This country, which, in 1862, produced 9,400,000 tons of coal, requires at least 16,000,000 for its consumption, and imports the difference from Belgium, England, and Germany. The chief coal-basins are situated in the departments of the Loire, du Nord, Saône-et-Loire, and Gard, which furnish about seven-eighths of the whole production. Austria, whose principal coal mines are situated in Bohemia, produces about 3,500,000 tons. Spain possesses magnificent coal-fields in the Asturias and Santanders, but as yet they have been but little worked.
Besides the coal-basins of the mother country, Britain is richly provided with coals in many of her colonies. In New South Wales and Tasmania, in Labuan and Farther India, in Hindostan and New Zealand, in British Columbia and Honduras, valuable basins or seams of coal have been discovered; and a magnificent coal-field, far surpassing in magnitude those of the British Islands, extends from Newfoundland, by Cape Breton, Prince Edward Island, and Nova Scotia, across a large portion of New Brunswick. Thus far it has been but little worked, in countries but thinly peopled, and covered for the most part with boundless forests; but as from its general proximity to the sea it offers every advantage for mining operations, a brilliant future may safely be predicted for the lands it underlies.
The coal-fields of the United States are of still more ample proportions, as they surpass in extent all the known coal-basins of the world besides. Beyond the Alleghany Mountains we find the magnificent Appalachian Coal-field, traversing eight of the principal States in the American Union, from the northern frontiers of Pennsylvania to Alabama, and covering a space of about sixty-five thousand square miles.
Of scarcely inferior extent are the vast coal-fields of Indiana, Illinois, and Kentucky, which nearly equal in magnitude the whole of England; and another smaller but highly important coal region is situated between the lakes Erie, Huron, and Michigan, not to mention the minor coal-basins scattered here and there from Texas to Missouri, and from New York to Maine.
As yet, the Americans have not derived full benefit from their extraordinary coal deposits; but the possession of so vast an accumulation of power allows us to predict a future of almost boundless enterprise and production for that wonderful country.
While in most of our coal-seams deep shafts have to be sunk to obtain the coal, and steam power has to be constantly employed to prevent its submersion, the Appalachian Coal-field is intersected by three great navigable rivers, the Monongahela, the Alleghany, and the Ohio, all of which lay open on their banks the level seams of coal. At Brownhill, on the first of these rivers, the main seam of bituminous coal, ten feet thick, breaks out in the steep cliff at the water’s edge. Horizontal galleries may be driven everywhere at very slight expense, and so worked as to drain themselves, while the cars laden with coal, and attached to each other, glide down on a railway so as to deliver their burden into barges moored to the river’s bank. The same seam may be followed the whole way to Pittsburg, fifty miles distant. Being nearly horizontal, it crops out, as the river descends, at a continually increasing, but never at an inconvenient, height above the Monongahela. Besides this main seam, another layer of workable coal, six feet thick, breaks out on the slope of the hills at a greater height. Here almost every proprietor can open a coal pit on his own land, and the stratification being very regular, he may calculate with precision the depth at which coal may be won.
One of the most remarkable collieries in the world is that of Maunch Chunk (or the Bear Mountain) in Pennsylvania, where an enormous bed of anthracitic coal, nearly sixty feet thick, and probably caused by the doubling back of a twenty-eight feet seam upon itself, is quarried in the open air; the overlying sandstone, forty feet thick, having been removed bodily from the top of the hill, which, to use the miners’ expression, has been ‘scalped.’
CHAPTER XXXIII.
BITUMINOUS SUBSTANCES.
Formation of Petroleum—Enormous Production of the Pennsylvanian Wells—Asphalte used by the Ancients—Asphalte Pavements—The Pitch Lake of Trinidad—Jet—Its Manufacture in Whitby.
The class of bituminous minerals exhibits a long series of inflammable substances, which are supposed to be derived from the decomposition of organic matter in the rocks containing them. Some (Petroleum—Rock-naphtha) issue in a fluid state from the earth, while others pass by insensible gradations from petroleum into pittasphalte or maltha (viscid bitumen), and the latter as insensibly into the solid form of asphalte. Certain bitumens, again, differ but slightly in composition from bituminous coals, so that it is, in reality, very difficult to draw a decided line between them. Hence it is highly probable that in petroleum we see the product of a primeval vegetation which, under the influence of chemical change and heat, has partly assumed a liquid form, and oozing from the deep-seated strata in which it was confined by terrestrial revolution, now permeates the superficial rocks, or exists collected in subterranean cavities, whence it issues in jets and fountains whenever an outlet is made by boring.