picuously explained, but every word is
as applicable to land as it is to mines; yet he affirms that "it is
otherwise in estates above ground. The proportion, both of their produce
and of their rent, is in proportion to their absolute, and not to their
relative fertility." But suppose that there were no land which did not
afford a rent; then, the amount of rent on the worst land would be in
proportion to the excess of the value of the produce above the
expenditure of capital and the ordinary profits of stock: the same
principle would govern the rent of land of a somewhat better quality, or
more favourably situated, and therefore the rent of this land would
exceed the rent of that inferior to it, by the superior advantages which
it possessed; the same might be said of that of the third quality, and
so on to the very best. Is it not then as certain that it is the
relative fertility of the land which determines the portion of the
produce which shall be paid for the rent of land, as it is that the
relative fertility of mines determines the portion of their produce,
which shall be paid for the rent of mines?

After Adam Smith has declared that there are some mines which can only
be worked by the owners, as they will afford only sufficient to defray
the expense of working, together with the ordinary profits of the
capital employed, we should expect that he would admit that it was these
particular mines which regulated the price of the produce. If the old
mines are insufficient to supply the quantity of coal required, the
price of coal will rise, and will continue rising till the owner of a
new and inferior mine finds that he can obtain the usual profits of
stock by working his mine. If his mine be tolerably fertile, the rise
will not be great before it becomes his interest so to employ his
capital; but if it be less productive, it is evident that the price must
continue to rise till it will afford him the means of paying his
expenses, and obtaining the ordinary profits of stock. It appears, then,
that it is always the least fertile mine which regulates the price of
coal. Adam Smith, however, is of a different opinion: he observes, that
"the most fertile coal mine too regulates the price of coals at all the
other mines in its neighbourhood. Both the proprietor and the undertaker
of the work find, the one that he can get a greater rent, the other,
that he can get a greater profit, by somewhat underselling all their
neighbours. T