4. Those export mantfactures then, the labourers in



FOREIGN TRADE. 16l

which belong to the natural population, are exchanged
for foreign manufactures or foreign luxuries.* Those
export manufactures, which are wrought up by the ex-
crescent population, are exchanged for the agricultural
produce of foreign countries; on which countries, then,
we so far depend for the first necessaries of life, the
means and the materials of human subsistence.
5. This excrescent population will not accumulate in
a country beyond a certain limit. In the first place,
along with every extension of it there must be an in-
creased importation of food, which will therefore have
to be fetched from greater, or more impracticable dis-
tances than before. The sea-coasts, or river-sides of an
exporting country, will only supply a given demand for «
corn;t and should the demand exceed this, the addi-
tional supplies must be drawn from the interior, and
the heavy expense of land- carriage added to the ex-
penses of navigation. It is thus that, with every acces-.
