We have now seen that while advancing population tends to advance rent, so all the causes that in a progressive state of society operate to increase the productive power of labor, tend, also, to advance rent, and not to advance wages or interest. The increased production of wealth goes ultimately to the owners of land in increased rent; and, although, as improvement goes on, advantages may accrue to individuals not land holders, which concentrate in their hands considerable portions of the increased produce, yet there is in all this improvement nothing which tends to increase the general return either to labor or to capital.

But there is a cause, not yet adverted to, which must be taken into consideration to fully explain the influence of material progress upon the distribution of wealth.

That cause is the confident expectation of the future enhancement of land values, which arises in all progressive countries from the steady increase of rent, and which leads to speculation, or the holding of land for a higher price than it would then otherwise bring.

We have hitherto assumed, as is generally assumed in elucidations of the theory of rent, that the actual margin of cultivation always coincides with what may be termed the necessary margin of cultivation—that is to say, we have assumed that cultivation extends to less productive points only as it becomes necessary from the fact that natural opportunities are at the more productive points fully utilized.