If the productivity of industry increases, the price of individual
 commodities falls. There is less labour in them, less paid and unpaid labour.
 Suppose, the same labour produces, say, triple its former product. Then
 ⅔ less labour yields individual product. And since profit can make up
 but a portion of the amount of labour contained in an individual commodity, the
 mass of profit in the individual commodity must decrease, and this takes place
 within certain limits, even if the rate of surplus-value should rise. In any
 case, the mass of profit on the total product does not fall below the original
 mass of profit so long as the capital employs the same number of labourers at
 the same degree of exploitation. (This may also occur if fewer labourers are
 employed at a higher rate of exploitation.) For the mass of profit on the
 individual product decreases proportionately to the increase in the number of
 products. The mass of profit remains the same, but it is distributed
 differently over the total amount of commodities. Nor does this alter the
 distribution between the labourers and capitalists of the amount of value
 created by newly added labour. The mass of profit cannot increase so long as
 the same amount of labour is employed, unless the unpaid surplus-labour
 increases, or, should intensity of exploitation remain the same, unless the
 number of labourers grows. Or, both these causes may combine to produce this
 result. In all these cases — which, however, in accordance with our
 assumption, presuppose an increase of constant capital as compared to variable,
 and an increase in the magnitude of total capital — the individual
 commodity contains a smaller mass of profit and the rate of profit falls even
 if calculated on the individual commodity. A given quantity of newly added
 labour materialises in a larger quantity of commodities. The price of the
 individual commodity falls. Considered abstractly the rate of profit may remain
 the same, even though the price of the individual commodity may fall as a
 result of greater productiveness of labour and a simultaneous increase in the
 number of this cheaper commodity if, for instance, the increase in
 productiveness of labour acts uniformly and simultaneously on all the elements
 of the commodity, so that its total price falls in the same proportion in which
 the productivity of labour increases, while, on the other hand, the mutual
 relation of the different elements of the price of the commodity remains the
 same. The rate of profit could even rise if a rise in the rate of surplus-value
 were accompanied by a substantial reduction in the value of the elements of
 constant, and particularly of fixed, capital.