About the middle of the seventeenth century (1654), we find the "Port of Sunderland by the Sea" mentioned, as beginning to be of importance; since that period, its commercial prosperity has gone on increasing, and it has long shared with Newcastle the advantages of the coal trade. It may be mentioned that the highest price ever obtained in the market, is for the best coal from the Wear. In 1800, the quantity of coals sent from the port of Sunderland, including the coastwise and foreign transit, was 303,459 chaldrons: in 1828, it had reached 532,508, the whole exportation during the 28 years having been something short of 12,000,000 chaldrons. About the time last mentioned, there were nine or ten large collieries on the Wear, in connection with which, capital to the amount of £600,000 to £700,000 is stated to have been sunk about 700 colliers were employed; and in 1807, 7,518 ships, together of 102,454 tonnage, cleared with coals from the port of Sunderland. Coals raised from the Wear collieries, as well as from those upon the Tyne, are put into waggons at the pits' mouth, from whence they are conveyed, sometimes a distance of ten miles, to the staithes or spouts, and are either put directly into ships from the staiths, or placed in tubs to be conveyed thereto, or in bulk, in keels, to be cast on board by manual labour. And, as the Custom-house and other dues are collected upon the Newcastle chaldron, a Commission issued, 1 Geo. IV., for "the admeasuring and marking all and every the keels, pan-keels, and pan-boats and other boats, and wains and carts, used or in any time thereafter to be used for the carriage of coals for the port of Newcastleupon-Tyne, and Sunderland upon the river Wear, STOCKTON ON TEES. 329 Cullercoates, Seaton Sluice, Blythnook, and all other places within the counties of Northumberland and Durham, and all and every the members, havens, rivers, creeks, and places whatsoever to the counties aforesaid belonging." Not only has the port of Sunderland for many years shared with Newcastle the advantages and regulations of the northern coal trade, but Stockton, also, since about 1820, has established a sort of rivalry in this important traffic. The great coal owners on the Tyne and Wear appear to make common cause, especially in agreements as to the vend, &c. from which those on the Tees are excluded, apparently as being unwelcome interlopers in the field of business. There are about twelve collieries, which send their produce mostly by rail-roads-in one instance for the distance of twenty-five miles to the Tees, the water of which, however, not being sufficiently deep at Stockton to allow of the lading of large ships, the trade to London is less pushed (in 1830 it was upwards of 1,200 Newcastle chaldrons), than it is to the outports-vessels of 200 tons readily running up the smaller rivers. Some of the coal is of excellent quality, little inferior to the better sorts of the Tyne or Wear, especially the Old Etherley Wallsend: it is, however, tender, and therefore cannot be sent to market so large as some of the prime sorts whose name it bears, and which in this, as in some other cases, is arbitrarily affixed, because, as a Stockton coal merchant explained before the Committee of the House of Commons, the London purchasers "hardly consider they are coals unless they bear that name." CHAPTER XVII. VARIETIES OF COAL. Composition of Coal-Gradations of Fossil Character -Mineral Arrangement-Brown Coal-Black Coal-Glance Coal-Sub-species of each kind— Varieties in the Trade-Difficult to identify several sorts-Qualities of Coal-English, Welsh, and Scotch Coals-Evolution of unconsumed matters during combustion-Burning of Smoke-Stone Coal. IN the earlier Chapters of this Volume, we have entered somewhat at length into the natural history, fossil relations, and geological position of coal; having subsequently described the operations connected with raising it from the mine, we now come to notice those varieties which have been described by Mineralogists, and also to advert to the different qualities of this important fuel recognised in the market, as well as by the general consumer. "It has been customary," says Dr. Mac Culloch, "to regard coal as a combination of carbon and bitumen; but as the latter is itself composed of carbon and hydrogen, it is more accordant to nature, to regard coal as a bitumen, varying in its proportion of carbon, from the fattest SPECIFIC DIFFERENCES. 331 Newcastle coal to the driest blind coal that burns without flame or smoke." If this composition be assumed, we have, as congeners of the different kinds of coal, at the lowest or descending extremity of an imaginary scale, and in contact with anthracite, the non-combustible plumbago or graphite, or, as it is commonly called, black-lead; and at the upper, or ascending extremity, cannel coal, jet, and black amber, approximating to those highly inflammable substances, common bitumen, asphaltum, and the fluids naphtha and petroleum. Another form of arrangement—and one, perhaps, neither less natural, nor less in accordance with the matter of the foregoing pages, would result from the construction of a scale, representative of the different changes ligneous substance undergoes in its transmutation from a recent vegetable state to its ultimate change, by a process of mineralising causes, into perfect coal : something like this has been attempted in previous chapters on the natural history of coal. Jameson, in his arrangement of minerals, "according to the Natural History method," distributes the coal genus into three species, viz. Brown Coal, Black Coal, and Glance Coal: these are again divided into sub-species. I. Brown Coal. 1. Bituminous wood, or fibrous brown coal: the fracture is woody, of a dark brown colour; it burns with a clear flame and bituminous smell. This is the fossil found at Bovey, as already noticed it likewise occurs, differing somewhat in condition, in many other parts of Europe. 2. Earthcoal, or earthy brown coal, which occurs massive, of a brownish or pitch black: it sometimes passes into bituminous wood, with which it is found, and from which it differs principally in its state of aggregation, being commonly of a loose consistency. 3. Alumearth, which flames when exposed to heat. It is said to occur in vast beds in alluvial land it has also been remarked, that where beds of brown coal have a covering of clay, they afford good fuel; but, when the cover is sand, the subjacent coal is alumearth. It is not found in this country, nor much used for fuel. 4. Common, or conchoidal brown coal, which is found at Bovey; it burns with a weak bluecoloured flame, and emits a smell like that of burning bituminous wood. It is distinguished by a high degree of lustre, and conchoidal fracture: we find in it iron-pyrites, honeystone, amber, and a substance resembling retinite. 5. Moor coal, or trapezoidal brown coal: it is the most frangible species of coal; its fragments approaching to cubical. It is not found in this country-though elsewhere it is the most abundant kind of brown coal. II. Black Coal. 1. Slate coal. To this species is commonly referred the rich caking coal of Newcastle, and of the other reputed coal districts. Mr. Hutton, however, considers the slate coal of the Tyne collieries, to consist of the true caking coal of the district arranged in thin alternate layers, with the cannel, parrot, or splint coal, and deriving from this arrangement, its slaty structure. Slate coal is described by Jameson, as being in colour intermediate between velvet-black and a dark greyish-black. Sometimes it presents a pavonine or peacock-tail colouring*, sometimes a columbine tarnish. It oc * Splendid specimens of iridescent coal occur in the anthracite of Pennsylvania: sometimes the pieces are of a deep rich blue; generally, however, the colours resemble those with which our own coals are frequently tinged; but the conchoidal fracture and lustrous appearance of the pieces combine |