e#. We must not say that all water
is useful, but only that such water is useful as we can actually use.

It is now easy to see why things, in order to be wealth, must be
#limited in supply#; for we never want an unlimited quantity of
anything. A man cannot drink more than two or three quarts of water in
the day, nor eat more than a few pounds of food. Thus we can understand
why in South America, where there are great herds of cattle, the best
beef is not wealth, namely, because there is so much that there are not
people enough to eat it. The beef which is eaten there is just as useful
in nourishing people as beef eaten in England, but it is not so valuable
because there is plenty of beef to spare, that is, plenty of beef not
wanted by the people.

#12. What we must aim at.# Now we can see precisely what it is that we
have to learn in political economy. It is #how to supply our various
wants as fully as possible#. To do this we must, first of all, ascertain
what things are wanted. There is no use making things unless, when made,
they are useful, and the quantities of things must be proportioned to
what are wanted. The cabinetmaker must not make a great many tables, and
few chairs; he must make some tables and more chairs. Similarly, every
kind of commodity must be supplied when it is most wanted; and nothing
must be over-supplied, that is manufactured in such large quantities
that it would have been better to spend the labour in manufacturing
other things.

Secondly, we must always try to produce things with the least possible
labour; for labour is painful exertion, and we wish to undergo as little
pain and trouble as we can. Thus, as Professor Hearn, of the University
of Melbourne, well described it, #political economy is the science of
efforts to satisfy wants#; it teaches us how to find the shortest way to
what we wish for. The object which we aim at is #to obtain the most
riches at the cost of the least labour#.

#13. When to consume wealth.# To consume a commodity is to destroy its
utility, as when coal is burnt, or bread eaten, or a jug broken, or a
piano worn out. Things lose their utility in various ways, as when they
go bad, like meat and fish; when the fashion changes, as with ladies'
attire; or when they merely grow old, as in the case of an almanack, or
a directory. Again, houses fall into bad repair; ricks of corn may be
burnt down; ships may founder. In all these cases utility is destroyed,
slowly or q