growth of output due solely to increase in technical progress. Meade denotes these four proportionate rates of growth as and respectively. is the proportion of net national income to be paid in net profits (provided the owners of machinery receive a reward equal to the value of the net marginal product of the machinery). Meade denotes this as and calls it "the proportional marginal product of machinery". Under the assumption of constant returns to scale, it is equal to the proportion of national income received in profits. Similarly, represents the proportional marginal product of labour and is equal to the proportion of the net national income going to wages under conditions of constant-returns competitive equilibrium. Meade denotes this as . Hence equation 1 can be written as (Equation 2) This shows the growth rate of output as being the weighted sum of three other growth rates, the sum of the growth rate in the stock of machines weighted by the marginal importance of machinery in the production process i.e., in a competitive equilibrium by the proportion of the national income going to profits plus the growth rate of the population weighted by the marginal importance of labour in the production process or, in a competitive equilibrium by the proportion of income going to wages plus the growth rate of technical progress Hence equation 2 can be written as (Equation 3) Since is the difference between the growth rate of total output and the growth rate of the workforce, the growth rate of the real income per head can be measured. For example, if the total real income is increasing by 10 percent every annum but the working population is growing at 8 percent per annum, the income per head is rising by approximately 2 percent per annum. Equation 3 shows that the growth rate of real income per head (y – l) is the output of three factors. Firstly it is raised by the growth rate in real capital weighted by its proportional marginal product or by the proportion of net national income which would be paid min profits in a competitive equilibrium . Secondly, it is depressed by the growth rate in the working population weighted by one minus the proportional marginal product of labour . Lastly, it is raised by the amount of technology in the economy . The element in equation 3 can also be written down