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.