Since the products created by B, B', B'', etc. (I), re-enter in kind into their own process, it goes without saying that pro tanto a portion of their own surplus-product is transferred directly (without any intervention of circulation) to their productive capital and becomes an additional element of constant capital. And pro tanto they do not effect the conversion of the surplus-product of A, A', etc. (I), into money. Aside from this, where does the money come from? We know that B, B', B'', etc. (I) have formed their hoard in the same way as A, A', etc., by the sale of their respective surplus-products. Now they have arrived at the point where their hoarded, only virtual, money-capital is to function effectively as additional money-capital. But this is merely going round in circles. The question still remains: Where does the money come from which the B's (I) before withdrew from circulation and accumulated? We know from the analysis of simple reproduction that capitalists I and II must have a certain amount of money at hand in order to be able to exchange their surplus-product. In that case the money which served only as revenue to be spent for articles of consumption returned to the capitalists in the same measure in which they had advanced it for the exchange of their respective commodities. Here the same money re-appears, but performing a different function. The A's and B's (I) supply one another alternately with the money for converting surplus-product into additional virtual money-capital, and throw the newly formed money-capital alternately back into circulation as a means of purchase. The only assumption made in this case is that the amount of money in the country in question (the velocity of circulation, etc., being constant) should suffice for both the active circulation and the reserve hoard. As we have seen this is the same assumption as had to be made in the case of the simple circulation of commodities. Only the function of the hoards is different in the present case. Furthermore, the available amount of money must be larger, first, because under capitalist production all the products (with the exception of newly produced precious metals and the few products consumed by the producer himself) are created as commodities and must therefore pass through the pupation stage of money; secondly, because on a capitalist basis the quantity of the commodity-capital and the magnitude of its value is not only absolutely greater but also grows with incomparably greater rapidity; thirdly, because an ever expanding variable capital must always be converted into money-capital; fourthly, because the formation of new money-capitals keeps pace with the extension of production, so that the material for corresponding hoard formation must be available.