THE INSIDE VIEW OF A COAL-FIT, You must observe, presents a very different aspect to those splendid subterranean excavations that lately came under our observation, and which, although nothing: more than the simple workings of the salt mines in Cheshire in England, and at Wieliczka in Poland, ex-! hibited such scenes of subterranean grandeur and brilliancy, when lighted up by the candles fixed to the sides of the rock.* coal formation, one of the largest in the world, extends, with some interruption, from the western foot of the mountains across the Mississippi." It is also to be found in the island of Cape Breton, and has been recently discovered in such abundance on the banks of what was called Hunter's River, in New Holland, that its name has, in consequence, been changed, and is now called Coal River,—a discovery that must be of the utmost consequence to the infant colony of New South Wales, especially as it is said, that plenty of iron ore, and some indications of copper, are also found in the coal district. Coal, in abundance, is also met with, particularly near Macquarrie Harbour in Van Diemen's Land; and, in a letter, dated 14th November 1823,* the celebrated Italian naturalist Brocchi, who was at the time employed by the Pasha of Egypt, in directing various scientific researches in the Levant, mentions, that, upon his return to Cairo, he unexpectedly found himself" under the necessity of proceeding to Mount Lebanon, to assist in opening a coal-mine, which had been discovered there.” • The internal appearance of a coal-pit, is very different indeed. Here no dazzling canopy, hanging resplendent over our heads, forms the roof, no sparkling gems, of almost adamantine lustre, decorate the side walls and partitions,-no light, emanating from the pavement, illumines our path as we advance along these dark and dreary passages, where the surrounding shades are rendered more visible by the faint light emitted from the smothered flame of the lamp of safety, while it sheds its feeble rays over the spot where lies reclined on his dusty bed, the sable workman, prosecuting his labours in silence, and almost shrouded in darkness, or where our eyes are bewildered by But the gloominess of the place where his operations are carried on, and the occasional interruption of his labours by dykes, are not the only troubles the miner has to complain of, for he is sometimes impeded in his progress by water, and, at others, is afraid to proceed by the terrors of the fire-damp. The power of the steam-engine, has, however, been long employed with effect to remedy the inconveniences of the former; and the safety-lamp of Sir Humphry Davy, has now superseded the use of a number of contrivances in order to prevent the danger of the latter. With this more wonderful than Alladin's glimmering lights appearing at different intervals in the distance,or our ears are confused by that unceasing murmur which proceeds from yonder group of dusky-looking spectres, who we behold in earnest conversation, in consequence of an interruption they have met with in their work. The interruption, you will observe, proceeds from one of those slips or dislocations in the strata, from which no coal work of any considerable extent is wholly exempt The first interruption is occasioned by the intervention of a whin-dyke, rising almost in a vertical direction through the horizontal strata, which these men were busy in working before such an obstacle interrupted their progress. This is, what I told you, was distinguished, in the language of the miners, by the appellation of a trouble or fault; and the poor fellows will certainly have trouble enough to get through the whin dyke, as they call it, without more on the other side; but this, in the present instance, appears not to be the only inconvenience and ground of alarm, for there is also indications of a slip, and the burthen of their conversation seems to be, as to where they may find the strata again, upon which they have been working, on the other side of this unwelcome intruder. They now seem satisfied, however, that they have discovered the direction in which they may look for the coal strata beyond the interruption; and, wishing them success, we shall leave them to realize their hopes, after having by patient industry overcome the first obstacle by working their way through the dyke. wonderful lamp, the miner can now prosecute his task with safety, and enter the fire damp, or pestilence that walketh in darkness, undismayed as the labourer who carries on his operations amid the glare of the noonday sun.* There is one very remarkable fact in the history or description of coal districts; viz. that numerous beds or seams of coal occur in the same field, although it In this useful discovery, Sir Humphry Davy has, indeed, become the benefactor of his species, and has rendered his name truly illustrious. In the words of Mr Brande, this discovery "ranks among the most valuable presents which philosophy has conferred upon the arts: it has already been advantageously employed in mines scarcely before accessible, and its use is daily extending."—He describes it, as follows: THE MINER'S SAFETY LAMP "Consists of a common oil-lamp, the flame of which is every where surrounded by wire-gauze, the apertures in which should never exceed one-twentieth of an inch square; the wire of which it is constructed may be from one-fortieth to one-sixtieth of an inch in diameter, and of iron or brass, but the former is preferable. "Sir H. Davy has lately constructed some lamps of twilled iron gauze, containing 16 wires in the warp, and 30 in the weft. This material is nearly as permeable to the light and air as the ordinary gauze, and is much stronger, so that it will resist blows and pressure. "The principle of safety, consists in the cooling power of the wire in regard to flame. If a piece of wire-gauze, sufficiently fine, be held horizontally in the centre of an inflamed jet of carburetted hydrogen gas, it will cut off the upper half of the flame, while the lower half continues to burn; the gas passes through the wire, and the upper half may still be inflamed again in the usual way, after having been so far cooled by the intercepting wire as to be extinguished. So, in the wire cage of the lamp, the gas flame continues to burn, but it cannot make its escape through the wire in an inflamed state, so as to cause an explosion of the external atmosphere." rarely happens that more than two or three are of sufficient thickness to bear the expense of working.* This fact, of so many coal seams or strata being in the same field, with the great thickness of some of them, the main coal in Staffordshire being no less than 30 feet thick, that in the Ashby de la Zouch 13 feet, and many seams in other fields in England and Wales, being from 6 to 9 feet in thickness, with the extensive tracts that these coal districts are found to cover, must give us pretty correct ideas of the abundant diffusion of this valu ́able mineral, rendered more so by its usual accompani ments lime-stone and iron-stone; the former of which would be of comparatively less value without the aid of coal-and the latter, as the abundance of our fur-naces and bloomeries, which are scattered over our extensive coal districts, evidently testify, would be very disadvantageously situated indeed, at a distance from these black depositories. † * In the Newcastle coal pit strata, you must have observed, that there are a number of beds of coal lying one over the other, at different distances, but many of them are very inconsiderable in point of thick*ness. The two most important, are those distinguished by the names of the high and low main-the thickness of the former being 6 feet, and of the latter 6 feet 6 inches. The lowest of the two, you saw, was 120 yards below the other, eight beds intervening between them; while the upper lies from 76 fathoms below the earth's surface, having in its train a number of beds also lying over it at different distances; the highest & thin seam of about eight inches, being at the depth of twenty-two and one-half fathoms below the surface. + Behold then, the wisdom and beneficence of the Deity, in thus joining as it were, and connecting so many different formations; render. ed so essentially valuable by such an union, and so intimately connected are they, that the lime-stone formations of the coal basins, may But the bare mention of this SEMI-METAL, as its name implies, iron-stone,-this uniting link betwixt two classes of minerals, so very different in many of their properties, reminds me, that I am dwelling too long upon this important divison, and that I have still that order, with which it brings me in immediate contact to consider, viz., the ORDER OF METALS. Before turning, however, to that grand division of the mineral kingdom, let us consider a little, some of those important uses, to which the order of inflammables are, or may be applied, so as to contribute to the comforts of our species. But what is this that steps so unseasonably and sullenly forward in the order of combustibles, as if ashamed to be seen moving in their train or associated with them, and yet seems justly placed at the bottom of the list, on account of its deficiency in that property, which renders the others valuable-its difficulty of combustion,-no less being necessary, to make it change its form, than the powerful operation of the blow-pipe, or the concentrated heat which proceeds from the focus of the burning-glass?-It is the diamond! What? the diamond! formerly the king of gemsnow dethroned—and become the very lowest in the or be said to encompass, if not mix with their very contents; and so necessarily are the beds of coal and the strata that contain the other valuable mineral associated, that, a celebrated mineralogist, in speaking of the coal field on the north side of the Forth, seems to identify the necessity of the two being together, by saying: "the coal field, and of course the iron-stone field;" as if it was presumed to be understood, by those who were acquainted with these formations, that where the une was, the other must necessarily be. T |