Quicksilver, or mercury, is the only metal which remains liquid at ordinary temperatures. It is white and very brilliant, as may be seen in common thermometers. It boils at six hundred and sixty degrees of heat; and freezes, and assumes a crystalline texture, at forty degrees below zero. It is extensively used in its various forms in the arts, and also for medicinal purposes. The thermometer and barometer illustrate some of its uses in its pure state; the backs of our common mirrors are covered with it, which gives them their reflecting power; it is used extensively in separating some of the purer metals from the mixtures with which they are found; and in some of its forms or combinations, it is the basis of calomel, corrosive sublimate, vermilion, &c. Mercury is found in various parts of the world. Among its principal mines are those of Almaden, near Cordova, in Spain, and of Idria, near Carniola, in Austria; though it is also found in Peru, California, Italy and China. Formerly most of the quicksilver came from Germany; but more recently the largest production is probably in Spain. So extensively is it used, that in 1831, over three hundred thousand pounds were brought from the continent into England; and for the fourteen years ending in 1828, the imports of it into Canton, by the English and Americans, averaged nearly six hundred and fifty thousand pounds a year, worth some three hundred and fifty thousand dollars. Of all the quicksilver mines, those of Idria, mentioned above, are some of the most interesting, and demand a particular description, as they have been celebrated in natural history, poetry and romance. The ban of Idria, is a district of Austria, lying west of Carniola. The town, which is small, is seated in a deep valley, amid high mountains, on the river of the same name, and at the bottom of so steep a descent, that its approach is a task of great difficulty, and sometimes of danger.