The price of all metals, though liable to slow and gradual variations, varies less from year to year than that of almost any other part of the rude produce of land: and the price of the precious metals is even less liable to sudden variations than that of the coarse ones. The durableness of metals is the foundation of this extraordinary steadiness of price. The corn which was brought to market last year will be all, or almost all, consumed, long before the end of this year. But some part of the iron which was brought from the mine two or three hundred years ago, may be still in use, and, perhaps, some part of the gold which was brought from it two or three thousand years ago. The different masses of corn, which, in different years, must supply the consumption of the world, will always be nearly in proportion to the respective produce of those different years. But the proportion between the different masses of iron which may be in use in two different years, will be very little affected by any accidental difference in the produce of the iron mines of those two years; and the proportion between the masses of gold will be still less affected by any such difference in the produce of the gold mines. Though the produce of the greater part of metallic mines, therefore, varies, perhaps, still more from year to year than that of the greater part of corn fields, these variations have not the same effect upon the price of the species of commodities as upon that of the other. _Variations in the Proportion between the respective Values of Gold and Silver._ Before the discovery of the mines of America, the value of fine gold to fine silver was regulated in the different mines of Europe, between the proportions of one to ten and one to twelve; that is, an ounce of fine gold was supposed to be worth from ten to twelve ounces of fine silver. About the middle of the last century, it came to be regulated, between the proportions of one to fourteen and one to fifteen; that is, an ounce of fine gold came to be supposed worth between fourteen and fifteen ounces of fine silver. Gold rose in its nominal value, or in the quantity of silver which was given for it. Both metals sunk in their real value, or in the quantity of labour which they could purchase; but silver sunk more than gold. Though both the gold and silver mines of America exceeded in fertility all those which had ever been known before, the fertility of the silver mines had, it seems, been proportionally still greater than that of the gold ones.