ne ordinary commodity
for another, as a sack of corn for a side of bacon, or a book for a
telescope, we are said to #barter# them. The operation is also called
#truck# (French, _troc_, barter). Among uncivilised races trade is still
carried on in this way; a traveller going into the interior of South
Africa takes a stock of beads, knives, pieces of iron, looking-glasses,
&c., in order that he may always have something which the natives will
like to receive in exchange for food or services. People still
occasionally barter things in England, or the United States, but this is
seldom done, owing to the trouble which it gives.

If, for instance, I want a telescope, in exchange for a book, I shall
probably have to make many inquiries, and to wait a long time before I
meet with a person who has a telescope to spare, and who is also willing
to take my book in exchange. It is very unlikely that he who has a
telescope will just happen to want that particular book. A second
difficulty is, that the book will probably not be worth just as much as
the telescope, and neither more nor less. He who owns a valuable
telescope cannot cut it up, and sell a part to one and a part to
another; this would destroy its value.

#77. Convenience of Money.# With the aid of money all the difficulties
of barter disappear; for #money consists of some commodity which all
people in the country are willing to receive in exchange, and which can
be divided into quantities of any amount#. Almost any commodity might be
used as money in the absence of a better material. In agricultural
countries corn was so used in former times. Every farmer had a stock of
corn in his own granary, and if he wanted to buy a horse or cart, he
took so many sacks of corn to his neighbour's granary in exchange. Now
suppose that, with corn as money, a farmer wanted to part with a cart
and get a plough instead; he need not inquire until he finds a person
willing to receive a cart, and give a plough in exchange. It is
sufficient if he find one farmer who will receive a cart and give corn,
and any other farmer who will give a plough and receive corn. No
difficulty arises, too, if the cart or plough are not of equal value;
for if the cart be the more valuable, then the farmer finally gets for
it the plough together with enough corn to make up the difference. Money
thus acts as a #medium of exchange#; it is a go-between, or third term,
and it facilitates exchange by dividing the act of