Again, during the eighteenth century, the yearly produce of the precious metals—gold and silver together—obtained from the mines of Europe, Africa, and America, is estimated by Mr Jacob (ii. p. 167) at £8,000,000; and for the twenty years previous to 1830, at about £5,000,000 sterling.[23] And although the greatly enlarged produce of the Russian mines, in gold especially, has come in to make up for the failure or stoppage of the American mines since 1800, yet what does the largest of all past yields of gold amount to, compared with the quadrupled or quintupled supply there seems now fair and reasonable grounds for expecting? And what are to be the consequences of the greatly augmented supply of gold which these countries promise? Among the first will be to provoke and stimulate the mining industry of other countries to new activity and new researches; and thus, by a natural reaction, to add additional intensity to the cause of change. Such was the effect of the discovery of America upon mining in Europe, and especially in Germany. “In fourteen years after 1516, not less than twenty-five noble veins were discovered in Joachimsthal in Bohemia, and in sixty years they yielded 1,250,000 marcs of silver.”[24] And, “The discovery of America, and of the mines it contained,” says Mr Jacob, “seems to have kindled a most vehement passion for exploring the bowels of the earth in search of gold in most of the countries of Europe, but in no part of it to so great an extent as in the Bishopric of Salzburg. The inhabitants of that country seemed to think themselves within reach of the Apple of the Hesperides and of the Golden Fleece, and about to find in their streams the Pactolus of antiquity. Between the years 1538 and 1562,[25] more than a thousand leases of mines were taken. The greatest activity prevailed, and one or two large fortunes were made.”—(JACOB, i. p. 250.)