Investigation of the circulation of money in society shows that the individual capitalist can never invest the whole of his money capital in production but must always keep a certain money reserve to be employed as variable capital, i.e. as wages. Further, he must keep a capital reserve for the purchase of means of production at any given period, and in addition, he must have a cash reserve for his personal consumption.

The process of reproducing the total social capital thus entails the necessity of producing and reproducing the substance of money. Money is also capital, for Marx’s diagram which we have discussed before, conceives of no other than capitalist production. Thus the diagram seems incomplete. We ought to add a further department, that of production of the means of exchange, to the other two large departments of social production [those of means of production (I) and of consumer goods (II)]. It is, indeed, a characteristic feature of this third department that it serves neither the purposes of production nor those of consumption, merely representing social labour in an undifferentiated commodity that cannot be used. Though money and its production, like the exchange and production of commodities, are much older than the capitalist mode of production, it was only the latter which made the circulation of money a general form of social circulation, and thus the essential element of the social reproductive process. We can only obtain a comprehensive diagram of the essential points of capitalist production if we demonstrate the original relationship between the production and reproduction of money and the two other departments of social production.

Here, however, we deviate from Marx. He included the production of gold (we have reduced the total production of money to the production of gold for the sake of simplicity) in the first department of social production.

‘The production of gold, like that of metals generally, belongs to department I, which occupies itself with means of production.’[92]

This is correct only in so far as the production of gold is the production of metal for industrial purposes (jewellery, dental stoppings, etc.). But gold in its capacity as money is not a metal but rather an embodiment of social labour in abstracto. Thus it is no more a means of production than it is a consumer good. Besides, a mere glance at the diagram of reproduction itself shows what inconsistencies must result from confusing means of exchange with means of production. If we add a diagrammatic representation of the annual production of gold as the substance of money to the two departments of social production, we get the following three sets of figures:

I.4,000c+1,000v+1,000s=6,000means of production
II.2,000c+500v+500s=3,000means of subsistence
III.20c+5v+5s=30means of exchange

This quantity of value of 30, chosen by Marx as an example, obviously does not represent the quantity of money which circulates annually in society; it only stands for that part which is annually reproduced, the annual wear and tear of the money substance which, on the average, remains constant so long as social reproduction remains on the same level. The turnover of capital goes on in a regular manner and the realisation of commodities proceeds at an equal pace. If we consider the third line as an integral part of the first one, as Marx wants us to do, the following difficulty arises: the constant capital of the third department consists of real and concrete means of production, premises, tools, auxiliary materials, vessels, and the like, just as it does in the two other departments. Its product, however, the 30g which represent money, cannot operate in its natural form as constant capital in any process of production. If we therefore include this 30g as an essential part of the product of Department I (6,000 means of production) the means of production will show a social deficit of this size which will prevent Departments I and II from resuming their reproduction on the old scale. According to the previous assumption—which forms the foundation of Marx’s whole diagram—reproduction as a whole starts from the product of each department in its actual use-form. The proportions of the diagram are based upon this assumption; without it, they dissolve in chaos. Thus the first fundamental relation of value is based upon the equation: I(6,000) equals I(4,000c) + II(2,000c). This cannot apply to the product III(30g), since neither department can use gold as a means of production [say, in the proportion of I(20c) + II(10c)]. The second fundamental relation derived from this is based upon the equation I(1,000v) + I(1,000s) = II(2,000c). This would mean, with regard to the production of gold, that as many consumer goods are taken from Department II as there are means of production supplied to it. But this is equally untrue. Though the production of gold removes concrete means of production from the total social product and uses them as its constant capital, though it takes concrete consumer goods for the use of its workers and capitalists, corresponding to its variable capital and surplus value, the product it supplies yet cannot operate in any branch of production as a means of production, nor is it a consumer good, fit for human consumption. To include the production of money in the activities of Department I, therefore, is to run counter to all the general proportions which express the relations of value in Marx’s diagram, and to diminish the diagram’s validity.

The attempt by Marx to find room for the production of gold within Department I (means of production) moreover leads to dubious results. The first act of circulation between this new sub-Department (called by Marx Ig) and Department II (consumer goods) consists as usual in the workers’ purchase of consumer goods from Department II with the money obtained as wages from the capitalists. This money is not yet a product of the new period of production. It has been reserved by the capitalists of Department Ig out of the money contained in their product of an earlier period. This, indeed, is the normal procedure. But now Marx allows the capitalists of Department II to buy gold from Ig with the money they have reserved, gold as a commodity material to the value of 2. This is a leap from the production of money into the industrial production of gold which is no more to do with the problem of the production of money than with the production of boot-polish. Yet out of the 5 Ig v that have been reserved, 3 still remain, and as the capitalist, unable to use them as constant capital, does not know what to do with them, Marx arranges for him to add them on to his own reserve of money. Marx further finds the following way out to avoid a deficit in the constant capital of II which must be exchanged completely against the means of production (Iv + Is):

‘Therefore, this money must be entirely transferred from IIc to IIs, no matter whether it exists in necessities of life or articles of luxury, and vice versa, a corresponding value of commodities must be transferred from IIs to IIc. Result: A portion of the surplus-value is accumulated as a hoard of money.’[93]

A strange result, in all conscience! We have achieved an increase in money, a surplus of the money substance, by simply confining ourselves to the annual wear and tear of the money fund. This surplus value comes into existence, for some unknown reason, at the expense of the capitalists in the consumer goods department. They practise abstinence, not because they may want to expand their production of surplus value, let us say, but in order to secure a sufficient quantity of consumer goods for the workers engaged in the production of gold.