ething around twenty-five millions. The
eastern plains emerge more and more as centres of production.

The increased use of metal and the invention of coins greatly stimulated
trade. Iron which now became quite common, was produced mainly in
Shansi, other metals in South China. But what were the traders to do
with their profits? Even later in China, and almost down to recent
times, it was never possible to hoard large quantities of money.
Normally the money was of copper, and a considerable capital in the form
of copper coin took up a good deal of room and was not easy to conceal.
If anyone had much money, everyone in his village knew it. No one dared
to hoard to any extent for fear of attracting bandits and creating
lasting insecurity. On the other hand the merchants wanted to attain the
standard of living which the nobles, the landowners, used to have. Thus
they began to invest their money in land. This was all the easier for
them since it often happened that one of the lesser nobles or a peasant
fell deeply into debt to a merchant and found himself compelled to give
up his land in payment of the debt.

Soon the merchants took over another function. So long as there had been
many small feudal states, and the feudal lords had created lesser lords
with small fiefs, it had been a simple matter for the taxes to be
collected, in the form of grain, from the peasants through the agents of
the lesser lords. Now that there were only a few great states in
existence, the old system was no longer effectual. This gave the
merchants their opportunity. The rulers of the various states entrusted
the merchants with the collection of taxes, and this had great
advantages for the ruler: he could obtain part of the taxes at once, as
the merchant usually had grain in stock, or was himself a landowner and
could make advances at any time. Through having to pay the taxes to the
merchant, the village population became dependent on him. Thus the
merchants developed into the first administrative officials in the
provinces.

In connection with the growth of business, the cities kept on growing.
It is estimated that at the beginning of the third century, the city of
Lin-chin, near the present Chi-nan in Shantung, had a population of
210,000 persons. Each of its walls had a length of 4,000 metres; thus,
it was even somewhat larger than the famous city of Lo-yang, capital of
China during the Later Han dynasty, in the second century A.D. Several
o