Kingdom.]
Class L—MINING- AND MINERAL PRODUCTS.
181
the first the cannel is a remarkable variety, the coarserkinds of it being called in Scotland “ parrot,” and some-times splint coal. It contains from 40 to nearly 60 percent, of volatile matter, and the proportion of carbonvaries within the same limits. It burns readily, takingfire like a candle, and giving a bright light, and muchsmoke. The ash varies from about 4 to 10 per cent.This coal yields on destructive distillation a very largequantity of gas, and is profitably used for that purpose.The gas is not only large in quantity, but remarkablypure, and of excellent quality for purposes of illumina-tion. There is a large quantity of this kind of coal inthe Scotch coal-fields, and it has also been found in theNewcastle district, in the Wigan portion of the Lanca-shire coal-field, and in the Yorkshire and Derbyshire coal-fields. America yields cannel coal in Kentucky ,Indiana, Illinois, and Missouri . Cannel coal passes intojet, and may like jet be worked into various ornaments;but it is brittle, and not very hard. The seams aregenerally rather thin, although there are several im-portant exceptions in which the quantity is very con-siderable. The coal of Belgium from one basin (that ofMons ) seems to be of this kind.
Another and far more abundant kind of bituminouscoal is that obtained abundantly in Northumberland and Durham, and commonly used in London and every-where on the east and south coast of England. Thiskind is also highly bituminous, burns with much flame,and takes fire readily, but it swells and alters its formwhile burning, often assuming a striking and verypeculiar appearance, illustrated by a column of coke ex-hibited by Mr. Cory, and also by other cokes shown bythe coal trade of Northumberland and Durham . Thiscaking coal, as it is called, yields, on an average of severalanalyses, about 57 per cent, of carbon, about 37 "6 volatilematter, and 5 per cent. ash. Its specific gravity is 1*257,but sometimes higher. It leaves a red ash in an open fire,but requires to be deprived of its volatile matter beforebeing exposed to a strong blast, owing to its tendency tocement together in a solid mass, and prevent a freedraft through the grate or furnace in which it is em-ployed. Not only the coals of the Newcastle coal-fieldin England, but those of France and Belgium generally, ofBohemia, and Silesia, in Europe, and of Ohio, in NorthAmerica , are of the caking bituminous kind.
The coal of Staffordshire, Yorkshire and Derbyshire ,Lancashire, North Wales , and many other districts, con-tains nearly or quite as much bituminous and volatilematter as that of Newcastle , but does not cake and swellin the fire, and may, therefore, be employed directly wherestrong heat is required without previous coking. The cokeobtained from this coal is little altered in appearance.The coal burns freely, will flame and give much heat,but is generally considered somewhat inferior for house-hold purposes to that of Newcastle , It yields 50 to GOper cent, carbon, 35 to 45 volatile matter, and a smallquantity, often less than 5 per cent., of ash. The ash isoften white. Most of the coals from the inland countiesreadily show white lines on the edges of the beds, owingto the pressure of argillaceous earth which effloresces. Inthis respect they are less adapted for general use than theNewcastle coal, but many of them are of excellent quality.
Next in order to the coals of the midland countiesgenerally, are those of some parts of North Wales , andmany districts in South Wales , which contain a largerper centage of carbon, very little volatile matter andbitumen, and often but little ash; which burn, however,freely and without smoke, and are well adapted forsteam purposes and the manufacture of iron, or where astrong blast and great heat is required. Such coalsexist not only in England, but in France, Saxony , andBelgium to some extent. They are often tender orpowdery, dirty-looking, and of comparatively loose tex-ture, but they often stand exposure to the weather withoutalteration or injury. They are called steam coals, andthe inferior kinds are known as culm. They containcarbon 81 to 85, volatile matter 11 to 15, ash 3, orthereabouts. Several varieties well known in commerceare exhibited by different proprietors, and the respective
analyses will be found in many cases in the body of theCatalogue.
The last kind of coal is that called “ anthracite,” and itconsists almost exclusively of carbon. This coal is alsocalled non-bituminous, as the steam coal is semi-bitumi-nous. The anthracites contain from 80 to upwards of95 per cent, carbon, with a little ash, and sometimes acertain small per centage of volatile matter. They areheavier than common coal, take fire with difficulty, butgive an intense heat when in full combustion with astrong draught. Anthracite occurs abundantly in thewestern part of South Wales, in the south of Ireland , inFrance, Saxony, Russia, and in North America , and theuse of them is greatly on the increase. Amongst otherthings it is used for hop and malt drying, and lime burn-ing with great advantage, but its chief use is in themanufacture of iron. The appearance is often bright,with a shining irregular fracture; the coal is often hard,but some varieties are tender and readily fractured. Theash of anthracitic coal is generally white. As a generalrule the anthracites are deficient in hydrogen, but con-tain a certain proportion of oxygen gas.
The following table represents the weight of waterevaporated by one pound each of several principalvarieties of coal, and is, therefore,—other things being thesame—a good index of the relative value of these fuels;—
Common Scotch bituminous coal
Lbs.
5
Oz.
14
Hastings Hartley main, NewcastleCarr’s West Hartley, Newcastle .
6
14-2
. 7
5
. 7
15*
Merthyr bituminous coal (SouthWales ).
. 8
0
Llangenech steam coal, South Wales ,Cameron’s steam coal, South Wales ,
. 8
14*
. 9
71
Pure Welsh anthracite, South Wales ,
. 10
H
The relative importance of mineral fuel in variouscountries, as indicated by the actual coal area and thereal production of different districts, may be understoodby a reference to the subjoined table. This and otherstatistical facts are based chiefly upon the authority ofMr. Taylor,* but have before been given in their presentform by the author of the present essay. +
Countries.
Coal Areain SquareMiles.
Proportionof wholeArea of theCountrv.
AnnualProductionin Tons.
12,000
1-10
32,000,000
2,000
1-100
4,150,000
520
1-22
5,000,000
4,000
1-52
550.000
Prussia ....
1,200
1-90
3,500,000
Bohemia ....
1,000
1-20
113,000
1-20
4,000,000
18,000
2-9
It will thus be seen how extremely important the coal-fields of the British islands really are when comparedwith any others elsewhere. This is the case not merelyin the total annual production and the proportionateextent of the deposit, but also in the great number ofpoints at which the cojil can be advantageously worked.This will be best seen by reference to the table appended.
The beds with which the coal is generally associated inthe British islands are various sands and shales (imperfectslaty beds) of different degrees of hardness; but theactual coal seams themselves often repose directly onclay of peculiar fineness, well adapted for fire-brick, andgenerally called under-clay. The under-clay is used inmany coal districts for various purposes of pottery.Bands of ironstone (impure argillaceous carbonate ofiron) are very abundant in certain coal districts, but arealmost absent in others. The Scotch coal-fields nearGlasgow, the South Welsh, Yorkshire , and some others,are rich in ironstone, which is the chief source of the vastquantities of iron manufactured in this kingdom.