Now, this normal point of interest, which lies between the necessary maximum and the necessary minimum of the return to capital, must, wherever it rests, be such that all things (such as the feeling of security, desire for accumulation, etc.) considered, the reward of capital and the reward of labor will be equal—that is to say, will give an equally attractive result for the exertion or sacrifice involved. It is impossible, perhaps, to formulate this point, as wages are habitually estimated in quantity and interest in a ratio; but if we suppose a given quantity of wealth to be the produce of a given amount of labor, cooperating for a stated time with a certain amount of capital, the proportion in which the produce would be divided between the labor and the capital would afford a comparison. There must be such a point at, or rather, about, which the rate of interest must tend to settle; since, unless such an equilibrium were effected, labor would not accept the use of capital, or capital would not be placed at the disposal of labor. For labor and capital are but different forms of the same thing—human exertion. Capital is produced by labor; it is, in fact, but labor impressed upon matter—labor stored up in matter, to be released again as needed, as the heat of the sun stored up in coal is released in the furnace. The use of capital in production is, therefore, but a mode of labor. As capital can be used only by being consumed, its use is the expenditure of labor, and for the maintenance of capital, its production by labor must be commensurate with its consumption in aid of labor. Hence the principle that, under circumstances which permit free competition, operates to bring wages to a common standard and profits to a substantial equality—the principle that men will seek to gratify their desires with the least exertion—operates to establish and maintain this equilibrium between wages and interest. This natural relation between interest and wages—this equilibrium at which both will represent equal returns to equal exertions—may be stated in a form which suggests a relation of opposition; but this opposition is only apparent. In a partnership between Dick and Harry, the statement that Dick receives a certain proportion of the profits implies that the portion of Harry is less or greater as Dick’s is greater or less; but where, as in this case, each gets only what he adds to the common fund, the increase of the portion of the one does not decrease what the other receives. And this relation fixed, it is evident that interest and wages must rise and fall together, and that interest cannot be increased without increasing wages; nor wages lowered without depressing interest. For if wages fall, interest must also fall in proportion, else it becomes more profitable to turn labor into capital than to apply it directly; while, if interest falls, wages must likewise proportionately fall, or else the increment of capital would be checked.