because whoever offers a commodity for sale, desires to obtain a
commodity in exchange for it, and is therefore a buyer by the mere fact
of his being a seller. The sellers and the buyers, for all commodities
taken together, must, by the metaphysical necessity of the case, be an
exact equipoise to each other; and if there be more sellers than buyers
of one thing, there must be more buyers than sellers for another.

This argument is evidently founded on the supposition of a state of
barter; and, on that supposition, it is perfectly incontestable. When
two persons perform an act of barter, each of them is at once a seller
and a buyer. He cannot sell without buying. Unless he chooses to buy
some other person's commodity, he does not sell his own.

If, however, we suppose that money is used, these propositions cease to
be exactly true. It must be admitted that no person desires money for
its own sake, (unless some very rare cases of misers be an exception,)
and that he who sells his commodity, receiving money in exchange, does
so with the intention of buying with that same money some other commodity.
Interchange by means of money is therefore, as has been often observed,
ultimately nothing but barter. But there is this difference--that in the
case of barter, the selling and the buying are simultaneously confounded
in one operation; you sell what you have, and buy what you want, by one
indivisible act, and you cannot do the one without doing the other. Now
the effect of the employment of money, and even the utility of it, is,
that it enables this one act of interchange to be divided into two
separate acts or operations; one of which may be performed now, and the
other a year hence, or whenever it shall be most convenient. Although he
who sells, really sells only to buy, he needs not buy at the same moment
when he sells; and he does not therefore necessarily add to the
_immediate_ demand for one commodity when he adds to the supply of