Humboldt on the Precious Metals.—In a tract upon thefluctuations in the production of gold, recently put forth byM. Von Humboldt, the following facts are given:—“Welearn from the acute researches of Boekh, how, on the openingof the East by the Persian wars, and by the expedition of thegreat Macedonian to India, gold gradualy accumulated inEuropean Greece, so that in the time of Demosthenes, forexample, the precious metals had sunk to a fifth of the valuewhich they had in the days of Solon. The stream then ranfrom east to west, and so copious was the influx of gold, thatits relative value to silver, which in the time of Herodotus,was as 13 to 1, was at the death of Alexander, only as 10 to 1.The less universal were the communications of trade in theancient world, the greater and more sudden must have beenthe alterations in the relative value of gold and silver. Thus,in consequence of local accumulations of the precious metals,we find that in Rome, just after the conquest of Syracuse,gold was to silver as 17 1-7 to 1; whereas, under JuliusCæsar, its relative value was, for some time, but as 8 1-¾ to 1.The less the quantity of the precious metals actually existingin a country, the more easily can a sudden influx of themoccasion these excessive variations of their value. Thecivilized world is at present assured of stability in the valueof the precious metals, by the extent and rapidity of thecommerce which establishes their equilibrium, and by thegreat quantities of gold and silver already collected. Afterthe revolution in Spanish America, the annual production ofthe precious metals fell, for some years, to one-third of itsformer amount, yet the oscillations of their relative value,during that period, were slight, and hardly ascribable to thedecreased production.” The writer further states that themass of the precious metals brought to Europe from thediscovery of America till the outbreak of the Mexicanrevolution, was 10,400,000 Castilian marks of gold, (worthabout three hundred millions sterling,) and 533,700,000 marksof silver; together worth 5,940 millions of piastres. The silvertaken from the American mines in the above-mentionedperiod would be, when refined, sufficient to form a ball, orsolid globe, of pure silver, eighty-nine feet in diameter. Theproduce of the Russian gold mines in 1837 was valued at800,000£. In the United States, the production of goldincreased, from 1824 to 1834—from the value of 5,000 to thatof 898,000 dollars; since that time it has considerably declined.The gold was found chiefly in North Carolina and Georgia.The amount of the precious metals drawn from the mines ofSiberia and of the United States are inconsiderable in com-parison with that from the mines of Mexico and Peru; yetthey are sufficient to disprove the supposition formerly enter-tained, that large deposits were confined to tropical countries.