ORDER II.—ANTHRACINEA.
Bituminous Mineral Coal, M. Common Coal. Brown Coal . Black Coal . Cherry Coal. SplintCoal. Cannel Coal. Jet. Lignite. Braunkohle . Pechkoble. Blatterkohle. Bituminoses Iiolz.Houille , Jayet, H.
545. Presents no regular form or structure.
H.=l—2-5. G.=l-2—1-5. Lustre more or less resinous. Streakand Color black, or brown; often grayish, when impure. Opaque.Fracture conchoidal—uneven. Brittle, or sectile.
This species comprehends several varieties.
Pitch, or caking coal, when heated, at first breaks into numerous small pieces,■which, on raising the heat, unite in a solid mass. Its color is velvet-black, or gray-ish-black. Specific gravity 1-269. It takes fire readily, and burns with a lively yel-low flame, but requires frequent stirring to prevent its caking, which prevents theingress of air for combustion. The principal beds at Newcastle afford this kind ofcoal. It comains, according to Thomson, (abstracting the earthy matter,) Carbon24'75, Hydrogen 1375, Nitrogen 5 '25, and Oxygen T5.
Cherry coal has much the appearance of caking coal, but is devoid of the propertyof softening and caking, when heated. It is very frangible, and hence in mining it,there is considerable waste. Near Birmingham , the ioss in mining, including thepillars, amounts to two thirds of the whole. G.=Y265. It burns more rapidly thancaking coal, with a clear yellow flame. The combustible part contains, according toThomson, Carbon 25 5, fiydrogen 4’25, Nitrogen 3 5, Oxygen 1. It leaves about10 per cent, of ashes. It occurs at the Glasgow coal beds, and received its namefrom its lustre and beauty.
The splint coal from the same region, is much harder than the cherry coal, and ishence sometimes called hard, coal. It contains, besides 9 5 per cent, of earthy matter,Carbon 21, Hydrogen 1*5, Nitrogen 1*5, Oxygen 3 5.
Cannel coal has a dark grayish black or brownish-black color, a large conchoidalfracture, and receives a good polish. It takes fire readily, and burns without melt-ing, with a clear yellow flame. On this account it has been used as a substitute forcandles, and hence received its name. This coal contains, on an average, about IIper cent, of earthy matter. The combustible part, according to Thomson, consistsof Carbon 8 25, Hydrogen 2 75, Nitrogen 1'75. It abounds at Lesmahago, aboirttwenty miles from Glasgow , also in different parts of Ayrshire, where it is made intoinkstands, snuff-boxes, and other similar articles. Jel is a variety of cannel coal, butis blacker, and has a more brilliant lustre. It occurs in detached pieces in clay,on tire coast near Whitby , in Yorkshire , and at Ballard Point, and elsewhere. It isthe Gagates of Dioscorides and Pliny , a name derived from the river Gagas, inSyria , near the mouth of which it was found.
Wood coal, or lignite, occurs in the newest formations, and has all the structureand appearance of carbonized wood.