Political Econoifiy. 2^5 
The commercial system supposes a benefit is derived 
from a balance of trade ; or an excess of exports over 
imports. 
Agriculture is necessary to subsistence ; the employ- 
ment of the surplus produce is matter of choice : and 
whenever more that is useful can be obtained by means 
of exchange, than can be produced at home, by the same 
labour and capital which is employed in effecting the ex- 
change ; then a portion of the inhabitants may be 
more profitably engaged in foreign commerce than in do- 
mestic employments. And this must always be the case 
so long as a considerable diversity of circumstances exists 
among nations. A country possessing favourable soil 
and climate, valuable productions, and numerous popu- 
lation, with arts highly improved, may dispense with fo- 
reign commerce ; may enjoy more prosperity without it^, 
than other nations may be able to attain with its assist- 
ance : but as no nation can possess every advantage, in 
as great degree as all other nations, a judicious exchange 
of commodities will always be productive of profit ; en- 
riching those individuals whose capitals and services are 
employed, and rendering them instrumental in diffusing 
general prosperity. 
It is stated that foreign commerce, by a diversion of 
capital and labour, withholds the means of domestic im- 
provement. In extensive countries certain portions will 
possess facilities for foreign commerce superior to other 
portions ; and as commercial adventurers seek only the 
best markets, it may often happen that the commercial 
districts purchase supplies abroad, which might be fur- 
nished, perhaps on terms nearly as favourable, by some 
other district at home, which thus loses the benefit of the 
supply. But a limitation of supply to home production 
would be to establish a system of monopoly, which must 
always be considered inequitable, except when granted 
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