Page:Indian Journal of Economics Volume 2.djvu/30

H. STANLEY JEVON$ favorable for the development of certain manufacturing industries. 8. Inv?tm?nt of Capital--Waiting for return.-- From the point of view of economic theory, one essential feature of capital in every form in which it enters into commerce and industry, is that it enables a producer or consumer to wait for the enjoyment of the results of his labor. ? When a machine is constructed the owner the.reof enjoys the fruits of his labor, or of the labor which he has purchased, throughout the number of years through which the machine remains in service. The machine may go out of service, either because it wears out, or because there is no longer a sufficient demand for the products which it is used in making Any great public work is similar in economic pro- perties to a machine, except that generally speaking it cannot be moved and that it takes longer to construct. There is again a further difference, in that most engineeriug structures have a much longer duration of service than any machine, and, with the growth of population, they therefore continue for several decades to increase in earning capacity. Just as a machine must yield from its use income sufficient for a depreciation which will replace the capital machine by the time it is income derived by the fund being accumulated sunk in purchasing the worn out, so fnust the community from the use of any public work be sufficient either to provide a sinking fund for replacing it when annually for repairs a sum worn out sufficient to or to provide keep all ?e parts of the work in a condition equal to new. Such an annual charge for maintenance must be a first charge on the net revenue gained from the work, balance of the income goes to pay the 1 W. S. Jevoas, Theory of Political Marshall, Pr/nc/p/? o! E?mm?, Book 2, olmp. tv, and the interest 4th edition, pp. ?6 ? ?.