C O A 



703 



COB 



Coal. fore mentioned, we shall state them briefly : The cubi- 

 ^-~~.'~7^' cal and slate coals are chiefly used as fuel in private 

 Ecoaomi- houses, an( j ; n a n manufactories where a strong heat 

 f coal ' 8 re( l u i re d ; the caking coals are most suitable for smith's 

 fires ; when any of these coals are made into coaks, they 

 produce an intense heat in the blast furnace for the ma- 

 king of iron, being used with success in place of char- 

 coal ; the slate coals of the best kinds suit this purpose 

 excellently, as from their strong texture they bear a hea- 

 vy load of iron stone, and a strong blast. 



The coals of South Wales employed in the making of 

 iron, contain less volatile matter than either the English 

 or Scotch coals ; so that in producing a ton of pig iron, 

 only about half the quantity of coals is requisite, as a 

 given quantity contains a great proportion of carbon. 

 That able and practical chemist, Lord Dundonald, 

 whose genius merited a high reward, invented a process 

 by which the volatile parts of the coal were condensed, 

 producing volatile alkali, oil, and tar ; the coals thus 

 distilled were converted into excellent coak, and applied 

 for the purpose of making iron ; this beneficial plan has 

 only been -adopted in a few instances, particularly at 

 Coalbrookdale in England, and at Muirkirk in Scot- 

 land. 



For the production of intense heat and flame in a fur- 

 nace, the slate coals are most' suitable, as, by keeping 

 open, they admit a constant supply of air, which pre- 

 serves a vehement combustion ; on this account they are 

 in great request by the Scotch and Irish distillers. 



Glance coal is used in Ireland as common fuel, and 

 sells at a high price. It is much used for drying grain 

 and malt ; to these it imparts a fair colour ; it it for this 

 latter purpose that the Welsh and Scotch coals, of this 

 kind, are chiefly used. It is also used for the burning 

 of lime, for which it is very suitable. 



Cc-.nnel coal is chiefly used for common fuel : that 

 which is found in Lancashire admits of being turned on 

 the lath, and is made into a variety of utensils and orna- 

 ment?, being susceptible of a very high polish, nearly 

 equal to that of jet ; and of the various coals it is said 

 to be the most suitable for producing the coal gas used 

 for lighting upl arge manufactories. 



Sulphureous coal is but very little used, being so dan- 

 gerous to work; it is only suitable for the burning of 

 Ijme, the making of salt, or forproducing sulphate of iron. 



Culm is used for burning of lime, making of salt, and 

 for steam engines ; it sells at a Tery low price. There is 

 but a small consumpt for this coal in comparison of 

 what is produced annually in the mines. 



Bovey coal is only used as common fuel by the poorer 

 classes of the community, where better fuel cannot be 

 had. 



Ori-in of With respect to the origin of coal, naturalists have in 

 col. general concluded that it ii from the vegetable kingdom, 



particularly from the result yielded by distillation, which 

 11 at follows : 



Watery phlegm. 

 Volatile oil, 

 Volatile alkali, 

 Thick oil, 



which last, on being rectified, produces a transparent 

 thin oil ; but it is remarkable that this oil, by expo- 

 ture to the air, becomes black like animal oils. 



Various theories have been brought forward regarding 

 the formation of coal, and in these much learning and 

 ingenuity have been displayed. From the inconteslible 

 aitd evident trac-.-s of vegetables found so very abundant- 

 ly in the strata of the coal fit-Ids, together with the above 

 analyiis of coal, and the strong light and heat evolved 



in burning, we are inclined to concur in idea with those 

 who conceive it to be of vegetable origin. All the patient 

 investigation of mankind regarding this point of natu- 

 ral history, will never produce an absolute and satisfac- 

 tory conclusion on the subject, there being such insur- 

 mountable difficulties, particularly when we consider 

 that many of the vegetable remains found in the coal 

 strata of Great Britain, belong to classes of plants which 

 are now found only to exist in the equatorial regions ; a 

 fact which favours a theory brought forward by some 

 naturalists, viz. that at the great and universal deluge, the 

 poles of the earth were changed considerably from their 

 position. The formation of our globe, together with the 

 causes which produced the various convulsions and dis- 

 locations which have so evidently taken place in the mi- 

 neral kingdom, must ever remain veiled in a dark impene- 

 trable cloud. We must, however, conclude, that this vast 

 magazine of fuel is most evidently placed by an all- wise 

 Being in the bowels of the earth, in such positions and 

 situations, as are most apt and convenient for the use of 

 man, and where his industry and ingenuity may be ex- 

 ercised. 



Coal being an article so indispensibly requisite for man- 

 kind in civilized society, it is ot great importance to learn 

 every particular regarding its natural history, so that its 

 existence may be traced, by a distinct analogy, in coun- 

 tries widely separated. And when coals are found, it 

 is also very important that the most approved practical 

 and (Economical plans may be applied for working them 

 to the best advantage. The mode of searching and bor- 

 ing for coal ; thfc detail of the most approved plans now 

 used for working the mines ; descriptions of the disloca- 

 tions and obstructions which most frequently occur in 

 -coal fields ; together with the general economy connected 

 with the working of coal mines, will be given under the 

 article MINE. (R. B.) 



COLLIERY, a place where coals are wrought. See 

 MINE. 



COALBROOKDALE. See SHROPSHIRE. 



COAT-OF-ARMS. See ARMS and HERALDRY. 



COBOEA, a genus of plants of the class Pentandria^ 

 and order Monogynia. See BOTANY, p. 171. 



COBALT. See CHEMISTRY Index, and ORYCTO- 

 GNOSY. 



COBBE. See DARFUR. 



COBITES. See ICHTHYOLOGY. 



COBLENTZ, the Conflueniia of the ancients, is a 

 town of France, in the department of the Rhine and Mo- 

 selle, situated at the confluence of these two rivers, from 

 which circumstance its name is derived. Coblentz forms 

 a perfect triangle, one side of which extends along the 

 Moselle, and the other along the Rhine. The streets are 

 in general very regular, and are well paved and lighted, 

 and the houses, which are chiefly of three stories, are buik 

 of stone. The long street of Rheinthor, which traverses 

 the whole town, is reckoned the finest, though it is not 

 uniformly straight. 



There are two collegiate churches at Coblentz, viz. the 

 churches of St Castor and St Florin ; three parish churches, 

 viz. that of the Court, that of Notre Dame, and that 

 of St Castor ; betides the church of St Jjhn, which for- 

 merlv belonged to the Jesuits, and four convents of monks. 

 The collegiate church of St Castor is very old, and the 

 place i.n which it stands was once an island in the Rhine. 

 The large ar.d solid dome is supported by columns of the 

 Corinthian order, which are admired for their lightness. 

 In the choir, which is very beautiful, are four paintings 

 by J. Zick, representing the history of St Goar and tit 

 Castor. Above the choir, and near the principal altar, 



Coal 



