The veins of silver were situated in a range of pine covered hills of no considerable height, affording quarries of good marble, in contact with which substance the silver was mostly found. These mines were probably opened at a very early period, but the precise date does not appear. The ore, "or silver earth," as the Greeks called it, was extremely hard and probably very pure and rich in the yield of metal, as the Greeks, from their defective knowledge of chemical processes, could not extract the silver with profit when united with Jerge'proportions dJot-herrnetals. Con-traryto common experience, the ore appears to have assumed the form of layers rather than of veins. The mines were worked, either by perpendicular shafts, or by tunnelling the side of the hill. Pillars of the ore, were of course left, or the superincumbent mass was supported by props of timber, which was largely imported for the purpose. The noxious vapors exhaling from the mines were carried off by shafts of ventilation'. The ore was removed partly by simple machines, partly by unassisted labor. On reaching the mouth of the mine they were broken small with iron pestles in store mortars. These pieces were then ground down smaller, washed, strained through sieves, and sorted into qualities ot different richness. In the silver ore of Laurium lead was largely present and according to Pliny, the ore was first melted down to the substance called "Stannum," a union of lead with silver.— This was taken to the refining oven, where the silver was separated by heat and the lead remained half glazed in the form ot litharge, which in its turn was reduced. But the ancients were also familiar with the use of quicksilver, in the extraction of other metals, and the moderns have only a claim to rediscovery in this respect The bellows and charcoal were employed to produce the extreme heat required in refining processes. Various substances are mentioned as the products of tiiese ancient metallic operations; the flower of gold and copper; the foam of silver, with some others, all of which were used in medicine. In the mines of laurium copper, cinnibar, and sil, a lightish yellow earth much used by painters, and containing iron were also found.