But all this dubious subterfuge does not solve the problem, which, simply stated, is this: Assume the market-price of grain (which in this inquiry stands for products of the soil in general) to be sufficient to permit taking portions of soil A under cultivation and that the capital invested in these new fields could return the price of production, i.e., replace capital plus average profit. Thus assume that conditions exist for the normal expansion of capital on soil A. Is this sufficient? Can this capital then really be invested? Or must the market-price rise to the point where even the worst soil A yields rent? In other words, does the landowner’s monopoly hinder the investment of capital which would not be the case from the purely capitalist standpoint in the absence of this monopoly? It follows from the way in which the question itself is posed that if, e.g., additional capitals are invested in the old leaseholds, yielding the average profit at the given market-price, but no rent, this circumstance in no way answers the question whether capital may now really be invested in soil A, which also yields the average profits but no rent. But this is precisely the question before us. The fact that additional investments of capital not yielding any rent do not satisfy the demand is proved by the necessity of taking new land of soil type A under cultivation. Just two alternatives are possible if the additional cultivation of soil A takes place only in so far as it yields rent, that is, yields more than the price of production. Either the market-price must be such that even the last additional investments of capital in the old leaseholds yield surplus-profit, whether pocketed by the farmer or by the landlord. This rise in price and this surplus-profit from the last additional investments of capital would then result from the fact that soil A cannot be cultivated without yielding rent. For if the price of production were sufficient for cultivation to take place, merely yielding average profit, the price would not have risen so high, and competition from new plots would have been felt as soon as they just yielded this price of production. Competing with the additional investments in old leaseholds not yielding any rent would then be investments in soil A, which likewise do not yield any rent. — Or, the last investments in the old leaseholds do not yield any rent, but nevertheless the market-price has risen sufficiently to make it possible for soil A to be taken under cultivation and to yield rent. In this case, the additional investment of capital not yielding any rent was only possible because soil A cannot be cultivated until the market-price permits it to pay rent. Without this condition, its cultivation would have already begun at a lower price level; and those later investments of capital in the old leaseholds, which require the high market-price in order to yield the usual profit without rent, could not have taken place. At the high market-price, it is true, they yield only the average profit. At a lower market-price, which would have become the regulating price of production from the time soil A came under cultivation, they would thus not have yielded this average profit, i.e., the investments would thus not have taken place at all under such conditions. In this way, the rent from soil A would indeed constitute differential rent compared with the investments in the old leaseholds not yielding any rent. But that such differential rent is formed on the land areas of A is but a consequence of the fact that the latter are not at all available to cultivation, unless they yield rent; i.e., that the necessity for this rent exists, which, in itself, is not determined by any differences in soil types, and which constitutes the barrier to possible investment of additional capitals in the old leaseholds. In either case, the rent from soil A would not be simply a consequence of the rise in grain prices, but, conversely, the fact that the worst soil must yield rent in order to make its cultivation at all possible, would be the cause for the rise in the grain price to the point where this condition may be fulfilled.