Within the sphere of circulation capital passes through the two antithetical phases C — M and M — C; it is immaterial in what order. Hence its time of circulation is likewise divided into two parts, viz.: the time it requires for its conversion from commodities into money, and that which it requires for its conversion from money into commodities. We have already learned from the analysis of simple circulation of commodities (Buch I, Kap. III) [English edition: Ch. III. — Ed.] that C — M, the sale, is the most difficult part of its metamorphosis and that therefore under ordinary conditions it takes up the greater part of its time of circulation. As money, value exists in its always convertible form. As a commodity it must first be transformed into money before it can assume this form of direct convertibility and hence of constant readiness for action. However, in capital’s process of circulation, its phase M — C has to do with its transformation into commodities which constitute definite elements of productive capital in a given enterprise. The means of production may not be available in the market and must first be produced or they must be procured from distant markets or their ordinary supply has become irregular or prices have changed, etc., in short there are a multitude of circumstances which are not noticeable in the simple change of form M — C, but which nevertheless requires now more, now less time also for this part of the circulation phase. C — M and M — C may be separate not only in time but also in space; the market for buying and the market for selling may be located apart. In the case of factories for instance buyer and seller are frequently different persons. In the production of commodities, circulation is as necessary as production itself, so that circulation agents are just as much needed as production agents. The process of reproduction includes both functions of capital, therefore it includes the necessity of having representatives of these functions, either in the person of the capitalist himself or of wage-labourers, his agents. But this furnishes no ground for confusing the agents of circulation with those of production, any more than it furnishes ground for confusing the functions of commodity-capital and money-capital with those of productive capital. The agents of circulation must be paid by the agents of production. But the capitalists, who sell to and buy from one another, create neither values nor products by these acts, this state of affairs is not changed if they are enabled or compelled by the volume of their business to shift this function on to others. In some businesses the buyers and sellers get paid in the form of percentages on the profits. All talk about their being paid by the consumer does not help matters. The consumers can pay only in so far as they, as agents of production, produce an equivalent in commodities for themselves or appropriate it from production agents either on the basis of some legal title (as their co-partners, etc.) or by personal services.