First, it was seen that the average rent per acre, or the average rate of rent on capital, may increase with an extension of cultivation when prices are stationary and the differential fertility of the cultivated plots of land remains unaltered. As soon as all the land in a given country has been appropriated, and investments of capital in land, cultivation, and population have reached a definite level — all given conditions as soon as the capitalist mode of production becomes the prevailing one and also encompasses agriculture — the price of uncultivated land of varying quality (merely assuming differential rent to exist) is determined by the price of the cultivated plots of land of the same quality and equivalent location. The price is the same — after deducting the cost of bringing the new land into cultivation — even though this land does not yield any rent. The price of the land is, indeed, nothing but the capitalised rent. But even in the case of cultivated land, the price pays only for future rents, as, for instance, when the prevalent interest rate is 5% and the rent for twenty years is paid at one time in advance. When land is sold, it is sold as land yielding rent, and the prospective character of the rent (which is here considered as a product of the soil, but it only seems to be that) does not distinguish the uncultivated from the cultivated land. The price of the uncultivated land, like its rent the price of which represents the contracted form of the latter is quite illusory as long as the land is not actually used. But it is thus determined a priori and is realised as soon as a purchaser is found. Hence, while the actual average rent in a given country is determined by its actual average annual rental and the relation of the latter to the total cultivated area, the price of the uncultivated land is determined by the price of the cultivated land, and is therefore but a reflection of the capital invested in the cultivated land and the results obtained therefrom. Since all land with the exception of the worst yields rent (and this rent, as we shall see under the head of differential rent II, increases with the quantity of capital and corresponding intensity of cultivation), the nominal price of uncultivated plots of land is thus formed, and they thus become commodities, a source of wealth for their owners. This explains at the same time, why the price of land increases in a whole region, even in the uncultivated part (Opdyke). Land speculation, for instance, in the United States, is based solely on this reflection thrown by capital and labour on uncultivated land.