ubstances.

The chief activities of living beings are those relating to the
maintenance of life. In other words, animals must feed, and they must
also protect themselves against extermination. In the case of all other
animals this is a very simple matter, they simply live in immediate
contact with their food, migrating or perishing if the supply gives out.
In the case of mankind the conditions are different and vastly more
elaborate. Savage peoples excepted, man does not live within close touch
of the things he requires; indeed, he cannot, for he depends upon all
the world for what he uses. In a less enlightened state many of these
commodities were luxuries; in a civilized state they have become
necessities. Moreover, nearly everything civilized man employs has been
prepared by processes in which heat is employed.

Therefore one may specify several classes of human activities and
employments:

(_a_) The production of food-stuffs and other commodities by the
cultivation of the soil--_Agriculture_.

(_b_) The preparation of food-stuffs and things used for shelter,
protection, or ornament--_Manufacture_.

(_c_) The production of minerals for the generation of power, such
as coal, or those such as iron, copper, stone, etc., required in
the arts and sciences--_Mining_.

(_d_) The exchange of food stuffs and commodities--_Commerce_.

(_e_) The transfer of commodities--_Transportation_.

It is evident that the prosperity and happiness of a people depend very
largely on the condition of their surroundings--that is, their
environment. If a country or an inhabited area produces all the
food-stuffs and commodities required by its people, the conditions are
very fortunate. A very few nations, notably China and the United States,
have such diverse conditions of climate, topography, and mineral
resources, that they can, if necessary, produce within their national
borders everything needed by their peoples.

The prosecution of such a policy, however, is rarely economical; in the
history of the past it has always resulted in weakness and
disintegration. China is to-day helpless because of a policy of
self-seclusion; and the marvellous growth of Japan began when her trade
was thrown open to the world.

For the greater part the environment of a people is deficient--that is,
the locality of a people does not yield all that is required for the
necessities of life. For instance, the N