This is simply the question, before discussed, whether, if only one class of land were cultivated, some agricultural capital would pay rent or not. It all depends on the fact whether population—and so the demand for food—has increased to the point where it calls out a recognition of the diminishing productiveness of the soil. In that case different capitals would be invested, so that there would be different returns to the same amount of capital; and the prior or more advantageous investments of capital on the land would yield more than the ordinary rate of profit, which could be claimed as rent. A. L. Perry(184) admits the law of diminishing returns, but holds that, “as land is capital, and as every form of capital may be loaned or rented, and thus become fruitful in the hands of another, the rent of land does not differ essentially in its nature from the rent of buildings in cities, or from the interest of money.” Henry George admits Ricardo’s law of rent to its full extent, but very curiously says: “Irrespective of the increase of population, the effect of improvements in methods of production and exchange is to increase rent.... The effect of labor-saving improvements will be to increase the production of wealth. Now, for the production of wealth, two things are required, labor and land. Therefore, the effect of labor-saving improvements will be to _extend the demand for land_, and, wherever the limit of the quality of land in use is reached, to bring into cultivation lands of less natural productiveness, or to extend cultivation on the same lands to a point of lower natural productiveness. And thus, while the primary effect of labor-saving improvements is to increase the power of labor, the secondary effect is to extend cultivation, and, where this lowers the margin of cultivation, to increase rent.”(185) Francis Bowen(186) rejects Ricardo’s law, and says, “Rent depends, not on the increase, but on the distribution, of the population”—asserting that the existence of large cities and towns determines the amount of rent paid by neighboring land.(187) § 6. Rent does not enter into the Cost of Production of Agricultural Produce.