on, raises the exchangeable value of raw produce, and raises
also the proportion of raw produce paid to the landlord for rent, it is
obvious that the landlord is doubly benefited by difficulty of
production. First he obtains a greater share, and secondly the commodity
in which he is paid is of greater value.[8]

CHAPTER III.

ON THE RENT OF MINES.

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;