Karl Marx: The mass of surplus-value produced by a capital of a given magnitude is the product of two factors — the rate of surplus-value multiplied by the number of labourers employed at this rate. At a given rate of surplus-value it therefore depends on the number of labourers, and it depends on the rate of surplus-value when the number of labourers is given. Generally, therefore, it depends on the composite ratio of the absolute magnitudes of the variable capital and the rate of surplus-value. Now we have seen that, on the average, the same factors which raise the rate of relative surplus-value lower the mass of the employed labour-power. It is evident, however, that this will occur to a greater or lesser extent, depending on the definite proportion in which this conflicting movement obtains, and that the tendency towards a reduction in the rate of profit is notably weakened by a rise in the rate of absolute surplus-value, which originates with the lengthening of the working-day. https://wordsmith.social/protestation/quotes#quote9255