It should be recollected that prices always vary in the market, and in the first instance, through the comparative state of demand and supply. Although cloth could be furnished at 40_s._ per yard, and give the usual profits of stock, it may rise to 60 or 80_s._ from a general change of fashion, or from any other cause which should suddenly and unexpectedly increase the demand, or diminish the supply of it. The makers of cloth will for a time have unusual profits, but capital will naturally flow to that manufacture, till the supply and demand are again at their fair level, when the price of cloth will again sink to 40_s._, its natural or necessary price. In the same manner, with every increased demand for corn, it may rise so high as to afford more than the general profits to the farmer. If there be plenty of fertile land, the price of corn will again fall to its former standard, after the requisite quantity of capital has been employed in producing it, and profits will be as before; but if there be not plenty of fertile land, if, to produce this additional quantity, more than the usual quantity of capital and labour be required, corn will not fall to its former level. Its natural price will be raised, and the farmer, instead of obtaining permanently larger profits, will find himself obliged to be satisfied with the diminished rate which is the inevitable consequence of the rise of wages, produced by the rise of necessaries.
The natural tendency of profits then is to fall; for, in the progress of society and wealth, the additional quantity of food required is obtained by the sacrifice of more and more labour. This tendency, this gravitation as it were of profits, is happily checked at repeated intervals by the improvements in machinery, connected with the production of necessaries, as well as by discoveries in the science of agriculture which enable us to relinquish a portion of labour before required, and therefore to lower the price of the prime necessary of the labourer. The rise in the price of necessaries and in the wages of labour is however limited; for as soon as wages should be equal (as in the case formerly stated) to 720_l._, the whole receipts of the farmer, there must be an end of accumulation; for no capital can then yield any profit whatever, and no additional labour can be demanded, and consequently population will have reached its highest point. Long indeed before this period, the very low rate of profits will have arrested all accumulation, and almost the whole produce of the country, after paying the labourers, will be the property of the owners of land and the receivers of tithes and taxes.