keeping the
series of engines intact, and what is given to them as pay for their
services cannot accrue to any one as an income from the series of
instruments so maintained. It is the earnings of the corps of
maintenance created by their own labor and capital. What the series of
engines yields over and above what it expends in maintaining itself it
gives to its owners as an income. This is their net return and they
can use it without trenching on their property. The analogy between
the returns from land and those from a self-perpetuating series of
made capital goods is in this particular complete.

_The Source of the Fund for Repairs and Renewals._--The fund for
repairs and renewals must, of course, like the net income itself, be
furnished by instruments that are above the no-rent grade. A machine
will naturally be used as long as it pays anything whatever, and
during the latter part of its career it usually produces less than
mere interest on its cost. So long as the labor and the auxiliary
capital that are combined with the instrument produce by its aid any
more than they would produce if they were withdrawn from it and added,
as marginal increments, to the labor and capital that are working in
connection with good instruments, they will continue to use the
machine and they will abandon it only when it ceases to pay anything
whatever. Out of the total amount it produces before reaching this
point of abandonment comes the amount that is needed as an offset for
the cost of providing a new machine.

_Incorrectness of a Common Statement concerning Rent and Price._--This
brings into view a striking fallacy of what has been current economic
theory. It has been customary to claim that the rent of land "is not
an element in price," although the interest on capital is such an
element. The rent of land is the net product of land; and if interest
be kept distinct from it, this income is the net product of a
permanent stock of capital goods. The relations of these two component
parts of the constant output of goods to the prices of the goods are
identical.

_Proof of the Incorrectness of the Current Statement concerning Rent
and Price._--The vague form of the current statement concerning rent
and price is responsible for much confusion of thought on that
subject. What the statement would mean is that the price of wheat is
not affected by the great contributions to the supply of it which good
lands are making. These contribut