THE SALT MINES OF EUROPE. The salt-mines of Cheshire, and the brine-pits of Worcestershire, according to the best authority, not only supply salt sufficient for the consumption of nearly the whole of England, but also upward of half a million of tons for exportation. Rock-salt is by no means confined to England, it is found in many countries, especially where strata of more recent date than those of the coal measures abound. Though in some instances the mineral is pure and sparkling in its native state, it is generally dull and dirty, owing to the matter with which it is associated. The ordinary shade is a dull red, from being in contact with marls of that color. But notwithstanding, it possesses many interesting features. When the extensive subterranean halls have been lighted up with innumerable candles, the appearance is most interesting, and the visitor, enchanted with the scene, feels himself richly repaid for the trouble he may have incurred in visiting the excavations. The Cheshire mines are from 50 to 150 yards below the surface. The number of salt-beds is five; the thinnest of them being only about six inches, while the thickest is nearly forty feet. Besides these vast masses, there is a large quantity of salt mixed up with the marl beds that intervene. The method of working the rock-salt is like that adopted for the excavation of coal; but it is much more safe and pleasant to visit these than the other, owing to the roof of the excavations being much more secure, and the absence of all noxious gases, with the exception of carbonic acid gas. In the thinner coal-seams, the roof, or rock lying above the coal, is supported by wooden pillars as the mineral is withdrawn; while, in the thicker seams, pillars of coal are left at intervals to support the superincumbent mass. The latter is the plan adopted in the salt-mines. Large pillars of various dimensions are left to support the roof at irregular intervals; but these bear a small proportion to the mass of mineral excavated. The effect is most picturesque; in the deep gloom of the excavation, the pillars present tangible objects on which the eye can rest, while the intervening spaces stretch away into night. The mineral is loosened from the rock by blasting, and the effect of the explosions, heard from time to time re-echoing through the wide spaces, and from the distant walls of rock, gives a peculiar grandeur and impressiveness to the scene. The great charm, indeed, on the occasion of a visit to these mines, even when they are illuminated by thousands of lights, is chiefly owing to the gloomy and cavernous appearance, the dim endless perspective, broken by the numerous pillars, and the lights half disclosing and half concealing the deep recesses which are formed and terminated by these monstrous and solid projections. The pillars, owing to the great height of the roof, are very massive. For twenty feet of rock they are about fifteen feet thick.