MONEY AND THE MECHANISM OF EXCHANGE 161

some common unit of value, and the provision of some form
of acknowledgment of the residual obligations in question,
will remove this difficulty.
The three points thus raised will be readily admitted,
and can be illustrated with facility. Thus a tailor may
need boots and a bootmaker a coat, but if the tailor can
only find bootmakers who are already sufficiently supplied
with coats and conversely, the exchange cannot be effected.
Then, even if the two whose needs correspond are brought
into relation with each other, the goods to be exchanged
may not be equivalent in value. The coat may, for example,
be worth 10 per cent. more than the boots. It is not sufficient
that the balance be expressed in terms of the coat or the
boots. It is highly inconvenient, to say the least, if it
cannot be made available for the purchase of other goods
by the tailor. If it can receive an expression which makes
it acceptable by other traders, and a satisfactory acknowledgment
 of the bootmaker’s obligation to pay the tailor can be
secured, drawn in such acceptable terms, the hindrance to
zxchange is removed.
The introduction of a general medium of exchange
obviates these difficulties. If, for example, wheat form an
acceptable means of payment to every one, or to a substantial
 majority of the community, the tailor need not
hunt for a bootmaker who needs a coat. Any one who
needs a coat and will give wheat in exchange will provide
him with a means of satisfying his needs, for, with the wheat,
he can obtain the desired boots from any bootmaker who
can suit his fancy. The balance of value, by which the
coat exceeds the boots or the reverse, is both expressed
and paid over without difficulty. If, in place of desiring
a commodity nearly equal in value to a coat, the tailor
requires a dozen articles, each of smaller value, and together
representing an aggregate of value equal to that of the coat,
his desires may be readily gratified; while, if a producer of
such an article as sugar desires a coat, he need not seek for
a tailor who wants a large stock of sugar, since, by gathering
the wheat, which can be secured from the users of sugar in
exchange for the amounts of that commodity which they