The importance of the metallic ores and other mineral substances, considered as instrumental in the advancement of national prosperity, is obvious to every one. In announcing that a certain country possesses extensive and skilfully worked mines, either of coal, of iron, copper, tin, lead, or other of the numerous ores, we at once proclaim her wealth in terms that all must understand. They are readily perceived to be essential to the prosecution of the various arts and manufactures that flourish in the present age, and to form a fruitful source of wealth to the country in which they happen to abound. The facility, however, with which one nation can procure these from another, owing to the free intercourse and system of exchange subsisting between them, which thus enables a country, barren itself in mineral treasures, to attain a respectable rank among the wealthy nations of the earth, occasions us to assign to the possession of them within our own soil, an importance infinitely less than is due. We are disposed to consider them too much in the light of mere articles of export, and valuable, chiefly as commodities of exchange: or, if we do not bestow too much consequence on their exchangeable value, we at least allow too little to their intrinsic worth. Yet, when we assign to the products of the mineral kingdom their proper rank in the scale of national blessings, they take their place beside that of a fertile soil, or a salubrious climate,--blessings we may still enjoy, though we adopt the exclusive and selfish policy of ancient Egypt, or of modern China. In short, we should value these mineral productions, not as we value one of our great staple commodities, tobacco, on account of its nominal price, but on their own account--not by the gain derived from parting with, but that derived from keeping them. Nor should we confine our solicitude to procuring now, on the easiest terms, the means of supplying our immediate wants; but with a more comprehensive view, look forward and provide for the period, when the growing wants of the unborn millions destined to people our almost boundless territory, will create a demand for these substances, in quantities which either foreign nations, with comparatively exhausted mines, will be unable to supply, or to purchase which, we must appropriate that produce (the produce of a large portion of the surface of the soil,) which should be devoted to the more legitimate purpose of furnishing to its inhabitants the means of subsistence and employment.