less, it will be withdrawn from it.

It is not then by an alteration in the real price of corn that its
production is encouraged, but by an alteration in its market price. It
is not "because a greater quantity of capital and labour must be
employed to produce it," Mr. Malthus's just definition of real price,
that more capital and labour are attracted to the land, but because the
market price rises above this its real price, and, notwithstanding the
increased charge, makes the cultivation of land the more profitable
employment of capital.

Nothing can be more just than the following observations of Mr. Malthus,
on Adam Smith's standard of value. "Adam Smith was evidently led into
this train of argument, from his habit of considering _labour as the
standard measure of value_, and corn as the measure of labour. But that
corn is a very inaccurate measure of labour, the history of our own
country will amply demonstrate; where labour, compared with corn, will
be found to have experienced very great and striking variations, not
only from year to year, but from century to century; and for ten,
twenty, and thirty years together. _And that neither labour nor any
other commodity can be an accurate measure of real value in exchange_,
is now considered as one of the most incontrovertible doctrines of
political economy; and, indeed, follows from the very definition of
value in exchange."

If neither corn nor labour are accurate measures of real value in
exchange, which they clearly are not, what other commodity
is?--certainly none. If then the expression real price of commodities,
have any meaning, it must be that which Mr. Malthus has stated, in the
Essay on Rent--it must be measured by the proportionate quantity of
capital and labour necessary to produce them.

In Mr. Malthus's "Inquiry into the Nature of Rent," he says, "that,
independently of irregularities in the currency of a country, and other
temporary and accidental circumstances, the cause of the high
comparative money price of corn, is its high comparative real price, _or
the greater quantity of capital and labour which must be employed to
produce it_."[60]

This, I apprehend, is the correct account of all permanent variations in
price, whether of corn or of any other commodity. A commodity can only
permanently rise in price, either because a greater quantity of capital
and labour must be employed to produce it, or because money has fallen
in value; and on the contra