This impulse has already been felt as the consequence of recent discovery. The New York papers have just announced the discovery of new deposits of gold in Virginia, “equal to the richest in California;” in Queen Charlotte’s Island gold is said to have been found in great abundance; in New Caledonia and New Zealand it is spoken of; and the research after the precious metal is at the present moment propagating itself throughout the civilised world. And that the activity thus awakened is likely to be rewarded by many new discoveries, and by larger returns in old localities, will appear certain, when we consider, _first_, that the geological position and history of gold-producing regions is far better understood now than it ever was before; _second_, that the value of quartz veins, previously under-estimated, has been established by the Californian explorations, and must lead in other countries to new researches and new trials; _thirdly_, that the increased supply of quicksilver which California promises may call into new life hosts of deserted mines in Southern America and elsewhere; and, _lastly_, that improved methods of extraction, which the progress of chemical science is daily supplying, are rendering profitable the poorer mines which in past days it was found necessary to abandon. About the end of the seventeenth century the reduction in the price of quicksilver, consequent on the supplies drawn from the mines of Idria, greatly aided the mines of Mexico, (Jacob, ii. p. 153;) and of the effects of better methods Rose gives the following illustrations, in his description of the celebrated Schlangenberg mine in Siberia:— “At first, ores containing only four solotniks of silver were considered unfit for smelting, and were employed in the mines for filling up the waste. These have long already been taken out, and replaced by poorer ores, which in their turn will probably by-and-by be replaced by still poorer.”—“The ancient inhabitants washed out the gold from the ochre of these mines, as is evident from the heaps of refuse which remain on the banks of the river Smejewka. This refuse has been found rich enough in gold to pay for washing and extracting anew.”[26] The history of all mining districts, and of all smelting and refining processes,[27] present us with similar facts; and the aspects of applied science, in our day, are rich in their promise of such improvements for the future. If, therefore, to all the considerations we have presented we add those from which writers like M’Culloch[28] had previously anticipated an increased supply of the precious metals—such as the pacification of Southern America, and the application of new energy to the mines of that country, and probably under the direction of a new race—the calmest and coolest of our readers will, we think, coincide with us in anticipating from _old_ sources, as well as from _new_, an increased and prolonged production of the precious metals.