It is, however, worth pointing out that, of the four terms ed, ew, ee and eo upon which the effect on prices of changes in the quantity of money depends, ed stands for the liquidity factors which determine the demand for money in each situation, ew for the labour factors (or, more strictly, the factors entering into prime cost) which determine the extent to which money wages are raised as employment increases, and ee and eo for the physical factors which determine the rate of decreasing returns as more employment is applied to the existing equipment.