It will be sufficient to remark, that the same general rule which regulates the value of raw produce and manufactured commodities, is applicable also to the metals; their value depending not on the rate of profits, nor on the rate of wages, nor on the rent paid for mines, but on the total quantity of labour necessary to obtain the metal, and to bring it to market. Like every other commodity, the value of the metals is subject to variation. Improvements may be made in the implements and machinery used in mining, which may considerably abridge labour; new and more productive mines may be discovered, in which, with the same labour, more metal may be obtained; or the facilities of bringing it to market may be increased. In either of these cases the metals would fall in value, and would therefore exchange for a less quantity of other things. On the other hand, from the increasing difficulty of obtaining the metal, occasioned by the greater depth at which the mine must be worked, and the accumulation of water, or any other contingency, its value, compared with that of other things, might be considerably increased. It has therefore been justly observed, that however honestly the coin of a country may conform to its standard, money made of gold and silver is still liable to fluctuations in value, not only to accidental and temporary, but to permanent and natural variations, in the same manner as other commodities. By the discovery of America and the rich mines in which it abounds, a very great effect was produced on the natural price of the precious metals. This effect is by many supposed not yet to have terminated. It is probable however that all the effects on the value of the metals, resulting from the discovery of America have long ceased, and if any fall has of late years taken place in their value, it is to be attributed to improvements in the mode of working the mines. From whatever cause it may have proceeded, the effect has been so slow and gradual, that little practical inconvenience has been felt from gold and silver being the general medium in which the value of all other things is estimated. Though undoubtedly a variable measure of value, there is probably no commodity subject to fewer variations. This and the other advantages which these metals possess, such as their hardness, their malleability, their divisibility, and many more, have justly secured the preference every where given to them, as a standard for the money of civilized countries.