Book II. MINES, QUARRIES, PITS, &c. g^5 



tliis, we may instance coal and limestone: of these minerals, tradition asserts the existence 

 in various parts of tht' island, where from the strata on the surface the modern geologist 

 well knows it is impossible. 



3854. Among the various mineral substances found in quantity in Britain, the chief are 

 coal, lime, building and other stone, gravel, clay, fuller's earth, marl, &c. among the 

 earths ; salt, among saline substances ; and lead, copper, and tin, among the metals. 

 Cobalt, manganese, and some other metals and earths, are found in some places, but in 

 small quantities. No saline or metalliferous bodies ought to be sought for, or attempted 

 to be worked, but with the advice and assistance of an experienced and skilful mineral 

 surveyor; nothing being more common than for proprietors to be induced by local re- 

 ports or traditions to fancy their lands contain coal, lead, or some other valuable subter- 

 raneous product, and to incur great expense in making abortive trials. To ascertain the 

 nature and value of the minerals of an estate of any magnitude, or of one of small size 

 but of pecuhar exterior organisation, it will always be worth while for the proprietor to 

 have a mineral survey, map, and description, made out by a professional man. 



3855. Coal is at present perhaps the most valuable British mineral ; because, among 

 other reasons, it does not appear to be worked in any other country in such quantity as 

 to lessen by importation the home produce. There are three species of coal, the brown, 

 the black, and the uninflammable. To the first belongs the Bovey coal or bitumenised 

 wood, found chiefly at Bovey, near Exeter; to the second the slate coal, which includes 

 the pit and sea-coal, and all the kinds in common use, and also the canal coal, which 

 occurs only occasionally in the coal pits of Newcastle, Ayrshire, and Wigan in Lanca- 

 shire; to the third belong the Kilkenny CQ3I, and^elsh culm, or stone coal, which burn 

 to ashes without flaming. . - ,, . 



3856. The indicathms of coal are different in different coal districts. In general the surface is argilla- 

 ceous or slaty, and limestone comnionly forms an accompanying stratum. In some collieries near New- 

 castle, however, limestone is Wanting; but whinstone, sandstone, and others of secondary formation, are 

 present in a great variety of forms. 



3S57. The discovery of coal is made by boring, and that operation is generally performed in coal districts 

 as a guide for sinking new shafts. By this means the owners procure most essential data on which to 

 proceed, being informed beforehand of the nature of the earth, minerals, and waters, through which they 

 have to pass; and knowing, to an inch or so, how deep the coal lies, as well as the quality and thickness 

 of the stratum bored. It is confessedly of the first importance, either to the inhabitants of a district in 

 general, or to the owners oPthe soil in particular, to be able to detect and work such veins of coal as may 

 exist under their soil; and hence we find, on enquiry in the neighbourhood, that almost every common, 

 moor, heath, or piece of bad land, in parts where coals are scarce, have at one time or other been reported 

 by ignorant coal-finders to contain coal. How many times, for instance, haveoiiir grandmotliers, aiid nurses, 

 repe;iting thciV stories, told us, that plenty of coals might be dug at such and such a ph-.ce, if governmc'tit 

 had not prohibited their being dug, for encouraging the nursery for seanien, &c. P Farey's enquiries, au<J 

 those of Smith, have brought to light- hundreds of instarices, where borings and sinkings for coals have' 

 been undertaken on advice in situations m tl>e southern and eastern parts of P^ingland ;. attend<2d with 

 heavy and sometimes almost ruinous expenses to the parties, though a source of proiit to the pretended 

 coal-finders. These attempts a very slight degree of geological knowledjre would have shown to be vain. 



3858. The coalfields of Britain will belfound scientifically described in Outlines of Geologic ,hy Conybeare 

 z.ndVhi\ii)s, and aho III Jjahetecirs Geology. -'-^ . _ -, 



3859. Limestone, thalk, and hitilding or other stone, are found 111 strata eitlier on or 

 near the surface. At a great depth it is seldom found worth while to work them. 

 When stones of any kind are procured by uncovering the eartlii and then working them 

 out, they are said to be quarried ; but when a pit or shaft is sunk, and the materials are 

 procured by working under ground, they are said to be mined. , 



3860. Gravel, chalk, clay, marl/ and other loose ^naWers, when worked from the surface, are said to 

 be worked from a i)it, and' hence the terms stone, quarry, gravel, clay, or marl pit. Little knowledge of 

 geology is in general required for the discovery of gravel or marl; but, still, even a little would be found 

 of the grcat^t advantage. . 



3861. The^ieorking (if qnnrries is a simple operation, and one dep^iditig more on strength than skill. 

 In quarrying sandstone, consisting of regular layers, the work is performed chiefly by means of the pick, 

 the wedge, thfltjliamn|pr, and the pinch or lever; recourse being seldom had to the more violent and 

 irregular effects of gurtpowder. But for many kinds of limestone, and for greenstone and basalt, blasting 

 with gunpowder is always resorted to ; and some of the rocks called primitive, such as granite, gneiss, and 

 sienite, could scarcely be torn asunder by any other means. 



3862. The burning of lime may be considered as belonging to the subject of quarrying. This operation 

 is performed in what are called draw kilns, or perpetual kilns. These should always be close to or near 

 the quarry, and either situated at a bank, or furnished with a ramp or inclined plane of earth for carting 

 up the coal and lime to the top of the kiln. Lime-kilns may be built either of stone or brick ; but the 

 latter, as being better adapted to stand excessive degrees of heat, is considered preferable. The external 

 form of such kilns is sometimes cylindrical, but more generally square. The inside should be formed in 

 the shape of a hogshead, or of an egg opened a little at both ends and set on the smallest ; being small in 

 circumference at the bottom, gradually wider towards the middle, and then contracting again towards the 

 top. In kilns constructed in this way, it is observed^ewer coals are necessary, in consequence of the 

 great degree of reverberation which is created, above that which takes place in kilns formed in the shape 

 of a sugar-loaf reversed. Near the bottom, in large kilns, two or more apertures are made; these are 

 siTiall at the inside of the kiln, but are sloped wider, both at the sides and the top, as they extend towards 

 the outside of the building. The uses of these apertures are for admitting the air necessary for supplying 

 the fire, and also for permitting the labourers to approach with a drag and shovel to draw out the calcined 

 lime. From the bottom of the kiln within, in some cases, a small building called a horse is raised in the 

 form of a wedge, and so constructed as to accelerate the operation of drawing out the burned limestone, 

 by forcing it to fall into the aiiertures which have been mentioned above. In other kilns of this kind, in 

 place of this building there is an iron gate near the bottom, which comes close to the inside wall, except at , 

 the apertures where the lime is dra%vn out. When the kiln is to be filled, a parcel of furze or faggot*' 

 is laid at the bottom, ever this a layer of coals, then a layer of limestone (which is previously broken inta . 

 lucces, about the size of a man's fist), and so on alternately, ending with a layer of coals, which is some- 



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