On the banks of the Nile are several prodigious stone quarries, from which the cities of ancient Egypt were built. Perhaps the largest is that of Haggar Silsibis. Here passages, broad as streets, with walls fifty or sixty feet high, now stretching straight forward, now curved, extend from the east bank of the river into the heart of the mountain, where halls have been hollowed out large enough to contain the Roman Colosseum, the rough hewn irregular roof resting upon immense square or many-sided pillars, some of which are eighty to a hundred feet in circumference. Here numerous blocks, already completely separated from the rock, appear ready to be transported; the labours of the quarry-men having suddenly been arrested by the invasion of the Conqueror, who overthrew the priests of Isis.
One of the most curious quarries of ancient days is found near Syracuse. The greater portion is a hundred feet below the level of the earth, and of vast extent, the whole hewn out of rock as hard as marble, the blocks thus obtained being employed in building Syracuse. It is converted by the monks, who have a convent above it, into a garden—a romantic and beautiful spot, as no wind can touch it. It is filled with a variety of vines and shrubs and fruit trees, among which oranges, citrons, pomegranates, and figs grow luxuriantly, and obtain an unusual size. Sicily produces sulphur in large quantities—the chief sulphur pits being near Girgenti. Most of the inhabitants are employed in them, to the neglect of the rich soil of their island; they labour away in the most primitive manner, pickaxe and spade being the only implements employed.
When a promising vein is struck, the miners set to work, and filling their baskets with the sulphur, carry it out and throw it into large heaps of a conical shape. These mounds are covered over with moist clay, some openings being left for the escape of smoke; the bottom is then ignited, and the matted sulphur flows out through grooves into pans, where it congeals in solid masses. The passages to the mines are so narrow, that persons can with difficulty pass each other; they then expand into high vaults, the roofs of which are ornamented with beautiful crystals of celestine and gypsum. On account of the excessive heat, the workmen labour in a nearly nude state, their dark brown skins sprinkled with light yellow sulphur dust, making them look savage and strange in the extreme. Towards the end of the last century, the sulphur mine of Sommatin caught fire, the conflagration causing the complete abandonment of the pit. For two years it raged, until the mountain, suddenly bursting asunder, a stream of molten sulphur gushed forth, and precipitated itself into the neighbouring river. The mass of sulphur, amounting to upwards of 40,000 tons, was thus obtained by the owners of the former pit, who had believed themselves ruined.
There are sulphur mines in different parts of the world, the largest of which are in Japan, but too remote to be worked with advantage. Gypsum, or sulphate of lime, better known as Plaster of Paris, is found in prodigious quantities at Montmartre, close to that city; but as it can readily be worked without having recourse to subterranean excavation, it need not be mentioned further.
When gypsum assumes an opaque, consistent, and semi-transparent form, it is known as Alabaster. The largest quarries are near Volterra, in Italy. Here the whole population have been employed for centuries, either in cutting it out of the mine, or in converting it into elegant forms of great variety, which are sent to all parts of the world.
Great Britain possesses inexhaustible alabaster mines in the neighbourhood of Derby. Some is worked on the spot, but the finest blocks are sent to the studios of sculptors.
Quicksilver, or mercury, is among the rarest of metals. The only two important mines in Europe are at Almaden, in Spain, and Idria, in Carniola. The former, situated on the Sierra Morena, was for many years farmed off to the Fuggers of Augsburg, but are now worked either by government or private companies. This was one of the most interesting spots visited by the two travellers.
Entering a spacious tunnel, completely walled with solid masonry, they advanced into the very bosom of the mountain. Here galleries branch out in various directions, hewn in the slate forming the matrix of the vein. One of them leads to a vast circular hall, called the Boveda de Santa Clara. At one time a horse gin was employed in this hall for raising the ore, but at present this work is performed through a shaft descending to the lowest level of the mine. Convenient steps lead down from another gallery to the first working level, and thence the descent is by short ladders to deeper storeys. The galleries are of a sufficient height to allow a person to work upright. The upper ones are dry, but the lower are humid and damp, although the water is easily raised by hand-pumps from storey to storey into a large receiver, which is emptied by a steam-engine. So extremely rich are the veins, that although worked for many centuries, the mine has scarcely yet reached a depth of 1140 feet. The present quantity raised annually amounts to eighty-thousand hundredweight of pure mercury. The ore known as cinnabar is of a dark-red colour, and gives a beautiful appearance to the galleries. Sometimes when a hewer detaches a block of ore with his pick mass of quicksilver, the size of a pigeon’s egg, rolls out, and leaping along the floor, divides into thousands of small drops. Owing to the imperfect apparatus with which the ore is sublimated, nearly one-half is lost. Formerly criminals only were employed in these mines. They were conducted at sunrise from prison by a subterranean passage into the mine, and compelled to toil on until the evening, when they were led back again to their dungeons. In a few years the greater number died, through inhaling the poisonous vapours of the mercury. Reduced to despair, a century and a-half ago, they set fire to the galleries, which, being then constructed of wood, were destroyed, and mining operations put a stop to for many years. Only free labourers are now employed, who are not allowed to work longer than six hours a-day. Most of these, however, die between the ages of thirty and forty, and those who exist longer are affected by palsy.
The quicksilver mines of Idria were discovered upwards of three centuries ago by a peasant who had placed a tub under a spring issuing from the mountain side. On attempting to move it, he found it excessively heavy, and on examining the bottom he saw that it was partly full of a heavy liquid, shining like silver. Ignorant of the value of the substance, he had sense enough to take it to a goldsmith, without mentioning the place where he had found it. In course of time, however, a man named Anderlein, having bribed him, became master of the secret, and with several others began to work the mine. In the next century the Venetians drove out the Germans, but were finally compelled by the Emperor Maximilian to give it up, and he restored it to its rightful owners. The mine has since been worked by the State. Ingress to the mine can be obtained by descending a convenient flight of steps, with galleries running off here and there from landing-places, or by descending in a few minutes through a perpendicular shaft in one of the tubs by which the ore is raised. The galleries lead to the various storeys of the mine, the lowest of which is 145 fathoms beneath the surface. The vein itself descends to an unknown depth, and is horizontal, but its extent has not yet been measured. The ores being embedded in limestone of a loose nature, all the galleries had from the first to be supported by wooden props. The wood has, on several occasions caught fire, with disastrous results. Early in this century the labourers observed a thick smoke issuing from the deepest part of the mine. It rose higher and higher, spreading through the upper galleries, yet no fire was to be seen, nor sound of flames heard.
Some of the workmen attempted to reach the scene of the fire, but were driven back by the dense and suffocating smoke, impregnated with vapours. Endeavours were made to smother the fire, but though the mine remained closed for five weeks, no sooner was it re-opened than the fire burst forth more furiously than at first. The howling of the flames ascending from the lowest depths of the pit awed the spectators, and the mercurial and sulphureous fumes arising from it threatened instant destruction to all who might approach. The director of the mine, as a last resource, came to the decision of flooding the works, and a river turned into the shaft ran down it for two days and three nights. At first no perceptible effect was produced, but on the second a terrific explosion shook the mountain as if an earthquake had taken place. The huts near the opening were blown to pieces, and even the stone houses on the slopes of the hill, fell with tremendous crashes. Water, however, gained the victory. Gradually the vapour dispersed, and after a few weeks the workmen were able to descend into the pit. They found, however, the galleries torn up, the vaulted roofs burst, and the stairs destroyed. It took two years to pump out the water, which, it is said, poisoned all the fish in the Idriza.