David Ricardo (1817)
The metals, like other things, are obtained by labour. Nature, indeed, produces them; but it is the labour of man which extracts them from the bowels of the earth, and prepares them for our service.
Mines, as well as land, generally pay a rent to their owner; and this rent, as well as the rent of land, is the effect, and never the cause of the high value of their produce. If there were abundance of equally fertile mines, which any one might appropriate, they could yield no rent; the value of their produce would depend on the quantity of labour necessary to extract the metal from the mine and bring it to market. But there are mines of various qualities, affording very different results, with equal quantities of labour. The metal produced from the poorest mine that is worked, must at least have an exchangeable value, not only sufficient to procure all the clothes, food, and other necessaries consumed by those employed in working it, and bringing the produce to market, but also to afford the common and ordinary profits to him who advances the stock necessary to carry on the undertaking. The return for capital from the poorest mine paying no rent, would regulate the rent of all the other more productive mines. This mine is supposed to yield the usual profits of stock. All that the other mines produce more than this, will necessarily be paid to the owners for rent. Since this principle is precisely the same as that which we have already laid down respecting land, it will not be necessary further to enlarge on it.
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.
If equal quantities of labour, with equal quantities of fixed capital, could at all times obtain, from that mine which paid no rent, equal quantities of gold, gold would be as nearly an invariable measure of value, as we could in the nature of things possess. The quantity indeed would enlarge with the demand, but its value would be invariable, and it would be eminently well calculated to measure the varying value of all other things. I have already in a former part of this work considered gold as endowed with this uniformity, and in the following chapter I shall continue the supposition. In speaking therefore of varying price, the variation will be always considered as being in the commodity, and never in the medium in which it is estimated.