sufficiently, the exertions of the Salvation Army might create such a demand for tambourines as to make them worth four times their cost of production, whereupon there would instantly be a furious concentration of the instrument-making energy on the manufacture of tambourines; and this concentration would last until the supply had brought down the profit[8] to less than might be gained by gratifying the public craving for trombones. At last, as pianofortes were cheapened until they were no more profitable than harps; then American organs until they were no more profitable than pianos; and then tambourines until they were level with American organs; so eventually trombones will pay no better than tambourines; and a general level of profit will be attained, indicating the proportion in which the instruments are wanted by the public. But to skim off even this level of profit, more of the instruments may be produced in the ascertained proportion until their prices fall to their costs of production, when there will be no profit. Here the production will be decisively checked, since a further supply would cause only a loss; and men can lose money, without the trouble of producing commodities, by the simple process of throwing it out of a window. What occurred with the musical instruments in this illustration occurs in practice with the whole mass of manufactured commodities. Those which are scarce, and therefore relatively high in value, tempt us to produce them until the increase of the supply reduces their value to a point at which there is no more profit to be made out of them than out of other commodities. The general level of profit thus attained is further exploited until the general increase brings down the price of all commodities to their cost of production, the equivalent of which is sometimes called their normal value. And here a glance back to our analysis of the spread of cultivation, and its result in the phenomenon of rent, suggests the question What does the cost of production of a commodity mean? We have seen that, owing to the differences in fertility and advantage of situation between one piece of land and another, cost of production varies from district to district, being highest at the margin of cultivation. But we have also seen how the landlord skims off as economic rent all the advantages gained by the cultivators of superior soils and sites. Consequently, the addition of the landlord’s rent to the expenses of production brings them up even on the best land to the level of those incurred on the worst. Cost of production, then, means cost of production on the margin of cultivation, and is equalized to all producers, since what they may save in labor per commodity is counterbalanced by the greater mass of commodities they must produce in order to bring in the rent. It is only by a thorough grasp of this levelling-down action that we can detect the trick by which the ordinary economist tries to cheat us into