnati limestone has yielded it abundantly; the black Utica shale of the same period has sometimes from 12 to 20 per cent. of mineral oil; but no trace of coal has been found in the rocks of the Trenton period. The three divisions of the Niagara period, the Niagara, the Clinton, and the Medina, have also, in their shales, limestones, and sandstones, a prodigious abundance, in some localities at least, of marine plants. In Pennsylvania the Clinton ferruginous red shale is covered over wide surfaces with these kinds of vegetable remains, together with a proportionate number of remains of

TABLE OF SEDIMENTARY STRATA, AND THE PLACE OF COAL AMONG THE ROCKS.

English equivalents. Pennsylvania. Nomenclature. Maximum and
minimum
thickness.
New York. Missouri and Illinois. Maximum and
minimum
thickness.
minimum
thickness.
REMARKS.

 NEOZOIC. ${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}}$ Recent.
Drift, &c. ?  Pennsylvania  Penn. and N. York ?  Drift, &c. 150 ?
Tertiary  Absent ?  Tertiary, no coal 200  Tertiary coal
Cretaceous  Absent ?  Absent 0  Cretaceous
Oölitic  Absent  Absent  Absent 0  Oölitic
Triassic  Absent  Absent?  Absent 0  Triassic
Permian  New red sandstone  New red sandstone  Absent? 0  Permian

250 to 1,500 250 to 1,000 ? 800 to 500 1,000 to 1,500

Containing lignite coal beds. Limestones and red sandstones. Richmond, Va., coal. Not investigated in the west. Containing gypsum, marls, &c., in Kansas and Colorado. Magnesian limestone.

PALÆOZOIC.

Carboniferous.

Coal measures Millstone grit Carboniferous limestones Sub-carboniferous

Coal measures Conglomerate Red shales White sandstones

XIII. XII. XI. X.

500 to 8,000 100 to 1,500 0 to 2,000 200 to 2,000

Absent Absent Absent Gray and white sandstones

Coal measures Millstone grit Carboniferous limestones

1,000 to 8,000 10 to 100 150 to 750

Concealed in Colorado by the tertiary. Occasionally seen in Colorado and Dakota.

Devonian

Old red sandstone. Eifel Eifel Ludlow

Red sandstones Limestones and shales Bituminous black slates Slates and sandstones

IX. VIII. VII. VI.

0 to 5,000 1,000 to 7,000 600 to 1,000 100 to 1,500

Catskill Chemung, Genesee, &c. Corniferous, Onondaga, &c. Oriskansy, sandtone, &c.

Bituminous slates, shales and limestones Oriskany

300 to 500 0 to 50

Not seen

?

Concealed or wanting in the far west.

U. Silurian

Marls, shales and limestones Medina sandstones

V. IV.

1,000 to 4,000 200 to 2,500

Saliferous, Niagara, &c. Medina sandstone, &c.

300 to 700 ?

Not seen

?

Cambrian.

Bala rocks Festiniog group Lingula flags

Slates and limestones Limestones Slates and Potsdam sandstone

III. II. I.

500 to 2,500 1,000 to 6,000 1,000 to 4,000

Slates and limestones Limestones Calciferous Potsdam sandstone

Galena and magnesian limestones and calciferous sandstones Potsdam sandstone

300 to 1,000 100 to 250

Galena and magnesian limestone Potsdam sandstone

? 50 to 250

Occasionally seen in Colorado and Dakota, but generally concealed by the tertiary, &c.

Gneissic

Gneissic

5,000 to 10,000

Huronian gneissic

(Ozark) gneissic

500 to 1,000

(Rocky Mts.) gneissic

 SUBSTANCES. Carbon. Hydrogen. Oxygen. Wood 49.66 6.21 43.03 Lycopodium dendroideum 48.70 6.61 43.25 Lycopodium complanatum 48.43 6.61 43.02 Equisetum hyemale 47.50 6.68 44.49 Sphagnum 49.88 6.54 42.42 Peat 59.5 5.5 33.0 Brown coal or lignite 68.7 5.5 25.0 Bituminous coal 81.2 5.5 12.5 Anthracite 95.0 2.5 2.5

This table shows in lycopodium species and equisetum about the same composition as in wood. These correspond in structure, and have at the same time a generic relation to the species forming the essential compounds of coal as recognized by microscopical examination, viz.: lepidodendron, sigillaria, and calamites. The sphagnum, which enters more than any other plant into the composition of peat, has more carbon than lycopods, even slightly more than wood. In the decomposition of the woody matter two different processes are recognized by chemistry. Decayed wood taken from the interior of trunks of dead trees exposed to atmospheric action gives by analysis, on the average, carbon 47.62, hydrogen 6.18, oxygen 44.87; which compared with wood, C. 49.66, H. 6.21, O. 43.03, indicates that through this decomposition a proportion of carbon has been taken from the wood, while the hydrogen is slightly increased. The elements of water therefore, and an amount of oxygen, have become united with the wood, while carbonic acid has been separated from it. This comparison of analyses exemplifies the well known fact that the decomposition of plants under atmospheric influences returns to the atmosphere the carbonic acid absorbed by the vegetation, which by nutrition of the living plants is transformed into wood. But when the woody matter is protected against the action of the oxygen of the air, as it is in vegetable remains under water or covered by mosses impregnated with water, the chemical changes as proved by analyses assume another form. This is the case in the formation of peat, which when ripe has C. 59.5, H. 55, O. 33, or compared with wood an increased amount of carbon in proportion with a diminution of oxygen, separated into carbonic acid with a little of the hydrogen of the wood. The amount of carbon in peat, as in all the mineral combustibles, is extremely variable; in young sphagnum peat it is no more than 51 to 52 per cent., while in old peat it is as high as 61 to 62 per cent. The proportion of bitumen increases in peat in the same degree. Taken from old beds, this matter has yielded by distillation 30 per cent. of bitumen. To obtain it, the distillation of peat has been practised for many years on the bogs of the Jura in Switzerland; and peat from the bogs of Ireland is also distilled in large establishments for manufacturing candles. This sufficiently answers the objection made against the theory of the formation of coal from heaped vegetables by annual growth like beds of peat, and the mistaken assertion that peat has no bitumen and therefore cannot form coal. The composition of peat as given above does not differ much from that of the more recent lignite of Germany, showing therefore the same process of chemical action. These lignite beds, mentioned before, are heaps of trunks overlaid by thick strata of sand and clay. The wood is black and quite soft, but its texture is still as well preserved and as distinct as in living trees. The matter in its purity has C. 57.28, H. 6.03, O. 36.10, or a less amount of carbon than old peat, with more oxygen; thus proving that the process of decomposition is exactly the same, but that it is in a less advanced stage. In lignite of an older formation the analysis indicates C. 68.7, H. 5.5, O. 25; therefore an increase of carbon, still resulting from the same combination, the diminution of the oxygen and of a little of the hydrogen of wood. As in peat, the amount of carbon in lignite is very variable, which results especially from the nature of the original compounds. The lignite of the old tertiary of the Rocky mountains, which in many beds has the same appearance, lamination, and nearly the density of the true coal, has only 51 per cent. of carbon in an average taken from the comparison of 21 analyses of the matter from many localities. This reduced amount of carbon is apparently due to the great proportion of palm wood and palm remains which entered originally into its composition. The average composition of the best qualities of bituminous coal is C. 81.2, H. 5.5, O. 12.05; showing still the same proportion in the diminution of the oxygen and the increase of carbon. The chemical action is therefore constantly the same, and is recognized in the whole process; that is, the slow combustion of the woody matter by the action of the oxygen which it contains, or contained originally. Chemistry has not perfectly explained the process, or obtained similar results and products by its experiments. Prof. Dana says that the changes attending the ultimate decomposition of woody matter into coal depend: 1, on the affinity of the carbon for oxygen, making carbonic acid; 2, on that of hydrogen for oxygen, producing water; 3, on that of carbon for hydrogen, making carbo-hydrogen gas or oil; and 4, on the tendency of the carbon and the hydrogen under certain proportions to form with a portion of oxygen the staple compounds included in the term coal. In anthracite the amount of carbon is still increased, while that of hydrogen and oxygen has become proportionally less, and the volatile matter is reduced to a minimum. Hence pure anthracite is debituminized and burns without any flame. The anthracite of Pennsylvania becomes harder and more free from gas in proportion to the distance of the basins eastward from the Allegheny mountains, where its beds are folded in more numerous and sharper flexures. It has been supposed that its debituminization had taken place from some cause connected with the uplifting of the mountains. The first supposition was that the coal had been reduced to anthracite by heat. This opinion has been contradicted by another hypothesis which ascribes the transformation to great compression of the mineral coal by the upheaval of the mountains between whose sides the basins were slowly pressed, and thus slowly forced into numerous folds, and perhaps to a considerable amount of caloric produced by mechanical agency, movement, compression, &c. Many facts seem to contradict this last hypothesis, and support the opinion that the original heat of the earth has contributed to the metamorphism of the coal, as it has to that of the rocks. The problem is however complex, and cannot be discussed in a few words. The facts have to be recorded, and the conclusions may become evident in time. In Pennsylvania the debituminization decreases in proportion to the distance eastward from the mountains. At Trevorton, in Zerbe's gap, the coal is semi-anthracite; it has 84 to 86 per cent. of carbon, 7.50 of inflammable gas, and 2.50 of water. Though this basin is far distant from the mountains, the undulations of its beds are nearly as sharp as those near Pottsville and Tamaqua, being inclined at an angle of 50° to 60°. As the thickness of the strata is great, the pressure seems to have been equal to that nearer the mountains. In the Rhode Island basin the anthracite is still harder and more debituminized. Here the undulations are repeated, very numerous, and short, but not sharp, resembling the waves of the sea, and the strata are not thick; but the anthracite is in close proximity to the primitive rocks, and the shales over and under the coal show by their color and density the evident traces of metamorphism. There is here a peculiar phenomenon marking the influence of heat; it is the liquefaction of the shale and the effects of it on the vegetable remains, particularly the ferns. Their branches are generally elongated in one direction and contracted in the other side, as though drawn to one direction by the flexure of the shales in a state of semi-fusion. The plants too bear upon their surface a kind of intumescence, seemingly produced by heat. At Trevorton the shales over the coal are more or less marked by small round holes varied in size, filled with a pulverulent bituminous matter which looks as if formed by a kind of ebullition, or rather by gas forcing its way from the anthracite and stopped and enclosed within the shale. In Arkansas the Spadra coal is semi-anthracite. The strata wherein it is interlaid are nearly horizontal, their dip scarcely marked by an angle of 2°. It is also at a distance of 30 m. from the mountains. It has about the same composition as the Trevorton coal, 88.75 per cent. of carbon, with 7.7 of volatile matter. The rocks all around in the country bear traces of metamorphism, and the change by heat becomes more and more evident in advancing toward the Hot Springs, a volcanic region, away from the mountains. The same phenomenon is still more evident, and its cause more appreciable, in the tertiary lignite basins of the Rocky mountains. At Golden, Colorado, the thick lignite beds, 12 to 16 ft., are thrown up to the perpendicular by compression, in close proximity to the base of the uplifted granitic mountains, and between them and thick deposits of lava. This coal is soft, bears no trace of metamorphism, and even crumbles from the contact of the atmosphere. In New Mexico the strata are horizontal, but split by thin dikes of basalt, along which the coal shale is changed by heat and nearly as hard as silex. The nature of the coal in contact with these dikes has been recorded from a locality further south, near the valley of the Gallisteo, where the Placiere coal at one exposure of the bank is true lignite, while at another exposure, and in contact with an enormous dike of basalt, it has been changed into true anthracite, having 89 per cent. of carbon and only 3.18 of volatile matter, while at a distance from the dike the amount of carbon is only 58 per cent. The dip of the strata even in coming closely in contact with the dikes varies between 10° and 14° only. These facts are evident proofs of the debituminization of the coal and its change to anthracite by the action of heat. In this we have at the same time an insight into the chemical changes causing the modification of vegetable matter and its transformation into coal. For the action of heat does not deprive the coal of any part of its constituents; it merely quickens the slow burning or metamorphosis of the matter, the ultimate result of which is the entire reduction of the oxygen- and hydrogen-producing volatile gas into compact or condensed mineral combustible, a mere compound of the original elements of wood modified under peculiar influences.—The great Alleghany coal field extends from the middle of Alabama to northern Pennsylvania, and occupies portions of Alabama, Georgia, Tennessee, Kentucky, West Virginia, Virginia, Ohio, and Pennsylvania. It contains from 50,000 to 55,000 sq. in. of coal area, and all the coal beds and groups of beds described under the title Anthracite, the nomenclature of which will be adopted herein. In some portions of the anthracite fields the millstone grit or conglomerate is interstratified from the bottom to the top of the coal measures, though much more massive near the bottom than in any other portion. It is also much thicker in the eastern part of these fields than in the western portion, and likewise more massive than in the bituminous fields, or westward generally, as the foregoing table indicates. A group of coal beds, O, not shown in the anthracite column, though existing there as “nests” of imperfect coal below A, are found
A, or Alpha
at irregular intervals throughout the Alleghany coal field; but these beds are thin, impure, often absent, and rarely of workable size or merchantable quality. They exist both below and in the millstone grit when found, and are more persistent and regular in the western than in the eastern coal fields. The first group of regular beds is A; these also exist in the conglomerate in the Pennsylvania anthracite fields, and in some of the outlying basins of the Alleghany field; but generally they consist of two small, unworkable streaks of impure coal, or a single bed of earthy coal 1 to 4 ft. in thickness, resting on or near the millstone grit. It produces the block or
B, or Buck Mountain.
furnace coal of Pennsylvania. The next group, B, consists of two regular and excellent beds, which are generally united as a single bed, though always divided by a streak of slate or fire clay, which often expands to 20 ft. or more. This bed, or group of beds, is the most regular of all the American coal beds; and, being the first large, workable, and productive bed, its horizon is the most extensive, and nearly equal to the area of the entire field, while it can readily be identified in the central if not the western coal field. These beds, when united, are from 4 to 7 ft. thick, and singly from 2 to 4 ft. each. Immediately above this group, sometimes resting on the coal, but generally separated by slates and shales, is the micaceous sandstone, or “buckwheat rock” of the Pennsylvania mines, which is a coarse, massive sandstone, filled with mica scales. This rock is very persistent, and can be identified in all the great American coal fields of the carboniferous age. This great bed of sandstone, which is often 20 to 60 ft. in thickness, is followed by shales and the fossiliferous or ferriferous limestone, and the
C, or Gamma.
buhrstone iron ore, which are generally present in the Alleghany coal measures. The ore ranges from 10 to 20 in., and the limestone from 10 to 20 ft. in thickness. This is succeeded by shales and the group of coal beds.C. In the anthracite regions, and generally in the bituminous fields, this group consists of two thin, slaty, and
D, or Skidmore.
unworkable beds; but one of them frequently expands to 3 and even 5 ft. of excellent splint or cannel coal. It is the celebrated Peytona cannel bed of Coal river, West Virginia, and the Grayson cannel of Kentucky. This group is succeeded by shales and sandstones of variable thickness, from 50 to 150 ft., on which rests the bed D, which is always single, and generally pure and workable, from 30 in. to 4 ft. in thickness. Above this bed, separated by
E, or Mammoth.
sandstones and shales, is the Curlew or Freeport limestone, 8 ft. thick; and on or near this rests the group E, which embraces two or three beds of coal, each generally from 2 to 4 ft. thick, which often unite as a single bed of 6 to 12 ft., divided by slates. This group forms the celebrated mammoth bed in the Pennsylvania anthracite fields, and the Freeport beds in the western part of Pennsylvania. Above this group (which is very confusing to the miner and the geologist, on account of its irregularity and uncertainty in uniting and dividing) from 20 to 50 ft. of soft black shales or slate are generally found, and on these rests the Mahoning or mammoth sandstone, which is the largest regular sand rock in the Alleghany coal measures, ranging from 50 to 75 ft. in thickness, divided by one and sometimes two thin coal seams, and several feet of slates or shales. Streaks of quartz crystals are often found between the upper and lower strata of this great rock, which is a quartzite, and often a conglomerate rock, 80 ft. thick in the anthracite measures. It is sometimes accompanied by a stratum of white quartz secretions,
F, or Holmes
or conglomerate, even in the western portions of the field, which are often mistaken for water-worn pebbles. This is a great landmark in the Appalachian coal fields, which cannot well be mistaken, and yet it is often misplaced. Above this exists the group F, which consists of two thin impure beds, divided by a few inches of fire clay, known as the rough bed in the anthracite fields, where it is 5 to 7 ft. thick, and as a single bed in the Allegheny field, 1 to 2 ft. thick of slaty and sometimes 3 ft. of cannel coal. It seems to be a true horizon of coal, but is seldom found in merchantable quantity or quality. Above these are from 200 to 300 ft. of shales, slates, sandstones, and limestones, followed by the bed G, which is the large and celebrated Pittsburgh bed, remarkable for its production of excellent gas, coking, steam, and household coal, combining all the qualities of every variety of bituminous coal except the block and cannel. It ranges from 6 to 12 ft. in thickness, averaging from
G, or Primrose.
6 to 8. Between these great beds, E and G, exist from 300 to 450 ft. of unproductive strata, which contain no workable beds of coal. These are known in Pennsylvanian nomenclature as the lower barren measures, which are as distinctly marked in the anthracite as in the bituminous fields of this state. It may be briefly stated that all the coal beds and coal measures existing in the anthracite fields above G are found in some portions of the Alleghany field; but the coal beds are thin, rarely workable, and cannot be identified. From 1,000 to 2,000 ft. of coal measures are supposed to exist above G; but these are known as the upper barren measures, and are made up chiefly of shales, with a few coarse sandstones and massive limestones, one of which is 70 ft. in thickness, and is distinctly defined over a large area. The general average thickness of the coal measures between B and G is 1,000 ft., but varies from 500 to 1,200 ft. From the carboniferous limestone to B, including the groups O and A, the thickness of the strata is from 200 to 500 ft., and the total thickness of the coal measures about 3,000 ft. in Pennsylvania, with a minimum thickness of 30 ft. and a maximum of 50 ft. of coal.—The distribution of the deposits of coal in North America, is well adapted for the supply of the wants of the present inhabitants. The largest population is along the Atlantic coast, and the best coal, that of the anthracite fields of Pennsylvania, happens to be situated nearer the largest markets than any other, being less than 200 m. from New York and less than 100 m. from Philadelphia. The basins producing it are small, containing in all but 470 sq. m.; but the beds are very large and numerous, and the quantity produced is about half of all the coal mined in the United States. (See Anthracite, Lackawanna, and Wyoming Valley.) In the eastern central part of Pennsylvania, where the anthracite basins are situated, great disturbances of the strata have taken place after they were deposited, caused by the gradual upheaval or subsidence of alternate portions in N. E. and S. W. lines, so as to throw them into a waving form. This disturbance was greatest toward the S. E., and the rock arches become wider and flatter as we go N. W.; but they extend S. W. entirely across this state and Maryland, and their effects are even seen in the coal field of eastern Ohio. All anthracite coal is found in regions where the strata have been considerably disturbed, or where from local causes it has been subjected to heat. Next westward from the anthracite in Pennsylvania the coal is semi-bituminous, and still further west it is of the ordinary bituminous character, the quantity of volatile matter constantly increasing toward the central part of the field. The carboniferous formation terminates in the northern part of Pennsylvania, and the division into counties of that district happens to correspond with six of the great flexures of the strata before mentioned, which give rise to six coal basins. Some of these from their far northern position contain some of the richest and most productive mines in the state. They produce, for the supply of the coalless country north of them, the variety commonly called Blossburg, which is used for steam and manufacturing purposes. The deposits of coal extend in this northern district along the middle or bottom of the basins only, in lines of small detached fields or chains of basins, which are more extensive as they are followed S. W. until they become uninterrupted prongs or finger points. Still further S. W. in Pennsylvania the lower beds arch over portions of the intermediate anticlinals, and in the S. W. part of the state, in the Pittsburgh country, the four or five lower beds which alone occur further N. disappear on the surface, dipping under a red and gray shale formation in which are no coal seams. Above these barren measures in the highest ground about Pittsburgh appears another bed of excellent coal, named after that city, from which all the coal is mined that is used in the S. W. part of the state, large quantities of it being also sent down the Ohio and Mississippi rivers. Pennsylvania not only supplies the United States with all the popular fuel anthracite, but she also produces more bituminous coal than any other state, of which she has every variety of excellent qualities. The northern districts in 1873 produced 1,500,000 tons, and the eastern margin of the field 1,000,000 tons of semi-bituminous coal. Of the common bituminous coal 9,000,000 tons were mined in that year, chiefly in the Westmoreland and Pittsburgh districts and along the Monongahela and Youghiogheny rivers, for the supply of all the western states by way of the Ohio and Mississippi rivers, for gas making in the eastern cities, and for domestic and manufacturing purposes in the state. This is therefore the greatest of all the coal-producing states; and from its geographical position, its rich endowment of other minerals, and other natural advantages, there is every probability of its continuing to retain this position for a long time. The coal field which covers the eastern part of Ohio is the western border of that of western Pennsylvania. It stretches along the Ohio river from the Mahoning river on the north to near the Scioto on the south, from two to four counties in width, embracing 10,000 sq. m., being nearly as large as that of Pennsylvania, which has 12,774 sq. m. of coal. Along the N. E. border is found a peculiar splint or block coal, which has been used for many years in its raw state in blast furnaces; some small basins of it also occur on the Pennsylvania side of the line. Further south, in the Hocking valley, occurs a coal bed of extraordinary size, measuring in some localities 12 ft. in thickness, and it is said that it can also be used like the block coal.

 Fig. 5.—Appalachian Formations, Ancient and Modern. References: Modern.—a, the Atlantic sea; b, recent or cretaceous formations; c, granitic and volcanic; d, mesozoic, new red, &c.; e, metamorphic, gneissic, &c.; g, sandstones and limestones of the valley, or the lower palæozoic formations; h, slates and shales of the oil-producing formations; i, sandstones overlying the oil strata, including the old red and the conglomerate; j, the anthracite coal deposits; k, Cumberland coal field; l, l, n, Alleghany coal field; m, Ohio river. The Potsdam sandstone underlies the Auroral limestone, g, and overlies the gneiss, e, which must exist to some extent in the entire basin. The dark vertical trap formations emerge from the granite, and were the means of forming the gneiss. Ancient.—No. 1 corresponds to a, and is the granite seacoast line, forming the volcanic boundary of the ancient sea; 2 is a deep view of the volcanic vent between the granite and the gneiss, which is formed of the vented matter; 3 is the metamorphic or early gneissic sedimentary rocks; 4 corresponds to g, and is the base of the palæozoic; 5 is the bituminous slates of the oil strata, followed by the massive sandstones of the old red, and the subcarboniferous; 6 is the ancient sea, since filled by the sedimentary deposits represented in g, h, i, j, k, l, &c.; 7, 7 is the line of volcanic vents existing in the plutonic or granitic coast line, which extends from Maine to Cuba. The form of the ancient structure is of course ideal, and the two views are thus given together in order to convey an impression of the cause and its effects.

The production of coal has not been very large in Ohio (about 4,000,000 tons), but from the building of railroads, and the increase of population and manufacturing, the coal trade of the state is rapidly increasing. Maryland has a very small but very valuable basin of bituminous coal near the Baltimore and Ohio railroad, extending from near Cumberland to Piedmont in the western angle of the state. The production in 1873 was 2,674,110 tons, and since the opening of trade in 1842 the total production has been 24,027,786 tons. It is sold chiefly at New York for the use of ocean steamers and other steam purposes, is known as Cumberland coal, and is semi-bituminous; the bed is 14 ft. thick. West Virginia is almost wholly underlaid with bituminous coal, forming a portion of the same field above described in Pennsylvania, Ohio, and Maryland. The upper coal measures, including the Pittsburgh bed, extend over a large space in the N. W. part of the field in this state, along the Ohio river, as far south as the mouth of the Guyandotte. In the northern part of the state these upper coal beds are developed of good size and quality along the Baltimore and Ohio railroad and on the river about Wheeling. There are very fine natural exposures of the lower coal measures on the Kanawha river, from the great falls to Charleston. The display of coal in this district is very remarkable, and it has recently been made accessible by the completion of the Chesapeake and Ohio railroad. There are other very extensive districts in West Virginia, both N. and S. of the Kanawha, where there is known to be a great abundance of excellent coal in localities to which no railroads have been built. There is little or no doubt of the identity of the coal beds throughout the states of Pennsylvania, Ohio, Maryland, West Virginia, and eastern Kentucky, which shows a wonderful sameness in distribution throughout all this vast territory. This coal field extends over the eastern part of Kentucky, and in the northern part of it in this state the Ohio and West Virginia coal beds of the lower series are found, but in the southern counties of the field only the subconglomerate coal beds appear. Very little development has taken place in this district, except on the Ohio river. Tennessee has an interesting and valuable coal field, which is coextensive with the table land of the Cumberland mountain, forming the western boundary of the valley of East Tennessee. In the more northern part of it the lower coal measures of the states further north seem to be found, but the great body of the field is composed of the coal beds still lower in the series which are found in West Virginia and eastern Kentucky. The conditions for coal making appear to have existed in the south earlier than further north; consequently coal is found in rocks which in the north are subcarboniferous and produce no coal. Alabama has the southern extremity of the great coal field we have been describing, divided into three separate portions called the Black Warrior, the Catawba, and the Coosa fields, containing in all 5,330 sq. m. Some of the best deposits of iron ore in America are east of and in the immediate vicinity of the coal fields of Alabama, Tennessee, and West Virginia, which at some future time will make this the seat of large iron manufactures. Thus far, however, but little has been done to bring into use these vast treasures of fuel. This first, Alleghany, or great eastern coal field of the United States, containing in all 58,737 sq. m., is by far the best and in all respects the most important in America.—When the first geological researches were in progress in the western states, it was supposed that the coal beds and the series of coal-bearing rocks were the same in Illinois, Indiana, and western Kentucky as in Pennsylvania, but it is now proved that they are entirely different and never were connected. The recent geological survey of Ohio shows that the great anticlinal axis which passes from Lake Erie past Cincinnati and through the eastern parts of Kentucky and Tennessee is much older than the coal-making age, and that the coal fields of Michigan and Illinois were always separated by it from that of Ohio. The peninsula of Michigan contains a coal field of 6,700 sq. m., extending from Jackson to Saginaw bay, but the coal-bearing rocks are only about 100 ft. thick, and contain but one bed of coal of about 3 ft. or less of coal of a bad quality, full of sulphur and other impurities, and the annual production is small. The materials of its rocks were derived from the north. The third great coal field covers 6,500 sq. m. in the western part of Indiana, 36,800 sq. m. in Illinois, and 3,888 sq. m. in the western part of Kentucky. The best coal produced in this field is from Indiana, where along the eastern border of it there is a good quality of block coal for furnace use, and some common bituminous coal of fair quality. The Illinois coal is all much inferior to that of Pennsylvania and Ohio, contains a portion of hygrometric moisture which lessens its heating power, and considerable sulphur and other injurious impurities. Notwithstanding this, it is invaluable to the state, which is almost wholly a prairie country, mostly level, destitute of trees, covered in a state of nature with tall coarse grass, and with an extremely fertile soil. The want of fuel of any kind would have been a great disadvantage; and inferior as it is, considerable quantities are annually produced in many parts of the state, especially opposite St. Louis and near other large places. The portion of this field extending into western Kentucky is believed to contain better coal than that of Illinois, and it now produces moderate quantities from mines near the Ohio river.—The fourth great coal field lies west of the Mississippi river, in western Iowa, southeastern Nebraska, northern Missouri, eastern Kansas, the Indian territory, and western Arkansas, and possibly it underlies the cretaceous formation which on the surface separates it from the Texas coal at Fort Belknap; it contains in all nearly 80,000 sq. m. The deterioration westward of the coal continues over this field also, there being fewer and thinner coal beds and coal-bearing rocks, the latter becoming gradually converted into vast beds of limestone, and the shales and sandstones among which coal is usually found becoming subordinate. The best and most productive portion of this field is the district in Iowa along the Des Moines river. In S. W. Iowa and N. W. Missouri, in Nebraska, and the western border of the field in Kansas, the upper coal measures, a great limestone formation very similar to the subcarboniferous limestones below the coal, comes in, containing only one or two very thin beds of coal about one foot thick. The middle coal measures are but little better, the valuable coal beds all being found in the lower coal measures. On the Des Moines river are some beds of fair size, and there is a considerable production. In Missouri, where the lower coal measures are exposed in a district containing 12,420 sq. m., extending from the Iowa line in the N. E. part of the state S. W. across the Missouri river to the Kansas line near Fort Scott, there are workable beds from 2 to 3 ft. thick, and in the absence of better fuel there is local demand for a considerable quantity of the production. This productive coal belt extends into the S. E. corner of Kansas, whereas in the other parts of the state where the coal extends the seams near the surface are only about one foot thick. The dip of this coal field is toward the northwest, and on its western border Permian fossils are found, this being the only locality where that formation has been found on this continent.—According to the United States census, the statistics of coal production for the year ending June 1, 1870, are as follows: Number of collieries, 1,566; hands employed under ground, 65,000; above ground, 29,854; total, 94,754; capital employed, $110,008,029; wages paid,$44,316,491. Bituminous coal mined, 17,199,415 tons; value, $35,029,247. Anthracite coal mined, 15,664,275 tons; value,$38,495,745. Total coal mined, 32,863,690 tons; value, $73,524,992. The distribution of the production of coal in the United States in the chief coal-producing states is shown in the following statement from the census of 1870. Except in the case of Pennsylvania, the production is bituminous coal:  STATES AND TERRITORIES. No. of collieries. CapitalInvested. Tonsproduced. Value ofproduct. Alabama 2$26,000 11,000 \$39,000 Illinois 322 4,288,575 2,624,163 6,097,432 Indiana 46 554,442 437,870 988,621 Iowa 96 618,332 263,487 874,334 Kansas 20 166,430 32,938 114,278 Kentucky 30 717,950 150,582 446,792 Maryland 22 23,891,600 1,819,824 2,409,208 Michigan 3 176,500 28,150 104,200 Missouri 56 2,587,250 621,930 2,011,820 Ohio 307 5,891,813 2,527,285 5,482,952 Pennsylvania 588 67,911,703 28,448,793 52,357,814 Anthracite 227 50,922,285 15,650,275 39,422,775 Bituminous 361 16,989,418 7,798,518 12,985,039 Tennessee 11 313,784 133,418 330,498 Utah 6 44,800 5,800 14,950 Virginia 6 779,200 61,803 221,114 West Virginia 41 1,434,800 608,878 1,035,862 Wyoming 1 250,000 50,000 800,000

The total production of coal in the United States in 1873 was as follows:

 STATES AND TERRITORIES. Sq. miles of coal. Tons. Pennsylvania 12,774 34,523,560 Maryland 550 2,674,100 Virginia 185 60,000 West Virginia 16,000 1,000,000 Ohio 10,000 3,944,340 Eastern Kentucky 8,983 50,000 Western Kentucky 3,888 350,000 Tennessee 5,100 400,000 Alabama 5,330 60,000 Michigan 6,700 50,000 Indiana 6,450 1,500,000 Illinois 36,800 3,500,000 Iowa 18,000 350,000 Missouri 23,100 1,000,000 Kansas 17,000 50,000 Colorado, Wyoming, Utah, &c.—lignite . . . . 500,000 Pacific coast—lignite . . . . 500,000 Total . . . . . . 50,512,000

The area of the New Brunswick coal field is very large, but there is only one thin coal bed, too small to work. Nova Scotia produced 411,541 tons of coal in 1873, and Cape Breton island 639,926. The coal is all bituminous and of a fair quality for gas and steam purposes. There is also an unproductive anthracite coal field in Rhode Island and Massachusetts.—The foregoing fields comprise all the carboniferous coal in North America, and it is not probable that any other districts of any extent containing true coal will hereafter be discovered. Near Richmond, Va., is a very deep coal basin of the triassic age, which was the first worked in the eastern states, and after a long suspension work has lately been resumed. There are two other similar small basins in North Carolina, on Deep and Dan rivers, but neither of them is wrought.—Besides the foregoing carboniferous and triassic coal fields, there is in the N. W. part of this continent a very large area of coal fields which should be described with some detail. The coal or the combustible matter of these western basins is of the kind generally called lignite, of an inferior quality and of a more recent age, the tertiary. It has however the same appearance, and is by its chemical composition true coal; and its distribution in extensive basins along the eastern base of the Rocky mountains, bordering immense treeless plains where no other combustible of any kind can be found, gives to these coal fields an immense value. Indeed, in regard to the population of the gold-mining countries of the Rocky mountains, and to the building of railroads across the plains from the Missouri to the Pacific, the lignitic basin of the west is for the future as important as are for the present the Appalachian coal beds or the coal fields east of the Mississippi river. Along the Missouri river and west of it, the true carboniferous formations sink and disappear under the Permian. The line of the 96th parallel of longitude, from the point where it enters the state of Iowa to the southern limits of Kansas, shows nearly exactly the limits of the old coal fields. Further west the Permian, following a gradual westward dip, is overlaid by the cretaceous formations, which reach a thickness of 2,500 ft. or more; and over these, nearer to the mountains, the tertiary measures appear with their numerous and as yet scarcely explored beds of lignitic coal. By the upheaval of the Rocky mountains, the lower tertiary has been thrown up, sometimes to the perpendicular all along the base of the mountains, and there the capacity of some of its beds of coal has been exposed and is already utilized by workings on a comparatively large scale. The whole lignitic basin may be, like the coal fields of the east, subdivided into different basins, not by any positively marked difference in the nature and composition of the lignitic coal or by any difference whatever in the formation of their coal beds, but merely by geographical limitation, as follows: 1. The New Mexico lignitic basin. It is especially of great extent and rich in coal beds along the Rio Grande, on both sides of it, S. of Santa Fé and Albuquerque as far down as Fort Craig, the supply of fuel for the fort being obtained from a bed of lignite 5½ ft. thick, 5 m. E. of Don Pedro. A number of other valuable beds have been reported near San Felipe, and still more abundantly northward, around Santa Fé and up to the Eaton mountains. The coal of Placiere mountain, which is partly anthracite, is 5 to 6 ft. thick. The following section, taken at the foot of the Raton mountains, shows the average distribution of the lignitic formations of this southern basin:

 Ft. in. 1. Sandstone and shale, space covered 60 0 2. Soft shale and clay 35 0 3. Outcrop of lignite showing 2 0 4. Soft shale and fire clay 26 0 5. Outcrop of lignite, thin 1 0 6. Hard gray shale with fossil plants 30 0 7. Hard sandstone in bank 6 0 8. Soapstone shale 2 0 9. Lignite, outcrop, good 2 0 10. Fire clay and shale 36 0 11. Lignite, exposed 2 6 12. Fireclay 6 0 13. Soft shale 30 0 14. Lignite bed opened 4 0 15. Ferruginous and shaly sandstone 50 0

 DISPOSITION OF COAL. Tons. In the manufacture of iron 35,119,709 In steam power in manufactories 27,550,000 Domestic or household consumption 20,054,000 Exported to foreign countries 12,712,222 Used in mines and collieries 9,500,000 In the manufacture of gas 6,560,000 In steam navigation 3,650,000 In glassworks, potteries, and brick and lime kilns 3,450,000 On railways 3,790,000 In chemical works and all other manufactures 3,217,229 In smelting other metals 763,607 In water works 650,000 Total production of Great Britain in 1873 127,016,767

STATISTICS OF THE COAL FIELDS OF GREAT BRITAIN.

NAMES OF COAL FIELDS. Square
miles of
coal.
Thickness of
coal-bearing
strata.
No. of beds
of coal.
Thickness
of coal.
Millions of
tons within
4,000 ft.
Tons of coal
produced
in 1873.

Durham and Northumberland 460  ft.  2,030 ft. 16 ft.  46 ft. 10,037  29,640,397
Cumberland 25 2,000  9 36 405  1,749,036
 Yorkshire ${\displaystyle \scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}}$ Derbyshire and Nottinghamshire Warwickshire Leicestershire
 760 30 15
 4,500 2,950 2,550
 15 5 10
 46 30 45
 18,243 458 839
 15,311,778 ${\displaystyle \scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}}$ 11,568,000
 Lancashire ${\displaystyle \scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}}$ Cheshire
217  6,000  3 62 5,546
 ${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}}$ 17,060,000 1,150,500
Shropshire and Anglesea  9 1,309  8 36 1,570,000
N. Staffordshire 75 5,000 30 150  3,825  3,892,019
S. Staffordshire and Worcestershire  93 1,810  6 65 1,906  9,463,559
North Wales 47 3,000  7 30 2,005  2,450,000
 South Wales ${\displaystyle \scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}}$ Monmouthshire
906  12,000 25 84 32,456
 ${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}}$ 9,841,523 4,500,000
Forest of Dean 34 2,765  8 22 265
 ${\displaystyle \scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}}$ 1,858,740
Bristol 150  5,125 20 71 4,218

Total of England 2,821 80,208  110,055,552
Scotland 9,843  16,857,772
Ireland 156  103,423

Total Great Britain 90,207  127,016,747

—France has a large number of small detached coal basins. The basin of St. Étienne, in the department of Loire in S. E. France, has the largest annual production, about 3,500,000 tons; the basin of Valenciennes in the north, an extension into France of the coal field of Belgium, produces nearly as much, and that near Calais almost 3,000,000 tons. These and three or four others in S. E. France, each yielding about 1,000,000 tons per annum, produce the bulk of the coal of that country. The whole production of France in 1872 was 15,899,005 tons, and in 1873 about 17,500,000 tons. The annual production of anthracite is about 1,000,000 tons. The following tables give the most important statistics in regard to them, derived from the report of a late French parliamentary commission in 1874:

 KINDS. No. of concessions. AREA. PRODUCTION. Square miles. Percent. Tons in1872. Per cent. Bituminous 319 1,527 52 14,459,273 90.94 Anthracite 146 221 24 1,006,525 6.33 Lignite 147 338 24 433,307 2.73 Total 612 2,086 100 15,899,005 100.000

 PROPORTION OFWORKED AND UNWORKED TERRITORY. Square miles. CONCESSIONS. Bitum. Anth. Lignite. Total. Worked 1,434 204 74 57 335 Not worked 652 115 72 90 277 Total 2,086 319 146 147 612

Germany is the largest coal-producing country in continental Europe. In 1872 the coal production of the empire was 42,324,466 tons, of which Prussia proper produced 36,973,411 tons; and there was a considerable increase in 1874. Less than one fourth of the whole product, 9,018,048 tons, is lignite or brown coal. The largest production was in the Rhine provinces, 11,500,000 tons; Silesia, 10,500,000; Westphalia, 10,000,000; and Saxony, 9,500,000. About two thirds (6,139,851 tons) of the brown coal comes from Saxony, where also about 3,000,000 tons of true or carboniferous coal is mined. Belgium is the next in rank as a coal-producing country, having mined 15,658,948 tons in 1872; the two principal districts are those of Liége and Hainaut. Austria mined 10,389,952 tons in 1872, more than half of which (5,676,672 tons) was brown coal. Nearly half of the whole product (5,098,080 tons) came from Bohemia, 1,500,000 from Hungary, and nearly as much from Styria. Nearly all the provinces produce both black and brown coal, or carboniferous coal and lignite. Russia has a large coal area, which like that of Scotland is subcarboniferous, or situated geologically below the formation in which the best coal of England and America is found. The only coal field of Russia belonging to the true coal formation is a small tract in Poland containing 80 sq. m., producing one third of the whole amount mined, which was 1,097,832 tons in 1872. Some good anthracite is reported near the sea of Azov, of which 331,896 tons were produced in 1872. Russia also produced in the same year 27,586 tons of lignite and 738,350 tons of bituminous coal. Spain has a good coal field of the carboniferous age, measuring 3,501 sq. m., but the production was only 570,000 tons in 1872. There is also coal in Portugal, the production in 1872 being 18,000 tons. The coal of New South Wales in Australia is believed to be true coal or carboniferous, not a lignite. The amount mined in 1873 was 942,510 tons, but the product does not increase rapidly, as it was 919,522 tons in 1869. The coal in Italy is lignite or later than the carboniferous age, as is also that of India, covering an area of 2,004 sq. m., and those of China, Japan, New Zealand, and South America, except some true coal in Brazil.

COAL PRODUCTION OF THE GLOBE.

 COAL-PRODUCING COUNTRIES. Sq. miles of coal. Year. Production in tons. United States 192,000 1873 50,512,000 Nova Scotia 18,000 “ 1,051,567 Great Britain 11,900 “ 127,016,747 France 2,086 “ 17,500,000 Belgium 900 1872 15,658,948 Germany 1,800 “ 42,324,466 Austria 1,800 “ 10,389,952 Russia 30,000 “ 1,097,832 Spain 3,501 “ 570,000 Portugal ...... “ 18,000 Australia ...... “ 942,510 India 2,004 “ 500,000 Chili, China, Japan, New Zealand, and all other countries (estimated) ...... .... 1,000,000 Total ...... .... 268,582,022

—The early history and development of coal is very obscure. It appears to have been used by the ancients only to a limited extent. Theophrastus, in his treatise on stones, mentions lithanthrax as used by the smiths of Elis. But the Romans, who excavated several of the ancient aqueducts of France through the coal measures, developing beds of coal, paid no attention to the mineral. The first notice we find in official records of the development of coal in England, the first country in which the mining of coal became a commercial industry, is the receipt of 12 cart loads of “fossil fuel” by the abbey of Peterborough in 850. But evidences exist to prove that coal was used to a very limited extent by the Britons before the Roman invasion; and the discovery of tools and coal cinders near the stations on the Roman wall, indicates that they must have learned its use from the Britons. The first evidence, however, of regular mining operations is found in the books of the bishop of Durham, by whom in 1180 several leases were granted for mining “pit coal,” a term since common among the English miners and writers on coal. The coal of Belgium appears to have been developed about this time, or during the 12th century, near Liége. It is said that a smith named Houillos first used coal in the village of Plenevaux, near that place, about this time, and in commemoration of this discovery the French name of coal is houille. Coal was first used in London in 1240; and in 1300 considerable quantities were made use of. A tax of from 1s. to 10s. per chaldron was imposed on coal in England during 400 years, ending in 1803. The first attempt to make pig iron with pit coal appears to have been in 1612, when a patent for this purpose was granted to Simon Sturtevant, but it was unsuccessful. Dudley also obtained patents in 1619 for the same purpose, but also failed, and was imprisoned for debt in consequence. The first successful effort appears to have been made by Mr. Darby of Coalbrookdale in 1713; and in 1747 cast iron suitable for cannon is said to have been made at this place, both the coal and iron ore used being taken from the same mine. In 1700, 64 furnaces were in blast in the forests of England, producing about 20,000 tons of pig iron annually; in 1788, only 13,000 tons of charcoal iron were made, and 61,300 of pit coal or coke iron; but during 1870, 5,963,515 tons were made with coke and coal. The aggregate steam power of Great Britain in 1860 was 38,635,214 horse power, equal to the productive laboring force of 400,000,000 men, or twice the power of the adult working population of the globe. Nothing more striking or instructive, in regard to the value of coal when utilized by an industrial community, could be stated than this fact.

 Engd. by A. Petersen, Washington, D. C.⁠