In the exchange between I (1,000v + 1,000s) and 2,000 IIc it must be first noted that the sum of values I(v + s) does not contain any constant element of value, hence also no element of value to replace wear and tear, i.e., value that has been transmitted from the fixed component of
 the constant capital to the commodities in whose bodily form v + s
 exist. On the other hand this element exists in IIc, and it is precisely a
 part of this value-element that owes its existence to fixed capital which
 is not to be converted immediately from the money-form into its bodily
 form, but has first to persist in the form of money. The exchange
 between I (1,000v + 1,000s) and 2,000 IIc, therefore, at once presents the difficulty that the means of production of I, in whose bodily form the 2,000(v + s) exist, are to be exchanged to the full value of 2,000 for an equivalent in articles of consumption II, while on the other hand the
 2,000 IIc of articles of consumption cannot be exchanged at their full
 value for means of production I (1,000v + 1,000s) because an aliquot part of their value — equal to the wear and tear, or the value depreciation
 of the fixed capital that is to be replaced — must first be precipitated in
 the form of money that will not function any more as a medium of
 circulation during the current period of annual reproduction, which alone
 we are examining. But the money paying for this element of wear and
 tear incorporated in the commodity-value 2,000 IIc can come only from
 department I, since II cannot pay for itself but effects payment precisely
 by selling its goods, and since presumably I(v + s) buys the whole of the
 commodities 2,000 IIc. Hence class I must by means of this purchase
 convert that wear and tear into money for II. But according to the law
 previously evolved, money advanced to the circulation returns to the
 capitalist producer who later on throws an equal amount of commodities
 into circulation. It is evident that in buying IIc, I cannot give II
 commodities worth 2,000 and a surplus amount of money on top of that
 once and for all (without any return of the same by way of the operation
 of exchange). Otherwise I would buy the commodity mass II above its
 value. If II actually exchanges its 2,000c for I (1,000v + 1,000s), it has no further claims on I, and the money circulating in this exchange returns to either I or II, depending on which of them threw it into
 circulation, i.e., which of them acted first as buyer. At the same time II
 would have reconverted the entire value of its commodity-capital into the
 bodily form of means of production, while our assumption is that after its
 sale it would not reconvert an aliquot portion of it during the current
 period of annual reproduction from money into the bodily form of fixed
 components of its constant capital. A money balance in favour of II could
 arise only if it sold 2,000 worth to I and bought less than 2,000 from I,
 say only 1,800. In that case I would have to make good the debit
 balance by 200 in money, which would not flow back to it, because it
 would not have withdrawn from circulation the money it had advanced
 to it by throwing into it commodities equal to 200. In such an event we
 would have a money-fund for II, placed to the credit of the wear and tear
 of its fixed capital. But then we would have an over-production of means
 of production in the amount of 200 on the other side, the side of I, and
 the basis of our scheme would be destroyed, namely reproduction on the
 same scale, where complete proportionality between the various systems
 of production is assumed. We would only have done away with one
 difficulty in order to create another one much worse.