ave been sufficiently
explained, by saying that the energy stored up in a given accumulation
of food reappears when employed in one way, in the efficiency of a
permanent machine; and is, when employed in the other, so far as human
purposes are concerned, as completely lost as it would have been had it
never existed. But if we reconsider a fact which was dwelt upon in our
last chapter, we shall see that the difference is really much greater
than this.

When the potential energy residing in so much food has been converted
into the energy of so much human labour, and when this is so directed
that a productive machine results from it, there is in the machine, as
Dr. Crozier puts it, an indefinitely larger amount of "pure economic
power," than that which has been expended in the work of the labourers'
muscles. While the energy of the labourers has merely resulted in a
bottle, or a cage, we may say, of sufficient strength, the genius of the
man who directed them has captured and imprisoned an elemental slave in
it, who, so long as the cage confines him, will supplement the efforts
of human muscle with his own. But when the energy latent in food is
converted into such efforts as dancing, the result produced is the
equivalent of the human effort only. Thus in the modern world of
scientific enterprise and invention, to invest capital in machinery and
then live on the interest from it, means to press into the service of
mankind an indefinite number of non-human auxiliaries, and year by year
to live on a part of the products which these deathless captives are
never tired of producing.

To spend capital as income on securing immediate pleasures means either
to forgo the chance of adding any new auxiliaries to those that we
possess already, or else to let those who are at our service already,
one after one, escape us--or, in other words, to make the productive
force now at the disposal of any prosperous modern country decline
towards that zero of efficiency from which industrial progress starts,
and which marks off helpless savagery from the first beginnings of
civilisation.

It is no doubt inconceivable, in the case of any modern nation, that a
climax of the kind just indicated could never reach its completion. If
all the capitalists, for example, of Great Britain or America, were
suddenly determined to live on their capital itself, they could do so
only by continuing for a considerable time to employ a great deal of it
precise