THE PROBLEM OF RENT 10%

occurred through the recourse to second-grade soils. Without
 supposing so great a change as a doubling of the outlay
on each acre, some increase of the capital and labour may
realise returns in the proportion indicated by the figures
used in reference to a supposed doubling, and the effects on
the proportion of the original 25 bushels needed to pay the
expenses of the cultivation of the soil will be unchanged.
Thus, alongside of, and concurrently with, the advance of
cultivation to inferior soils, we have a more intense application
 of capital and labour to soils already cultivated. In
each case it is seen that the surplus available for rent is
equal to the excess of the actual produce over the amount
needed to cover the expenses of cultivation. To state the
amount of rent with reference to those expenses, then, is by
no means in conflict with the conception obtained by means
of illustrations such as those we have now been considering.
How do these ideas apply to the case of land used for
building purposes, or to mining properties? First, let us
consider building land. Here, situation is practically the
one element in determining the differences in value of
different sites of equal area. But, as in the case of
agricultural land, we may properly give attention both to the
differences between different sites and to the differences in
the various modes of utilisation of the same site. A site in
a business thoroughfare affords opportunity for transacting
a larger amount of profit-yielding business than a similar
site in a side-street. There is a greater excess of income
over expenses in utilising the one than in utilising the other,
and that excess is the measure of how much more may profitably
 be offered for the use of the more convenient site.
In planning the building to be erected on a given site, the
expenditure will be considered in relation to the revenueyielding
 capacity of the accommodation secured. The limit
of expenditure will be reached when additional outlay adds,
to the prospective yield, not more than enough to cover
interest on the outlay and a fair remuneration for the risk
undertaken in connection with it. The total yield will bear
a greater proportion to the total outlay than the marginal
vield thus conceived to the marginal outlay, and the