 In the first instance real circulation consists of a mass of random purchases and sales taking place simultaneously. In both purchase and sale commodities and money confront each other in the same way; the seller represents the commodity, the buyer the money. As a means of circulation money therefore appears always as a means of purchase, and this obscures the fact that it fulfils different functions in the antithetical phases of the metamorphosis of commodities. Money passes into the hands of the seller in the same transaction which transfers the commodity into the hands of the buyer. Commodity and money thus move in opposite directions, and this change of places in the course of which the commodity crosses over to one side and money to the other occurs simultaneously at an indefinite number of points along the entire surface of bourgeois society. But the first move of the commodity in the sphere of circulation is also its last move.  No matter whether the commodity changes its position because gold is attracted by it (C M) or because it is attracted by gold (M C), in consequence of the single move, the single change of place, it falls out of the sphere of circulation into that of consumption. Circulation is a perpetual movement of commodities, though always of different commodities, and each commodity makes but one move. Each commodity begins the second phase of its circuit not as the same commodity, but as a different commodity, i.e., gold. The movement of the metamorphosed commodity is thus the movement of gold. The same coin or the identical bit of gold which in the transaction C M changed places with a commodity becomes in turn the starting point of M C, and thus for the second time changes places with another commodity. Just as it passed from the hands of B, the buyer, into those of A, the seller, so now it passes from the hands of A, who has become a buyer, into those of C. The changes in the form of a commodity, its transformation into money and its retransformation from money, in other words the movement of the total metamorphosis of a commodity, accordingly appear as the extrinsic movement of a single coin which changes places twice, with two different commodities. However scattered and fortuitous the simultaneous purchases and sales may be, a buyer is always confronted by a seller in actual circulation, and the money which takes the place of the commodity sold must already have changed places once with another commodity before reaching the hands of the buyer. On the other hand, sooner or later the money will pass again from the hands of the seller who has become a buyer into those of a new seller, and its repeated changes of place express the interlocking of the metamorphoses of commodities. The same coins therefore proceed always in the opposite direction to the commodities moved from one point of the circuit to another; some coins move more frequently, others less frequently, thus describing a longer or shorter curve. The different movements of one and the same coin can follow one another only temporally, just as conversely the multiplicity and fragmentation of the purchases and sales are reflected in the simultaneous and spatially concurrent changes of place of commodity and money. The simple form of commodity circulation, C M C, takes place when money passes from the hands of the buyer into those of the seller and from the seller who has become a buyer into the hands of a new seller. This concludes the metamorphosis of the commodity and hence the movement of money in so far as it is the expression of this metamorphosis. But since there are new use-values produced continuously in the form of commodities, which must therefore be thrown continuously afresh into the sphere of circulation, the circuit C M C is renewed and repeated by the same commodity-owners. The money they have spent as buyers returns to them when they once more become sellers of commodities. The perpetual renewal of commodity circulation is reflected in the fact that over the entire surface of bourgeois society money not only circulates from one person to another but that at the same time it describes a number of distinct small circuits, starting from an infinite variety of points and returning to the same points, in order to repeat the movement afresh. As the change of form of the commodity appears as a mere change in place of money, and the continuity of the movement of circulation belongs entirely to the monetary side because the commodity always makes only one step in the direction opposite to that of money, money however invariably making the second step for the commodity to complete the motion begun by the commodity so the entire movement appears to be initiated by money, although during the sale the commodity causes the money to move, thus bringing about the circulation of the money in the same way as during the purchase the money brings about the circulation of the commodity. Since moreover money always confronts commodities as a means of purchase and as such causes commodities to move merely by realising their prices, the entire movement of circulation appears to consist of money changing places with commodities by realising their prices either in separate transactions which occur simultaneously, side by side, or successively when the same coin realises the prices of different commodities one after another. If, for example, one examines C M C' M C'' M C''', etc., and disregards the qualitative aspects, which become unrecognisable in actual circulation, there emerges only the same monotonous operation. After realising the price of C, M successively realises the prices of C', C'', etc., and the commodities C', C'', C''', etc., invariably take the place vacated by money. It thus appears that money causes the circulation of commodities by realising their prices. While it serves to realise prices, money itself circulates continuously, sometimes moving merely to a different place, at other times tracing a curve or describing a small cycle in which the points of departure and of return are identical. As a medium of circulation it has a circulation of its own. The movement and changing forms of the circulating commodities thus appear as the movement of money mediating the exchange of commodities, which are in themselves immobile. The movement of the circulation process of commodities is therefore represented by the movement of money as the medium of circulation, i.e., by the circulation of money. Just as commodity-owners presented the products of individual labour as products of social labour, by transforming a thing, i.e., gold, into the direct embodiment of labour-time in general and therefore into money, so now their own universal movement by which they bring about the exchange of the material elements of their labour confronts them as the specific movement of a thing, i.e., as the circulation of gold. The social movement is for the commodity owners on the one hand an external necessity and on the other merely a formal intermediary process enabling each individual to obtain different use-values of the same total value as that of the commodities which he has thrown into circulation. The commodity begins to function as a use-value when it leaves the sphere of circulation, whereas the use-value of money as a means of circulation consists in its very circulation. The movement of the commodity in the sphere of circulation is only an insignificant factor, whereas perpetual rotation within this sphere becomes the function of money. The specific function which it fulfils within circulation gives money as the medium of circulation a new and distinctive aspect, which now has to be analysed in more detail. First of all, it is evident that the circulation of money is an infinitely divided movement, for it reflects the infinite fragmentation of the process of circulation into purchases and sales, and the complete separation of the complementary phases of the metamorphosis of commodities. It is true that a recurrent movement, real circular motion, takes place in the small circuits of money in which the point of departure and the point of return are identical; but in the first place, there are as many points of departure as there are commodities, and their indefinite multitude balks any attempt to check, measure and compute these circuits. The time which passes between the departure from and the return to the starting point is equally uncertain. It is, moreover, quite irrelevant whether or not such a circuit is described in a particular case. No economic fact is more widely known than that somebody may spend money without receiving it back. Money starts its circuit from an endless multitude of points and returns to an endless multitude of points, but the coincidence of the point of departure and the point of return is fortuitous, because the movement C M C does not necessarily imply that the buyer becomes a seller again. It would be even less correct to depict the circulation of money as a movement which radiates from one centre to all points of the periphery and returns from all the peripheral points to the same centre. The so-called circuit of money, as people imagine it, simply amounts to the fact that the appearance of money and its disappearance, its perpetual movement from one place to another, is everywhere visible. When considering a more advanced form of money used to mediate circulation, e.g., bank-notes, we shall find that the conditions governing the issue of money determine also its reflux. But as regards simple money circulation it is a matter of chance whether a particular buyer becomes a seller once again. Where actual circular motions are taking place continuously in the sphere of simple money circulation, they merely reflect the more fundamental processes of production, for instance, with the money which the manufacturer receives from his banker on Friday he pays his workers on Saturday, they immediately hand over the larger part of it to retailers, etc., and the latter return it to the banker on Monday. We have seen that money simultaneously realises a given sum of prices comprising the motley purchases and sales which coexist in space, and that it changes places with each commodity only once. But, on the other hand, in so far as the movements of complete metamorphoses of commodities and the concatenation of these metamorphoses are reflected in the movement of money, the same coin realises the prices of various commodities and thus makes a larger or smaller number of circuits. Hence, if we consider the process of circulation in a country during a definite period, for instance a day, then the amount of gold required for the realisation of prices and accordingly for the circulation of commodities is determined by two factors: on the one hand, the sum total of prices and, on the other hand, the average number of circuits which the individual gold coins make. The number of circuits or the velocity of money circulation is in its turn determined by, or simply reflects, the average velocity of the commodities passing through the various phases of their metamorphosis, the speed with which the metamorphoses constituting a chain follow one another, and the speed with which new commodities are thrown into circulation to replace those that have completed their metamorphosis. Whereas during the determination of prices the exchange-value of all commodities is nominally turned into a quantity of gold of the same value and in the two separate transactions, M C and C M, the same value exists twice, on the one hand in the shape of commodities and on the other in the form of gold; yet gold as a medium of circulation is determined not by its isolated relation to individual static commodities, but by its dynamic existence in the fluid world of commodities. The function of gold is to represent the transformation of commodities by its changes of place, in other words to indicate the speed of their transformation by the speed with which it moves from one point to another. Its function in the process as a whole thus determines the actual amount of gold in circulation, or the actual quantity which circulates. Commodity circulation is the prerequisite of money circulation; money, moreover, circulates commodities which have prices, that is commodities which have already been equated nominally with definite quantities of gold. The determination of the prices of commodities presupposes that the value of the quantity of gold which serves as the standard measure, or the value of gold, is given. According to this assumption, the quantity of gold required for circulation is in the first place determined therefore by the sum of the commodity-prices to be realised. This sum, however, is in its turn determined by the following factors: 1. the price level, the relative magnitude of the exchange-values of commodities in terms of gold, and 2. the quantity of commodities circulating at definite prices, that is the number of purchases and sales at given prices.  If a quarter of wheat costs 60s., then twice as much gold is required to circulate it or to realise its price as would be required if it cost only 30s. Twice as much gold is needed to circulate 500 quarters at 60s. as is needed to circulate 250 quarters at 60s. Finally only half as much gold is needed to circulate 10 quarters at 100s. as is needed to circulate 40 quarters at 50s. It follows therefore that the quantity of gold required for the circulation of commodities can fall despite rising prices, if the mass of commodities in circulation decreases faster than the total sum of prices increases, and conversely the amount of means of circulation can increase while the mass of commodities in circulation decreases provided their aggregate prices rise to an even greater extent. Thus excellent investigations carried out in great detail by Englishmen have shown that in England, for instance, the amount of money in circulation grows during the early stages of a grain shortage, because the aggregate price of the smaller supply of grain is larger than was the aggregate price of the bigger supply of grain, and for some time the other commodities continue to circulate as before at their old prices. The amount of money in circulation decreases, however, at a later stage of the grain shortage, because along with the grain either fewer commodities are sold at their old prices, or the same amount of commodities is sold at lower prices. But the quantity of money in circulation is, as we have seen, determined not only by the sum of commodity-prices to be realised, but also by the velocity with which money circulates, i.e., the speed with which this realisation of prices is accomplished during a given period. If in one day one and the same sovereign makes ten purchases each consisting of a commodity worth one sovereign, so that it changes hands ten times, it transacts the same amount of business as ten sovereigns each of which makes only one circuit a day.  The velocity of circulation of gold can thus make up for its quantity: in other words, the stock of gold in circulation is determined not only by gold functioning as an equivalent alongside commodities, but also by the function it fulfils in the movement of the metamorphoses of commodities. But the velocity of currency can make up for its quantity only to a certain extent, for an endless number of separate purchases and sales take place simultaneously at any given moment. If the aggregate prices of the commodities in circulation rise, but to a smaller extent than the velocity of currency increases, then the volume of money in circulation will decrease. If, on the contrary, the velocity of circulation decreases at a faster rate than the total price of the commodities in circulation, then the volume of money in circulation will grow. A general fall in prices accompanied by an increase in the quantity of the medium of circulation and a general rise in prices accompanied by a decrease in the quantity of the medium of circulation are among the best documented phenomena in the history of prices. But the causes occasioning a rise in the level of prices and at the same time an even larger rise in the velocity of currency, as also the converse development, lie outside the scope of an investigation into simple circulation. We may mention by way of illustration that in periods of expanding credit the velocity of currency increases faster than the prices of commodities, whereas in periods of contracting credit the velocity of currency declines faster than the prices of commodities. It is a sign of the superficial and formal character of simple money circulation that the quantity of means of circulation is determined by factors such as the amount of commodities in circulation, prices, increases or decreases of prices, the number of purchases and sales taking place simultaneously, and the velocity of currency all of which are contingent on the metamorphosis proceeding in the world of commodities, which is in turn contingent on the general nature of the mode of production, the size of the population, the relation of town and countryside, the development of the means of transport, the more or less advanced division of labour, credit, etc., in short on circumstances which lie outside the framework of simple money circulation and are merely mirrored in it. If the velocity of circulation is given, then the quantity of the means of circulation is simply determined by the prices of commodities. Prices are thus high or low not because more or less money is in circulation, but there is more or less money in circulation because prices are high or low. This is one of the principal economic laws, and the detailed substantiation of it based on the history of prices is perhaps the only achievement of the post-Ricardian English economists. Empirical data show that, despite temporary fluctuations, and sometimes very intense fluctuations,  over longer periods the level of metallic currency or the volume of gold and silver in circulation in a particular country may remain on the whole stable, deviations from the average level amounting merely to small oscillations. This phenomenon is simply due to the contradictory nature of the factors determining the volume of money in circulation. Changes occurring simultaneously in these factors neutralise their effects and everything remains as it was. The law that, if the speed of circulation of money and the sum total of the commodity-prices are given, the amount of the medium of circulation is determined, can also be expressed in the following way: if the exchange-values of commodities and the average speed of their metamorphoses are given, then the quantity of gold in circulation depends on its own value. Thus, if the value of gold, i.e. the labour-time required for its production, were to increase or to decrease, then the prices of commodities would rise or fall in inverse proportion and, provided the velocity remained unchanged, this general rise or fall in prices would necessitate a larger or smaller amount of gold for the circulation of the same amount of commodities. The result would be similar if the previous standard of value were to be replaced by a more valuable or a less valuable metal. For instance, when, in deference to its creditors and impelled by fear of the effect the discovery of gold in California and Australia might have, Holland replaced gold currency by silver currency, 14 to 15 times more silver was required than formerly was required of gold to circulate the same volume of commodities. Since the quantity of gold in circulation depends upon two variable factors, the total amount of commodity-prices and the velocity of circulation, it follows that it must be possible to reduce and expand the quantity of metallic currency; in short, in accordance with the requirements of the process of circulation, gold must sometimes be put into circulation and sometimes withdrawn from it. We shall see later how these conditions are realized in the process of circulation.
Economic Manuscripts: The Circulation of Money