CHAP. X.

MIDDLE AGES.

273

attention from the earliest ages of which historymakes mention down to the present time, themines of Almaden and of Guadalcanal . Thesemines were well known to the Romans, who ex-pended enormous sums on them: they werecontinued at work by the Moors, and haveonly ceased to be productive within a very fewyears.

The mine of Almaden is of importance to thehistory of the precious metals, though its chiefproduce is quicksilver; but that metal hasbecomeof such indispensable use in the operation of sepa-rating gold and silver from the ores with whichthey are mixed, or from the quartz or other earthsin which they are commonly enclosed, that with-out it the mines both of the new and the oldworld would have been less beneficially and ex-tensively worked than they have hitherto been.

At first the cinnabar or mercury was chieflyused as a paint, but its value for other purposeswas very early discovered. Theophrastus , whowrote 300 years before Christ, mentions-it—aswell as Vertuvius, who was a contemporary ofAugustus; and Pliny , in the following century,expressly speaks of it as the production of Beticain Spain .

The Romans deemed mercury a poison; butnotwithstanding that opinion their matrons usedthe cinnabar as a paint for the face, and the artistsapplied it to their works. Pliny says that the

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