s fast with an increase of supply
the monopoly price will be high for it, and it will pay the monopolist
better to restrict the output and sell the limited supply at a high
price, because a large reduction of price will not stimulate a
proportionably large increase of consumption. So where the marginal
utility sinks slowly, it will pay to increase the supply and lower the
price, for each fall of price will stimulate a large increase of
consumption.

Since the marginal utility of a number of increments of supply will
not be the same in the case of any two commodities, it is evident that
the determination of monopoly prices is a very delicate operation.

It is not possible to present even an approximately accurate
classification of commodities in relation to the powers of a Trust or
Monopoly. But the following considerations will assist us to
understand why in some cases a Trust appears to raise prices, in
others to keep them as they were, and in others even to lower them:--

(_a_) The urgency of the need which a commodity satisfies enables the
monopolist to charge high prices. Where a community is dependent for
life upon some single commodity, as the Chinese on rice, the
monopolist is able to obtain a high price for the whole of a supply
which does not exceed what is necessary to keep alive the whole
population. Thus a monopolist of corn or rice in a famine can get an
exorbitant price for a considerable supply. But after the supply is
large enough to enable every one to satisfy the most urgent need for
sustenance, the urgency of the need satisfied by any further supply
falls rapidly, for there is no comparison between the demand of famine
and the demand induced by the pleasures of eating.

A monopoly of a necessity of life is therefore more dangerous than any
other monopoly, because it not merely places the lives of the people
at the mercy of private traders, but because it will generally be the
interest of such monopolists to limit supply to the satisfaction of
the barest necessaries of life.

Next to a necessary in this respect will come what is termed a
"conventional necessary," something which by custom has been firmly
implanted as an integral portion of the standard of comfort. This
differs, of course, in different classes of a community. Boots may now
be regarded as a "conventional necessary" of almost all grades of
English society, and a monopolist could probably raise the price of
boots considerably without