nternational values may always be
constructed if we assume a relation of moral law to physical geography;
as, for instance, that it is right to cheat or rob across a river,
though not across a road; or across a sea, though not across a river,
&c.;--again, a system of such values may be constructed by assuming
similar relations of taxation to physical geography; as, for instance,
that an article should be taxed in crossing a river, but not in crossing
a road; or in being carried fifty miles, but not in being carried five,
&c.; such positions are indeed not easily maintained when once put in
logical form; but _one_ law of international value is maintainable in
any form: namely, that the farther your neighbour lives from you, and
the less he understands you, _the more you are bound to be true in your
dealings with him_; because your power over him is greater in proportion
to his ignorance, and his remedy more difficult in proportion to his
distance.[45]

98. I have just said the breadth of sea increases the cost of exchange.
Now note that exchange, or commerce, _in itself_, is always costly; the
sum of the value of the goods being diminished by the cost of their
conveyance, and by the maintenance of the persons employed in it; so
that it is only when there is advantage to both producers (in getting
the one thing for the other) greater than the loss in conveyance, that
the exchange is expedient. And it can only be justly conducted when the
porters kept by the producers (commonly called merchants) expect _mere_
pay, and not profit.[46] For in just commerce there are but three
parties--the two persons or societies exchanging, and the agent or
agents of exchange; the value of the things to be exchanged is known by
both the exchangers, and each receives equal value, neither gaining nor
losing (for whatever one gains the other loses). The intermediate agent
is paid a known per-centage by both, partly for labour in conveyance,
partly for care, knowledge, and risk; every attempt at concealment of
the amount of the pay indicates either effort on the part of the agent
to obtain unjust profit, or effort on the part of the exchangers to
refuse him just pay. But for the most part it is the first, namely, the
effort on the part of the merchant to obtain larger profit (so-called)
by buying cheap and selling dear. Some part, indeed, of this larger gain
is deserved, and might be openly demanded, because it is the reward of
the merchant's k