Almaden, Or Almaden Del Azogue (The Mine Of Quicksilver), a town of Spain, in the province of Ciudad Real, about 50 m. N. of Cordova; pop. about 9,000. It is simply one long street, built on a ridge of quartz rock, which is rich in cinnabar. The quicksilver mines here are perhaps the richest and most ancient in the world. They were wrought by the Romans, who had a town here called Sisa-pona Cetobrix. In the 16th century the Fug-gers of Augsburg rented the mines and worked them for some years. They were subsequently operated by the Spanish government, and until the early part of the present century the laborers were all convicts, but free persons are now employed. The product of the mines is delivered at Seville, and since 1836 has been by contract monopolized by the house of Rothschild. The principal mine is directly under the town, and the great adit is close to the houses, the ascent and descent for the men being by ladders, while the mineral is drawn up a stone shaft by mules. The depth of the workings is about 1,000 feet, and the cinnabar is found in three principal veins several feet thick. The lowest portions of the mine are the richest. Virgin quicksilver is found in pyrites and horn-stein and in a grayish conglomerate, and in some places may be seen running down the face of the rock.

The galleries and permanent works are all splendidly built of stone, and there are extensive storehouses and manufactories of everything needed for carrying on the operations of the mine. The annual yield of quicksilver is from 15,000 to 25,000 quintals, though the proportion of mercury to the ore is only about 10 per cent.; and the mines are apparently inexhaustible. There is a smaller mine near the principal one, and another, called Almadenejos, or Little Almaden, about five miles distant. The number of hands employed is about 4,000. They work day and night during the winter, and in summer the mines are closed, the heat then rendering the mercurial exhalations too dangerous. The miners suffer a great deal from salivation and paralytic affections, but the summer's rest generally restores their health. The government derives an annual profit of about $1,250,000 from the mines. A practical mining school has been established in the town.