ANTHRACITE, a black, light, mineral substance, resembling coal. It is also called blind coal, and glance coal. Its specific gravity is about 1400 ; it is slowly combustible, but without flame ; and it contains 06 per cent. of pure carbon: it is, in fact, a mineral charcoal. Naphtha may be considered as one extremity of the mineral carbonaceous substances, and anthracite as the other. Tar, petroleum, bitUmen, asphaltum, and the various kinds of coal, form the intermediate members of the series. Anthracite is now much used as a steam-engine fuel. Sir H. De La Beebe and Dr. Lyon Playfair, who were commissioned lately by the Admiralty to investigate the qua lities of steam-coal for the navy, have pointed out the many useful qualities of Anthracite. [FuEL]. Small quantities of Anthracite are found in the primary strata of most countries, as, for instance, in the old slate of Cornwall, Devon, and Cumberland, where the appear ances led to borings and other works in search of coal. in the south of Ireland anthracite occurs in clay-slate and grauwacke, so thick as to be regularly worked for the purpose of burning the lime of the district ; the most considerable collieries have yielded 25,000 tons annually ; and all the coal of the province of Munster, with the exception of that of the county of Clare, is of the same sort. It is found in many of our coal-mines, but generally in those situations where the coal comes in contact with clay-slate.
Anthracite, as a fuel for locomotives, has met with but little success. In America, where wood is largely used for this purpose, great desire is exhibited to substitute anthracite for wood ; but Professor Johnson communicated a paper to the Franklin Journal in 1817, shew ing many reasons why it had hitherto not been very successful. There is a want of rapid ignition and lively combustion ; the intense local heat tends to destroy the grate-bars, to loosen the rivets, and to blister the iron plates ; the ashes of the anthracite fuse into an un manageable sort of clinker ; the sharp angular particles of coal, projected by the violent draught of the furnace obliquely into the ends of the copper tubes, tend to cut the metal near the fire end. Professor Johnson points out modes which, in his judgment, will obviate these several sources of inconvenience, and render the use of anthracite in locomotives desirable.
In a series of experiments made by Messrs. Fairbairn of Manchester, on 280 bars made of different kinds of iron, it was found that an thracite iron, or iron smelted with anthracite instead of other kinds of coal, is superior to other kinds of iron in strength, though not quite equal to sonic of them in elasticity. The results were communicated in extenso to the British Association in 1810.