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absorbing importance of mineral or pit coal, the called block-coal; and locally it is very valuable, beword coal alone has come to be used in this cause it can be employed in smelting without being special signification (Ger. steinkohlen, Fr. charbon first coked. It is not very easily kindled, but when de terre).

lighted makes a clear lasting fire. 3. Cherry or Coal is one of the most important of all rocks ; soft coal, which breaks easily into small irregular it consists chiefly of carbon, and is universally cubes, has a beautiful shining lustre, is readily regarded as of vegetable origin. Its geological kindled, and gives out a cheerful flame and heat. relations are noticed in the article CARBONIFEROUS | It is common in Staffordshire. Brown coal or SYSTEM. It occurs in layers or beds, and is always Lignite (q.v.), though for the most part inferior to of a black or blackish-brown colour. Some of the true coal, is nevertheless an inportant fuel in some varieties have a very considerable degree of vitreous countries in default of a better kind. There are, or resinous lustre, while others are destitute of however, large deposits of lignites in some regions, lustre ; some have a shell-like fracture, and others as in North America, which coke well, and which have a highly cross-jointed structure, and are are excellent substitutes for true coal. readily broken into cubical or rhomboidal frag. The use of coal does not seem to have been known ments. The precise characters of coal as a rock to the ancients ; nor is it well known at what time species are not easily defined, and both in Britain it began to be used for fuel. Some say that it was and other countries important cases have occupied used by the ancient Britons; and at all events it courts of law, in which this difficulty was strongly was to some extent an article of household con. felt, as in the great Scottish lawsuit concerning the sumption during the Anglo-Saxon period as early as Torbanehill Mineral or Boghead Coal (q.v.). Coal, 852 A.D. There seems to be reason for thinking indeed, is rather a commercial than a scientific that Britain was the first European country in term, but in a general way we may define it as a which coal was used to any considerable extent. fossil fuel of black colour and stony consistency, | A coal-pit at Preston, Haddington, was granted which, when heated in close vessels, is converted to the monks of New battle between 1210 and 1219. into coke with the escape of volatile liquids and Henry III. is said to have granted a license to dig gases. The variety known as blind coal or anthra.coal in 1234. About the end of the 13th century it cite no doubt gives off scarcely any volatile matter, began to be employed in London, but at first only in but this is because it has undergone a natural dis- the arts and manufactures ; and the innovation was tillation through the action of subterranean heat complained of as injurious to human health. In or of the proximity of intrusive igneous rock. We 1306 the parliament petitioned the king to prohibit may therefore divide coal into two primary divisions the use of coal, and a proclamation was accordingly -Daniely: (1) Anthracite, which does not, and (2) issued against it; but owing to the high price Bituminous coal, which does, flame when kindled. of wood, its use soon became general in London. Anthracite (q.v.) sometimes contains as much as It was for a long time known there as sea-coal, 94, and if we exclude the ash, 98 per cent. of carbon, because imported by sea. and as this element decreases in amount it graduates Several theories as to the mode of the origin of into a bituminous coal. The term anthracite is, coal have been put forth from time to time. The however, still applied to some coals which do not one now generally believed in is that the rank and contain more than 80 per cent. of carbon. Various luxuriant vegetation which prevailed during the synonyms, such as stone coal, glance coal, culm, carboniferous age grew and decayed upon and Welsh coal, are also used to designate this slightly raised above the sea ; that by slow su

subsubstance, which is used chiefly for smelting pur sidence this thick layer of vegetable matter sunk poses and for generating steam. In the United below the water, and became gradually covered States it is also very largely used for domestic with sand, mud, and other mineral sediment; that purposes--heating and cooking. It is difficult to then, by some slight upheaval or gradual silting up kindle, but gives out a high heat in burning Bitu- of the sea bottom, a land surface was once more minous coal includes an almost endless number formed, and covered with a dense mass of plants, of varieties, one of the best marked being cannel which in course of time decayed, sank, and became or parrot coal. Cannel coal is probably so called overlaid with silt and sand as before. At length, from burning with a bright flame like a candle, thick masses of stratified matter would accumulate, and the name parrot coal is given to it in Scots producing great pressure, and this, acting along with

rom the crackling or chattering noise it chemical changes, would gradually mineralise the makes when burned. That of different localities | vegetable layers into coal. Microscopical examina. varies much in appearance, but it is most commonly tion shows that coal consists principally of the corti. dull and earthy, or with only a slight lustre; some cal portions of plants-more especially of the bark of examples are, however, bright and shining. In such trees as Sigillaria-commingled with the debris texture it is nearly always compact, and certain of various other plants, amongst which the spore beds of it admit of being polished in slabs of con. cases and spores of certain lycopodiaceous trees not siderable size, which approach black marble in infrequently occur in great abundance. It seems appearance. Of this material vases, inkstands, probable indeed that many coal-seams simply repreboxes, &c. are made. Cannel coal contains a large sent great swamps and marshy jungles. percentage of ash, but the best cannels are in some As will be seen from the following table places much used for open-grate fires in houses.

peat, lignite or brown coal, and true coal indicate Cannel is for the most part consumed in making by their composition the changes which vegetable gas, of which it yields from 8000 to 15,000 cubic matter undergoes by decay and pressure ; and a feet per ton. When distilled at a low red-heat it

table in which a considerable number of examples yields paraffin oil. The other varieties of bitu. of each substance could be given would show how minous coal are so numerous that, as an Admi. | gradually these substances pass into each other : ralty report states, there are as many as seventy

Wood. Peat. Lignite. Coal. denominations of it imported into London alone.

Carbon ............50.0

60.0 65.7 82-6 Still, among these there are three leading kinds Hydrogen.... ...... 6.2 6.5

5-3

5.6 -1. Caking coal, which cakes or fuses into one

Oxygen............45

33-5 29.0 11.8 mass in the fire. It breaks into small uneven

100.0 100.0 100-0 100.0 fragments, and is found largely at Newcastle and some other localities. 2. Splint or hard coal, | In each of these bodies there is usually a small peroccurring plentifully in Scotland, which is hard, centage of nitrogen, which in the above table has and breaks into cuboidal blocks. This is often I not been separated. In passing from wood or peat

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to coal, the proportion of oxygen and hydrogen fettered with legislative regulations. At a very decreases, these substances being given off in the early period, the corporation of the city of London form of marsh-gas and carbonic acid in the process undertook the duty of either weighing or measur. of decay.

ing the coal brought into the port, and by a series On the continent of Europe, productive coal-fields of statutes commencing with 7 Edward VI. chap. occur in Belgium, France, Prussia, Spain, Silesia, 7, the niayor and aldermen of London, and the jus. and in Russia—the only important Russian coal: tices of the counties, were empowered to fix the field being that of Donetz, on the north shore of the price of coal to be sold by retail ; and in case of Sea of Azov. Coal is also found in India, China refusal by the parties to sell at the prices fixed, to (where several extensive coal-fields occur, in which enter their wharves, or other places of deposit, and coal has been worked from a very early period), | to cause it to be sold at the prices which they had Japan, and the Malayan Archipelago, in Australia set. In addition to the general supervision which and New Zealand, and in Africa. There is evi. | they thus possessed, and the sums which they were dence of promising coal-deposits in several South empowered to exact for their trouble, the corpora. American countries, but, owing to the great supply tions of London and other towns have exacted, and of wood in their forests, there is little temptation still continue to exact, dues on coal for local purto work them. Considerable importance already poses. These were first imposed in London in attaches, however, to the mines of Chili (q.v.). In 1667, after the great fire, in order to enable the corCanada there are small, though valuable, coal. poration to repair the ravages which it had comfields ; but in the United States enormous fields of mitted ; and they have been since continued as a fossil fuel are found. The entire area of these is fund for civic improvements, though, as M'Culloch about 200,000 sq. m., being 83 times greater than has remarked, no improvement could be equal to the area of the coal-fields of Great Britain. But a reduction in the price of coal. In the reign of although the coal-measures of the States are of William III. a general tax, payable to government, vast extent, and contain many valuable coal-seams was laid on all sea-borne coal-a tax which was in

-a few of them 40 and even 50 feet thick at the highest degree unjust to places which were certain places—it has been doubted whether the dependent for their supply on the coasting trade, amount of workable coal in them has not been and oppressive to the whole country, inasmuch as exaggerated. In proportion to the extent of the it amounted to more than 50 per cent. on the price seams, the quantity of coal annually raised in the paid to the owner at the pit's mouth. The tax States is small, and amounted to 160,000,000 short | varied in amount, not only at different periods, tons of 2000 lb. each in 1892. The distribution of reaching its highest point of 98. 4d. per chaldron the coal-fields of Britain and North America is dis. | during the great war, but also in different parts of cussed at CARBONIFEROUS SYSTEM.

the country, being higher in London and the south Coal-supply of Britain.—The probable duration of England, and lower in Ireland and Wales, whilst of the British" coal-supply is a question which Scotland for a considerable period was altogether until recent years rarely excited any public exempt. The tax itself, with all its inequalities, anxiety. Early in the 19th century attention was abolished in 1830; and the tax on coal, had been called to the subject by Sir John Jong collected for local purposes in London, was Sinclair, Mr Robert Bald, and Dr Buckland, but abolished in 1889. The repeal, in 1845, of the the existing store of coal was generally believed duty on coal exported to foreign countries was to be practically inexhaustible-its exbaustion at a measure of much more doubtful policy. The all events seemed to be relegated to so remote a annual quantity of coal exported from Great Britain date as to relieve the nation from all anxiety on during the years from 1890 to 1898 was from 25,000,000 the matter. In recent years, however, Professor to 38,000,000 tons. For the regulation and inHull, from a more accurate survey of British coal spection of mines, explosions, &c., see MINING; fields than was possible before the map of the where also mention is made of the varying arrangeGeological Survey had been published, came to the ments as to the proprietorship of mines. The conconclusion in 1860, that at the then rate of produc dition of colliers and salters in Britain is discussed tion we had enough coal to last for 1000 years. at SLAVERY. For coal-tar products, see COALBut as the rate of consumption was yearly increas. TAR, DYEING. See also the articles FUEL, GAS ing. it was obvions that our coal-supply might not AND GASES, PETROLEUM. last nearly so long. In 100 years, as Professor Coal-whipping is the name given to a mode of Jevons showed, if the same rate of increase con. | unloading coal from vessels at anchor to barges, tinued, the annual consumption would be 415,000,000 which convey them to the wharves. When the tons, and our coal-fields by that time would be mumber of these men at work on the Thames was nearly exhausted. A Royal Commission was about 2000, public-house keepers got into the baliit appointed in 1866 to consider the whole question, of acting as middlemen; the trade fell into such a and came to the conclusion in 1871 that at the then state, that the men were virtually slaves to the rate of consumption there was enough coal to last publicans. They asked for the interference of the for 1273 years, but with a constantly increasing legislature. An act was passed in 1843, and a consumption this term would necessarily be re- Coal-whippers' Board was formed, which contracted duced. The amount of coal at all depths down to for the whipping of ships of coal, and employed the 4000 feet was estimated at the date of the Royal men; and other acts were passed in 1846 and Commissioners' Report to be 90,207 million tons, 1851. But in 1856 the coal-owners agreed with the while including the coals at greater depths, the total Board of Trade to maintain a Whipping Office, to was 146,480 millions of tons. Although, therefore, give the men a refuge from the publicans, but with. we know approximately the extent of available coal, ont interfering with the liberty of coal-shippers. we cannot tell how long that coal will last, for we The necessity for coal-whippers has been much cannot say whether the present rate of consumption lessened by the use of hydraulic or steam machinery will be maintained, increased, or diminished in the in discharging. future. It seems most probable, however, that the rate of increase of coal used per head of the popula.

See Green and Miall, Coal: History and Uses (1878); tion will follow a diminishing ratio, and that it will

Galloway, History of Coal-mining in Great Britain (1882);

Hull, Coal-fields of Great Britain (1880); Pameley, The be 300 or 400 years before the coal-supplies of these

Colliery Manager's Handbook (1891); Meldola, Coal and islands begin to fail.

what we get from it (1891); H. W. Hughes, A Text-book Coal-trade.- The production and sale of coal, like of Coal-mining (1892); D. M. D. Stuart, Coal Dust an every other important branch of industry, was long | Explosive Agent (1894).

COALBROOKDALE

COALING STATIONS

311

Coalbrookdale is a district in Shropshire, 1970, from Bombay 1637, and from Ceylon 2130. extending 8 miles along the river Severn ; its coal | Aden is not only an important coaling station in field supplies coal and iron as well as limestone, peace-time for ships using the Suez Canal, but, in and manufactures iron. The village of Coalbrook the event of war with any of the Mediterranean dale, which gives it name, is il miles SE. of powers, it would be the only place in possession of Shrewsbury.

Britain from which a fleet could prevent foreign

ships of war, that had passed through the canal Coal-fish (Gadus carbonarius), a species of

into the Red Sea, from gaining access to the Indian cod, with black upper parts, common in northern

Ocean. The Royal Commission urge strongly that seas. It occurs froin 80° N. lat. to the Mediter. |

Aden should be made secure against the attack of ranean, and is common off North American and British coasts. In Scotland it is often called Saith.

| a small naval squadron.

Bombay is much more than a mere coaling It often measures 2 to 3 feet in length, and may be considerably larger ; occurs in great shoals ; is

| station. It is the greatest port of India, and one

of the busiest entrepôts of commerce in the world. exceedingly voracious. Though decidedly coarse, its flesh is much eaten in northern parts. The

The harbour, defended by batteries and by two

armoured vessels, was declared by Sir Frederick young ones are often caught by boys fishing off

Richards, when naval commander-in-chief on the the rocks, and are variously known as podleys,

East India station, to be sufficiently secured against sillocks, cuddies, and coalseys. See Cod.

any probable attack, Coaling Stations. The question of coaling Kurrachee is a post of immense importance as stations has of late engaged a large share of public the base for the military defence of the north-west attention in Britain. The necessity for maintain: | frontier of India. As compared with Bombay, ing a sufficient number of fortified outposts on the Kurrachee is nearer to England by two days' great lines of British trade has been recognised by steaming. By skilful engineering, the entrance to successive governments, and the work of defence the port, the anchorage, and the wharfage have has, after a regrettable delay, at length been been adapted to the requirements of steamships of vigorously taken in hand. The inquiry by a Royal | large tonnage. The defences, both by batteries and Commission resulted in the publication in 1881-82 torpedoes, are well advanced. of an exhaustive report, from which the present The distance from Ceylon to the Cape of Good article has been compiled.

Hope is 4400 miles, from Mauritius 2100, from The Commissioners estimated the value of British Aden 2130, from Bombay 960, from Singapore 1510, ships and the freights which they carried annually and from King George's Sound 3400. If measures at £900,000,000, British property to the value of are taken to prevent an enemy's ships from coaling £14,000,000 being at all times afloat, the greater in the adjacent seas, Ceylon will be comparatively part on distant voyages. Broadly, the foreign safe from heavy attacks. The possibility of attack trade of the United Kingdom may be divided into by a hostile cruiser must, however, be admitted. two great divisions—the trade with the Americas, The Commissioners carefully weighed the relative and that with the Mediterranean, the East, and | advantages of Galle, Colombo, and Trincomalee. Australia, by the Suez Canal and the Cape. It is Galle, for many years the port of call for mail. chiefly with the latter that we are here concerned. steamers, has gradually been abandoned in favour

On the great trade-route by the Suez Canal to of Colombo. The latter port has a commodious India and to Australia, steamships have entirely harbour, already sufficiently advanced to afford superseded sailing.ships. It is along this route well-sheltered anchorage during the south-west that the possession of a continuous chain of coal. | monsoon. For local reasons, no less than for im. ing stations gives Britain an advantage which it perial considerations, the Royal Commission held is imperatively necessary to maintain. The Cape it necessary that Colombo should be adequately route, again, is essential to the retention by Great protected, both by floating defences and by batteries Britain of her possessions in India, Ceylon, Mauri on shore. Trincomalee is the safest and most comtius, Singapore, China, and Australia. It is by modious harbour in the Indian Ocean, and very this route that reinforcements of troops and neces. capable of defence. But it is out of the course of sary supplies could, in the contingency of war, be trade, and has no facilities for the repair of ships ; despatched to the East with the least exposure to so the Commissioners did not recommend a large capture.

expenditure on fortifications at Trincomalee It must be accepted as a leading principle that Singapore is the next important position in the the defence of harbours should be secured by forts possession of Great Britain. The annual value of and not by ships. The Royal Navy is not main the imports and exports of the Straits Settlements tained for the purpose of affording direct local (of which it is by far the most important) is about protection to seaports and barbours, but for the £100,000,000. At Singapore the quantity of coal purpose of blockading the ports of an enemy, of supplied to passing steamers varies from 15,000 destroying his trade, attacking his possessions, to 20,000 tons a month. Extensive wharves, three dealing with his ships at sea, and preventing an graving-docks, and all the appliances for repairing attack in force upon any special place. It is by ships have been provided by private enterprise. the efficient performance of these duties that | The colonial government has carried out a scheme of British commerce and colonies will be best protected. defenco, planned by otficers of the Royal Engineers.

The great fortresses of Gibraltar and Malta are | The torpedo defences are complete. maintained wholly from resources provided by Hong-kong is the chief centre of British trade with the iniperial exchequer. Improvements in their China, and the only dependency from which that defences have been going forward ever since they trade can be defended. The entries of shipping in came into the possession of Britain ; and it may be 1890-95 included about 30,000 vessels and junks anassumed that Gibraltar and Malta are well pre-nually, of over 7,000,000 tons, and manned by 500,000 pared to resist attack. For the manning of the hands. Graving-docks exist in the hands of comworks strong garrisons of 6000 men are permanently mercial companies, capable of receiving ironclads maintained.

of the largest class which will be seen in the China Pursuing our way throngh the Suez Canal, Sea. The defence of the harbour is now being which, in consequence of recent political changes, made good at the cost of the local and imperial has practically passed under British control, we governments. A small ironclad is stationed at find at Arlen another commanding position. The Hong kong for the defence of the harbour. distance from Suez is 1300 miles, from Mauritius! To the Cape of Good Hope, the distance from

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