It clings the more tightly to this appearance since it seems to furnish proof that capital possesses a mystic source of self-expansion independent of its process of production and hence of the exploitation of labour, a spring which flows to it from the sphere of circulation. We shall see later that even scientific Political Economy has been deceived by this appearance of things. Various phenomena, it will turn out, give color to this semblance:
1) The capitalist method of calculating profit, in which the negative cause figures a positive one, since with capitals in different spheres of investment, where only the time of circulation are different, a longer time of circulation tends to bring about an increase in prices, in short, serves as one of the causes of equalising profits. 2) The time of circulation is but a phase of the time of turnover; the latter however includes the time of production or reproduction. What is really due to the latter seems to be due to the time of circulation. 3) The conversion of commodities into variable capital (wages) is necessitated by their previous conversion into money. In the accumulation of capital, the conversion into additional variable capital therefore takes place in the sphere of circulation, or during the time of circulation. Consequently it seems that the accumulation thus achieved is owed to the latter.
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.