Byoie II. MINKS, QUARK IKS, TITS, &c. (>'2S 



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

 in various parts of the 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 

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

 but of peculiar 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 ail 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 coal, and Welsh culm, or stone coal, which burn 

 to ashes without flaming. 



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

 ceous or slaty, and limestone commonly 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. 



8857. The discovery of coal is made by boring, and that operation is generally performed in coal districts 

 as a guide for sinking new shafts. Bv 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 of the 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 coa'ls are scarce, have at one time or other been reported 

 bv ignorant coal-finders to contain coal. How many times, for instance, have our grandmothers, and nurses, 

 repeating their stories, told us, that plenty of coal's might be dug at such and such a place, if government 

 had not prohibited their being dug, for encouraging the nursery for seamen, &c. ? Farey's enquiries, and 

 those of Smith, have brought to light hundreds of instances, where borings and sinkings for coals have 

 been undertaken on advice in situations in the southern and eastern parts of England; attended with 

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

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



3858. The coalfields of Britain will be found scientifically described in Outlines of Geology, by Conybeare 

 and Philips, and also in Bakeu-eWs Geology. 



3859. Limestone, chalk, and building or other stone, are found in strata either 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 earth 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 matters, when worked from the surface, are said to 

 be worked from a pit, 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 greatest advantage. 



3861 The working of quarries is a simple operation, and one depending more on strength than skill. 

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

 the wedge the hammer, and the pinch or lever; recourse being seldom had to the more violent and 

 irregular e'rtects of gunpowder. 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. 



386° 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 ot earth tor carting 

 up the c6al 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 1 he 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, fewer coals are necessary in consequence of the 

 great decree of reverberation which is created, above that which takes place in kilns lormed in the shape 

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

 small 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 ^^/W 1 * 

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

 lime. 'rom the bottom of the kiln within, in some cases, a small building called a horse is raised Iw JUm 

 form of a wedge, and so constructed as to accel, rate the operation of drawing out the burned me»tone, 

 bv forcing it to fall into the apertures which have been mentione I above. 1 n other k to of this kind, in 

 place of this building there is an iron gate near the bottom, which comes c ose to the inside wall ex^rtat 

 the apertures where the lime is uraw,. cut. When the kiln is to he filled, a parcel oltuize or faggots 

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

 pieces, about the s.ste of a man's fist;, and so on alternately, ending with a layer oi coals, which is some 



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