other impurities in the lump, along with pure galena, is then sent to the grinding-mill. This consists either of solid uprights shod with iron, and moved up and down by a horizontal spindle furnished with arms, or a pair of fluted cylinders, through which the ore is made to pass, and it is afterwards ground to the requisite fineness by smooth rollers. The mixed ore, after being ground, is again washed, and the pure galena separated from the impurities. COAL MINES. There are two kinds of furnaces used in the smelting of lead ore-a reverberatory furnace, called a cupola, and the other known by the name of the Scotch fur-bling metalliferous substances; it is discovered in large nace. The first, in the interior, is generally eight feet long, six feet wide, and two feet high at the centre. The fire is placed at one extremity, and is separated from the smelting part by a wall, which is built about half the height of the furnace. The hearth upon which the ore is placed is composed of furnace slags, and it slopes from the wall which separates it from the fire to the other end of the furnace, and is hollowed from the sides to the centre. This is enclosed by an arched roof, in the middle of which is a small aperture for admitting the ore from a hopper placed above it. About 20 cwts. of ore are usually put into the furnace at a time, which is spread equally over the hearth with a rake. For the first two hours, no regular fire is made, a gentle heat merely being kept up by putting small coal on the furnace, the doors of which are kept shut. This is called the roasting process, which is performed principally for the purpose of dispelling all sulphureous vapours from the ore. At the end of two hours the fire is raised, and the metallic lead soon begins to flow from the ore. The smelter and his assistant now stir the ore at intervals, and a shovelful of quicklime is thrown in. This is done in order to liberate the oxide of lead from the ore, and allow it to react upon any sulphuret which may have resisted the roasting. The heat is again increased, and the stirring continued. In about four hours from the commencement, the furnace receives its greatest heat, after which a tap-hole is opened, and the lead runs into an outer basin. From this it is cast in semi-cylindrical moulds, and receives the name of bars. The Scotch furnace is much of the same nature as the above, except that the hearth, sides, and sole plate, are made of cast-iron, from two to three inches thick. The roasting is performed with peat and coke, and the furnace is urged by wooden bellows. In advance of the furnace a basin is placed, for the reception of the lead as it flows from the furnace. The quantity of lead obtained from the mines of Great Britain annually, has been estimated at nearly 40,000 tons. The articles made from lead are sheet-lead, which is cast on large tables, and smoothed and thinned by rollers; lead-pipes, which are generally made by draw ing through a mandril; and leaden shot, which is formed by dropping melted metal in a shower from a great height. Towers for making shot are conspicuous objects in London. Copper. The ores are roasted by a low heat, in a furnace with which flues are connected for collecting the sulphur that is volatilised. The carbonates of copper reduced by fusion, afford a pure copper; and this is an easily wrought metal, useful for many purposes. Copper alloyed with zinc forms brass, which is extensively used for articles of ornament by brassfounders. Tin. The ore of tin, when melted in furnaces and run like iron, is shaped into blocks or pigs. The uses of tin are very numerous, and so well known that they scarcely need to be pointed out. A very important application of tin is in the coating of other metals, such as those of iron and copper, which have been formed into vessels. The silvering of looking-glasses, and the fabrication of a great variety of vessels and utensils for domestic and other uses, are among the advantages derived from this metal. As explained in our article GEOLOGY, coal belongs to the secondary order of rocks, in which it is defined as the carboniferous group. With respect to its origin and character, it is entirely a mass of vegetable matter, which has accumulated in certain situations, and afterwards been covered over and pressed into a hard consistence under other strata-generally mud or sandwhich in time has become layers of limestone or sandstone. Coal is not found in veins or deposits resembasin-shaped patches in different parts of the world, and always in the same position with relation to adjoining strata. Geology being almost unknown as a practical science some years since, frequent trials were made to obtain this fuel where we now know nature never intended that it should be found; although blackish, charred, woody and peaty substances led to the expectation of its presence, and caused the useless expenditure of large sums of money. The coal-seams, together with their alternating strata, are usually called the coal-measures, and the basin-shaped deposits in which these lie are termed the coal-fields. In either form, coal is found in vast abundance in various parts of England, Scotland, and Ireland, and constitutes the most valuable of all our mineral products, for without it most others would be nearly useless. The entire British coal-fields may be classified as follows :— The coal of Scotland.-The coal-fields of Scotland are of great extent and value, indeed sufficient of themselves to furnish the whole empire with an adequate supply of this mineral for a long series of years. Coal is found in several districts of Scotland, as in Dumfriesshire and Roxburghshire, in the more southern counties; but the great field of Scotch coal stretches from south-west to north-east across the centre of the kingdom; and it is to be found in greater or smaller quantities in the counties of Haddington, Edinburgh, and Linlithgow, Stirling, Clackmannan, Kinross, Fife, part of Perth, Ayr, Renfrew, Lanark, Dumbarton, and part of Argyle. Its average breadth is thirty-three miles, and its length upon the mainland of Scotland ninety-eight miles; so that its total area is 3234 square miles. If from this we deduct 360 miles for the space covered by the Frith of Forth, there will remain 2874 square miles of territory, in most parts of which coal is found at different depths and of various qualities, whilst in about 600,000 acres of the same space it may be worked with advantage. The depth of coal varies, but in general it seems to be rather nearer the surface in the western than in the eastern division of the country. There is also a great variety in the number of its seams or strata, as well as in their thickness. The greatest thickness in the island is at Quarrelton, where five contiguous strata are upwards of fifty feet thick. Seams less than eighteen inches are not deemed equivalent to the expense of working them.* The coal of Ireland is found in seventeen counties of that country. The chief district is that of Munster, which occupies a considerable portion of Limerick, and Kerry, and also a part of Cork; next are the Connaught and Leinster districts. Some of the coal-fields are of the carbonaceous, while others are of the bituminous quality. Comparatively little is raised, and almost all the coal used in Dublin, Belfast, and other towns, is imported from England. The coal of England and Wales may be thus classified:-1. The great northern district, including all the coal-fields north of the Trent. 2. The central district, including Leicester, Warwick, Stafford, and Shropshire. 3. The western district, which may be subdivided into north-western, including north Wales; and southwestern, including south Wales, Gloucester, and Somersetshire. Coal is found in these fields in strata of various thickness, alternating with clay, slate, and sandstone, the alternations being frequently and indefinitely repeated. | tinuance of the practice of screening coal at the p These beds or measures commonly repose upon milstone, grit, and shale, which sometimes exceed 120 fathoms in thickness. Under this series is the carboniferous or mountain limestone, varying in thickness up to 900 feet; and this is again succeeded in the descending order by the old red sandstone, ranging from 200 to 2000 feet in thickness. These four different series are generally comprehended in the term coal-formation, although the three last do not form an essential and invariable part of it, being sometimes absent. A general resemblance in their structure is observable in all the English coal-fields, but they greatly differ in minor particulars. By far the most important and best known of all the English coal-fields is undoubtedly that of Northumberland and Durham, the pits of which ship their produce by the rivers Tyne, Wear, and Tees. The coal raised from these mines is of the most valuable character for domestic purposes, and as such has obtained a notoriety throughout the civilised world. There are three principal kinds of coal found in Great Britain:-1. The caking coal (distinguished by various provincial designations), yielding about 40 per cent. of bitumen, the quantity of which is the chief recommendation to a household coal. This is the prevailing kind in the Northumberland and Durham mines. 2. The cannel coal, called in Scotland parrot coal, which occurs in Lancashire, and contains about 20 per cent. of bitumen. 3. The stone coal, known also under many other names, which is the ordinary coal of the Staffordshire and Scotch collieries, and is largely consumed in manufacturing processes. mouth, by which from one-third to one-fourth of t Coal Shafts and Workings. Coal mines are reached by circular shafts, a metal mines; and the sinking of these forms a larg item of expense, for the operation involves the erects and working of a steam-engine to draw off the water. and the blasting of any rocky matter that intervens The working beneath, to form the necessary excava tions, is also liable to great impediments from the o currence of dykes. These are generally of the charme This great northern coal-district commences near ter of dislocations in the strata, a seam of coal being the mouth of the river Coquet on the north, and ex- all at once stopped by a barrier of stone, and contacteu tends nearly to the Tees on the south. As far as at a different level. But although the dykes thas 12 Shields, the sea is the boundary on the east; but from pede operations, they are useful in forming walls t that point it leaves a margin of a few miles between it prevent the intrusion of water. The cutting of a dyke a and the sea, and extends about ten miles west from fault of any extent is carefully avoided by coal-miners, Newcastle. Its greatest length is 58 miles, and its great- as the penetration of this barrier, which nature se est breadth about 24. It supplies a very large portion to have interposed by way of warning to the ardour of of England, including the metropolis, part of Scotland, the excavator, would often admit a rush of waters from and many foreign countries. The coal-measures of this the other side, and cause the inundation of the mi field rest upon the millstone grit and shale, and lie, in for these interruptions assume the office of coffer-das the south Durham portion, under the magnesian lime- in stopping the passage of water in many cases. At stone, the northernmost point of which projects near the Gosfirth colliery, about two miles north of Newcast mouth of the Tyne. In consequence of the basin or boat- the manager described to us, while standing nearly one shaped disposition of the coal, the beds at some places the 90-fathom dyke, that, about the year 1825, a sha appear at or crop out to the surface, while, in the central was attempted to be sunk on what turned out to be the parts of the concave or basin, they lie at great depths. wet side of this great dyke, but it was speedily aban The beds of this series of coal-measures are 82 in num-doned, in consequence of the perpetual influx of wate: ber, and consist of alternations of coal, sandstone, and slate clay, forming an aggregate thickness of 1620 feet. The number of really workable and productive seams of coal in this field are 17; but of these only about four or five yield the best coal. These are variously named as the High Main and the Low Main, the Bensham and the Hutton seams, the last extending over the whole of the eastern part of Durham, and ranging in thickness from 4 to 5 feet, of which, however, 2 feet frequently turn out to be coarse coal, unfit for the market, and suitable only for mending the horse roads. It seems probable that more accurate and complete knowledge will establish the identity of some of those seams which are now distinguished by different names. The extent of the whole surface of this coal-field is a subject of dispute; but, according to the most received approximation, Northumberland contains 243 square miles, and Durham 594 square miles, making 837 square miles for the two counties. Of this the portion already excavated is computed to be about 105 square miles; and from a minute calculation, it has been deduced that, according to the present issue of coal from the chief parts in this field, there remains enough to warm and cheer our posterity for 1700 years to come. It should be mentioned, however, that Professor Buckland, in limited the supply, at the existing rate of conn and waste, to 400 years. This last calculaver, assumed as one of its elements the con The adventurers then merely crossed the dyke by a vancing a few yards; and having thus reached the dry side, they sank the present shaf, in which they wer compelled by this short journey to descend nearly fathoms before they could reach the coal; this, her ever, they succeeded in doing without any obstractas from large quantities of water. Shafts vary in depth, according to the situatia d the stratum or seam to be reached. The deepest art those in the Newcastle district. The writer of the present article descended and inspected twelve d the principal pits in this field, selecting such as win deepest and largest, or otherwise peculiar and in portant. Three of the shafts of these were ead five hundred and odd feet deep, three were each eigh hundred and odd feet, and three others each thousand and odd feet deep. The deepest shaft in the coal-field, and probably in any other, is one thousand six hundred feet deep, and we were about four minutes in descending. This is the celebrated Monkwearmonth shaft, the difficulties encountered in sinking wherb were perhaps as formidable as any upon record. T. is generally believed to be the deepest perpendicular shaft in the world, if the level of the sea is regarded. We find it, however, stated of one near Namur, in the Netherlands, that it is two thousand four hundred feet in depth, although no particulars are given whereby t judge of its relative depth below the level of the sea, of its perpendicularity. The readiest method of forming an idea of the depth of such a shaft as the Monkwearmouth, is to consider that it would contain the Monument of London piled eight times upon itself! In Lancashire, the deepest shafts are about eight hundred feet, and in Yorkshire they are about the same, but seldom more than three or four hundred feet in either district, and in many instances very shallow. The steam-engine is not commonly erected in the collieries of these parts, unless, indeed, on a very small scale, and of a very imperfect kind. The horse-gin and turn-wheel, or roller, are the machines commonly used in these inferior collieries for the purposes of winding or lifting the coal. The horse-gin is the same kind of machine as that usually known by the name, and is generally worked by horses who have seen better days, and indeed now see no days at all, being blind, windgalled, or spavined. The turn-wheel is the least expensive and most dangerous mode of winding. It is, in fact, nothing more than a common well-winch with a flywheel, which is wound by an old woman or boy, on whose equanimity the ascendants or descendants are entirely dependent. The men and boys commonly descend and ascend by inserting one leg into a loop at the end of the pit-rope, and winding the other round the rope, to which also they cling with both arms and hands. Two men commonly go at one end of each of the two ropes, when the loops are used. When the baskets (corves) are employed, three or four, or more, may descend together. Eight persons may descend the Monkwearmouth shaft in a large iron bucket. The number of boys going up and down at one time is sometimes five or six, and they cling to the ropes with as much tenacity as possible, presenting the appearance of a string of onions. The men take the youngest boys on their knees, holding them fast, which, after work, is necessary, for they are sometimes asleep when they arrive at the top. A modern improvement in shaft-machinery is the substitution of iron frames (cages), sliding upon vertical rods or rails, which traverse the shaft perpendicularly; the transit of this plan is easy, steady, and safe. In some collieries it is the practice to descend and ascend by the upcast shaft, which is in fact going down or up a long smothering chimney. We have descended three upcast shafts, each of more than a thousand feet in depth. The celebrated Monkwearmouth shaft is an upcast, and we shall not readily forget our descent of this, during the whole of which we were subjected to the suffocating vapours of the smoke of the flaming furnace at the bottom, and of the vitiated return air. The ropes of this shaft cost £550 per pair, and weigh 5 tons, only lasting, however, about ten months. Many of the ropes in these collieries are flat, and all are of a superior character. The chief danger in ascending is that of being drawn up too high and over the pulleys upon which the ropes run, and which are erected upon wooden frames over the shaft. A bell is rung, by mechanical contrivance, when the men arrive near the surface, but this has sometimes failed; and in the summer of 1842, a pitman was killed by such a failure at a pit in county Durham. The method of excavating the coal from the mines is not always the same in different places, but may, in a general sense, thus be described:-The pit is either level or sloping, according to the seam of the coal, and the process of excavating it furnishes material for sending to the surface up the shafts. A pit may vary from three or four to six feet in height, from the floor upwards; the roof, which is a hardish part of the strata left, being supported by pillars consisting, for the greater part, of unexcavated coal. Sometimes wooden props are used, but these are less safe than the substance of the coal. It may easily be supposed, that great care is required in leaving a sufficiency of these natural props; for cases have been known in which the superincumbent pressure has forced down the roof, and the land on the surface, with houses upon it, has sunk. In excavating, hewers are employed to dig out with picks the masses of coal; and as they proceed in their labours, they cut out evenly-formed apartments, or galleries, all connected with each other, and divided by the rows of pillars which it has been necessary to leave standing. In some instances, the miners must recline or stoop to effect their purpose; and when we remember that they are incommoded with water and foul air, and working in darkness only illuminated by feeble lamps, it must be allowed that their occupations are irksome, and far from being either pleasant or safe. Other persons remove the coal as it is dug, in some cases by means of small wheeled carriages, which they draw, and in others by carrying it in baskets on their back. Being in either way removed to the bottom of the shaft, it is there put in the buckets, or corves, and wound to the surface. Ventilation of Coal Mines. The temperature in coal-pits varies in general from sixty to seventy degrees in deep mines. In one of the Hetton pits, it is sixty-six degrees at the shaft bottom and seventy degrees in the workings. In the deep Monkwearmouth pit, it ranges from seventy-eight to eighty, and even to ninety degrees. The Newcastle coal-pits generate gases more largely than any other. The chief component part of inflammable pit-gases is carbureted hydrogen gas, mixed with unequal quantities of olefiant, carbonic acid, and nitrogen gases. They exhibit a very different degree of inflammability when mixed with atmospheric air, according to the different proportions they contain of nitrogen, carbonic acid, and olefiant gases. The two first gases diminish, the last increases, their inflammability. The most readily explosive mixture of this inflammable compound with common air is one measure of the gas to seven or eight of air. The great objects of ventilation are to dissipate the noxious gases issuing from the coal, frequently at all pores, and to supply the miners with fresh air. Its agent is the difference between the weights of two columns of air, one of which is at the natural temperature, and the other rarefied by the heat of a furnace. (See article VENTILATION). Both by means of doors in the galleries, and the furnaces erected for the purpose, ventilation is carefully attended to, so that a current of fresh air is almost always playing along the passages. In cases where it is presumed that the return or escaping current of air is so impregnated with the inflammable gases of the mine that it would take fire by coming into contact with the flames of the furnace, the air is carried over the furnace through a close brick-work channel (termed a dumb furnace), which opens into the upeast shaft abore the fiery furnace; thus the heat of the fire is made to produce the draught, while the flame does not communicate with the vitiated return air. One of the very highest rates of circulation afforded a result of 59,030 cubic feet of air per minute coursing through the pit, which amount was subdivided into eleven different currents, being an average of 5-366 cubic feet to each current. The ordinary circulation is much below this, but the higher it is raised, the safer and fresher the pit. Notwithstanding all the precautions used, explosions of foul air and accidents will occur. No colliery district, we believe, has been more fertile in explosions of a terrific character than the Newcastle coal-field. At the very lowest calculation, no less than 1500 lives have been sacrificed in or about the collieries of the Tyne and Wear, in little more than the last forty years, and the greater portion of these have been lost by explosions of inflammable gases. Mr Leifchild describes a catastrophe of this nature, the effects of which he witnessed, that occurred in April 1841; and by this calamity thirty-two persons were killed, some of them being fearfully mutilated or scorched to cinders. The acknowledged cause of this explosion, and of many others, was the temporary neglect of the little boy who kept one of the most important doors in the pit. It is supposed that he left this door for a short time to play with another doorkeeper, or trapper, and consequently | cover readily from accidents. The hewers earn, in fair the current of ventilation became deranged. Whenever such a derangement takes place, the contact of a candleflame explodes the pit either wholly or partially, and with more or less havoc. In this instance the pit was shattered to a great extent, but in others it is sometimes not much broken up. In 1839, an explosion occurred in which fifty-one persons were killed; and in 1835, at Wallsend pit, 102 human beings were destroyed by one. Very few persons are unacquainted with the nature of the Davy-lamp, or safety-lamp, invented by Sir Humphrey Davy, and introduced to the miners in 1816. As shown in the adjoining figure, it consists of an oil-lamp enclosed in a wiregauze cylinder, of which the apertures are extremely minute-a square inch of the surface containing 625 openings. Through apertures so small, flame will not pass, and the lamp may therefore be carried into the most explosive atmospheres without risk. Its safety depends upon the cooling agency of the wire-gauze, exerted on the portion of gas burning within the cylinder or lamp. When the fire-damp is to the air in the proportion of 1 to 5, 6, or 7, the cylinder is filled with the flame; but even though the wire-gauze should become red hot, the exterior air is not kindled. It is perhaps possible, by certain chemical arrangements, to force the flame through the gauze, if a strong current times, from 18s. to 20s. per week, or more, and enjoy a cottage and fuel free of payment. The cottages are built in long rows, and form distinct villages. The lads and boys are also well paid, but the putters undergo m many instances very severe labour, which the oldest of them bear well, but it tells visibly upon the youngest The education of the men, women, and boys, is very defective; few can read at all readily, and fewer still e write. They are, in fact, not long emerged from a state of semi-barbarism. Thirty years ago, their Sunday costume was remarkably gay and singular, and their manners equally so. At present, they may be considered to be, when viewed externally, a tolerably well-behaved, shrewd, hard-working, hard-feeding community-not long since, we might have added hard-drinking, but tem perance societies are encouraged by them, and a consider able number of them are Methodists. A special govern ment commission has inquired, during the year 1841, by means of visiting assistant commissioners, into the circumstances of the employment of females (none berg found in the Newcastle pits) and children in coal-mines The results of this commission have occupied a large share of public attention; and Lord Ashley's bill, founded upon them, excludes females altogether from coal-pits, and limits the age of boys employed in the It is very satisfactory to have ascertained that (leadmining excepted) all mines appear to be capable of being worked by men without any serious diminution of their health. The occupation may, by liberal and judicious management, be rendered far from disagree able to those accustomed to it. Surface-works-Consumption of coal. has to be performed; still, they are frequently very extensive, and include steam-engines for drawing the coal, pumping the water, and also departments in which much of the apparatus connected with the pits is made and repaired. From the pits in the Newcastle and Durham districts, railways are laid in communication with the banks of the Tyne; and overhanging the river may be seen many of the terminations of these railways adapted for shooting the coal from the waggons on board the vessels lying ready to receive it. The appe ratus suited for emptying the waggons into the vess is called a staith, and one of these is sketched in the adjoining figure. be employed, but no instance of such an event ever having occurred naturally in a mine is, we believe, recorded; and therefore the Davy-lamp in its original form is es- The surface-works at a coal-mine are less compli teemed perfectly safe, notwithstanding the numerous im-cated than those at the metal-mines, where smelting provements proposed for it. If the miners would always employ this safeguard instead of candles, there can be little doubt that fewer explosions would occur; but the feeble light which it affords renders it unacceptable, and men will actually, and without dispute, frequently risk their lives for the sake of a little more light and the avoidance of a little trouble. Many mines have been conducted since the introduction of this lamp, which, without it, must have been closed, and some have been re-opened that could not be worked in safety with the old steel-mill-a machine of revolving steel and flint, employed before the Davy-lamp in dangerous pits. This is especially the case in what are termed the pillar-workings of the pit, where the ventilation becomes more difficult, and in almost all pillar-workings the Davy, as the pitmen call it, is in requisition. In many pits a locked Davy is delivered to the pitmen, who return it before they leave the pit. A considerable number of lives are lost, singly or in small numbers, by what may be considered as the ordinary casualties of mining, such as the fall of stone from the roof, which is a frequent cause of calamity. In the inferior coal-fields, numerous deaths occur by the breaking of ropes and shaft apparatus, all which are of a much more costly and durable character in the Newcastle collieries. And this leads us to speak of the ascent and descent of these pits. Colliers. The number of men and boys employed above and under ground in the Tyne, Wear, and Tees collieries, or what may be termed the Newcastle coal-field, approximates to 30,000, which may probably be the maximum. To speak more definitely, nearly 13,000 are engaged in the collieries on the Tyne (which are the oldest), 9000 in those on the Wear, the number in those on the Tees being uncertain. The pitmen appear to be a tolerably healthy race of men, of somewhat diminished stature, and of a rather peculiar bodily configuration. Their legs are sometimes bowed, and their backs rather bent, as the results of their constrained position in hewing the coal; while, as a set-off, their muscular lopment is considerable, and, being spare, they re The cost of coal on being raised from the pit is always very much below the selling price to the consumer, a large addition being made by the merchants through whose hands the article passes, in the shape of dues fe freight, carriage, commission, &c. Good coal in Seat land may be had for about 10s. or 11s. per ton; bet in London, the expense of the sea-carried Newcastle wal is enormous; the coal, in general, which originally est 12s. to 14s. per chaldron, being raised to about 50 to the consumer. Speaking of the abuses of the cas trade, Mr M'Culloch, in his " Dictionary of Commeres," makes the following statements:-" Abuses have nuated themselves into most departments of the b ness; and to such an extent have they been carried, that it takes, at this moment, a larger sum to convey a che dron of coal from the pool, a little below London Brigs, to the consumers in the city, than is sufficient to defray CHARGES UP TO THE TIME OF ARRIVAL IN THE PORT of a chaldron of coal into the waggon costs from 11d. to lad.; and admitting that to raise coal from the hold is a little more difficult, still, if 4d. were allowed, it would be a most liberal payment. But the truth is, that this item should be struck off altogether. It is occasioned by a regulation peculiar to the Thames, which prevents the crews of colliers from performing this indispensable part of their peculiar duty. In the outports, to which, luckily, this preposterous regulation does not extend, the crews act as coal-heavers, and they do so without either asking or obtaining additional wages. And there certainly is no reason whatever for supposing that the case would be materially different in the port of London, were it not for the regulation referred to. In 1829, the total amount of money paid to the coal-heavers was L.107,566, 13s.; of which at least L.90,000 may be saved to the citizens by simply allow ing the crew to perform the function of coal-heavers." The consumption of coal in Great Britain, according to a statement made by Mr Taylor, an experienced individual in the coal trade, and laid before a committee of the House of Lords, was as follows: The annual vend of coal carried coastwise from Dur- 08 64 Tons. 3,300,000 Pier duty, lights, &c., paid by Home consumption, say one-fifth, 660.000 Factorage and del credere com 006 001 017 04 42 155 £2 10 7 Since this statement was made, the consumption is believed to have greatly increased, and, including the coal exported to Ireland and to foreign countries, the total quantity raised annually is not less than 23,000,000 of tons, the price paid for which is reckoned to be eight millions sterling a-year. SALT MINES. Deposits of salt are chiefly found amongst secondary rocks; and rock-salt is almost invariably accompanied by clay, sandstone, and gypsum (from which last plaster of Paris is made), either above or below it, sometimes both; and the countries containing salt-deposits are for the most part flat. It is found either in the form of rock-salt, or disseminated in brine springs in many countries; but some, as the capitals of Hindostan, are so destitute of it, that, in the shape of stamped cakes, it once passed as money, according to some authorities. Perhaps the most extensive deposition of rock-salt in the world is found at Wielitska, near Cracow, in Poland. It has been worked as a mine since the year 1251, and its excavations are said to extend more than a league 2 10 7 from east to west; the salt produced being of an irongrey colour, in which are enclosed cubes of a pure white. After being let down by a rope for 230 feet, the visiter is led through galleries perfectly dry, and of considerable height and breadth, until he arrives at two chapels composed entirely of salt, and hewn out of the solid mass. Images, as well as pillars and ornaments of the same material, adorn the place, and reflect the rays of light issuing from the lamps of the guides, producing a beautiful and novel appearance. Descending lower by ladders, the visiter finds himself in an immense hall or cavern of salt cut with great regularity, and many hundred feet in length. A thousand persons might dine in it without inconvenience; and when illuminated by flambeaux, its splendour is not inferior to that of a palace hall. Of these charges, but little reduction need be looked for in those incurred in the rivers Tyne and Wear, and in the rate of freight; and as the government duty of 68 per chaldron has been abolished, the charges that admit of further reduction are the municipal dues, and those attending the delivery of coal to the consumers; and in these, certainly, there is ample room for retrenchment. The most important item, in those forming the charges in the port of London, is the fee of the coalwhipper, or coal-heaver-that is, the deliverer of the coals from the ship to the barge or lighter. This fee is about 1s. 7d., and is at least five times as great as it ought to be. At Newcastle and Sunderland, the filling There are some extensive beds of rock-salt in England; two found in Cheshire are known to extend a mile and a half north-east and south-west, and upwards of three-quarters of a mile in width. The surface of the lower bed is about 220 feet from that of the ground, |