In the case of this third assumption, it is again immaterial whether the additional second investments of capital are uniformly distributed among the various soils or not; whether the decreasing production of surplus-profit takes place proportionately or not; whether the additional investments of capital are all in the same rent-bearing type of soil, or whether they are distributed equally or unequally among rent-bearing plots of land of varying quality. All these circumstances are immaterial for the law that is to be developed. The only assumption is that additional investments of capital yield surplus-profit upon any one of the rent-bearing soils, but in decreasing proportion to the amount of the increase in capital. The limits of this decrease, in the table before us, are between 4 quarters = £12, the output from the first outlay of capital on the best soil D, and 1 quarter = £3, the output from the same outlay of capital in the worst soil A. The output from the best soil in case of the investment of capital I constitutes the top limit, and the output from the same outlay of capital in the worst soil A, which yields neither rent nor surplus-profit, is the bottom limit of output, which successive investments of capital yield upon any of the soil types producing surplus-profit with decreasing productivity of successive investments of capital. Just as assumption II corresponds to the case in which new plots of the same quality are added from the better soils to the cultivated area, in which the quantity of any one of the cultivated soils is increased, so assumption III corresponds to the case in which additional plots are cultivated whose various degrees of fertility are distributed among soils ranging from D to A, i.e., from the best to the worst soils. If the successive outlays of capital are made exclusively in soil D, they may include the existing differences between D and A, then differences between D and C, and likewise between D and B. If they are all made in soil C, then only differences between C and A, and C and B; if exclusively in B, then only differences between B and A.