In some of these cases, the increase in the price of agricultural produce, compared with the cost of the instruments of production, appears from what has been said to be only temporary; and in these instances it will often give a considerable stimulus to cultivation, by an increase of agricultural profits, without showing itself much in the shape of rent. It hardly ever fails, however, to increase rent ultimately. The increased capital, which is employed in consequence of the opportunity of making great temporary profits, can seldom if ever be entirely removed from the land, at the expiration of the current leases; and, on the renewal of these leases, the landlord feels the benefit of it in the increase of his rents. Whenever then, by the operation of the four causes above mentioned, the difference between the price of produce and the cost of the instruments of production increases, the rents of land will rise. It is, however, not necessary that all these four causes should operate at the same time; it is only necessary that the difference here mentioned should increase. If, for instance, the price of produce were to rise, while the wages of labour, and the price of the other branches of capital did not rise in proportion, and at the same time improved modes of agriculture were coming into general use, it is evident that this difference might be increased, although the profits of agricultural stock were not only undiminished, but were to rise decidedly higher. Of the great additional quantity of capital employed upon the land in this country, during the last twenty years, by far the greater part is supposed to have been generated on the soil, and not to have been brought from commerce or manufactures. And it was unquestionably the high profits of agricultural stock, occasioned by improvements in the modes of agriculture, and by the constant rise of prices, followed only slowly by a proportionate rise in the different branches of capital, that afforded the means of so rapid and so advantageous an accumulation. In this case cultivation has been extended, and rents have risen, although one of the instruments of production, capital, has been dearer. In the same manner a fall of profits and improvements in agriculture, or even one of them separately, might raise rents, notwithstanding a rise of wages. It may be laid down then as a general truth, that rents naturally rise as the difference between the price of produce and the cost of the instruments of production increases. It is further evident, that no fresh land can be taken into cultivation till rents have risen, or would allow of a rise upon what is already cultivated.