38 ECONOMIC ESSAYS IN HONOR OF JOHN BATES CLARK everybody upward in the scale of occupations, then no occupation or class of occupations can possibly be congested. This does not assume, of course, that low mentality can ever be trained sufficiently for the highest intellectual occupations. It merely means that men in every grade of natural mentality may be so trained as to fit them for slightly higher occupations than they would be fitted for without education or training. Even a moderate efficiency in an educational system would produce pro- found changes of this kind, that is, it would thin out the numbers that were compelled to follow the lowest grade of occupations and increase the numbers that were available for the highest or most highly paid occupations. This may be illustrated by the following hypothetical table. DISTRIBUTION OF WORKING PoPULATION AMONG INDUSTRIAL GROUPS Resulting Distribu- tion of Workers in a Country with Popu- lar Education Per Cent Q A B C D E 16 32 40 100 17 21 36 20 100 Even though hypothetical it is sufficient to illustrate the principle. In this table we shall grade the occupations into five groups according to the degree of mentality required in each.” In group A we shall include the highest grade of occupations, that is, those in which properly qualified men are scarce and highly paid. In Group E we shall include the lowest,—those in which properly qualified men are most abundant and most poorly paid. The other groups are arranged between these two extremes. Let as assume that, in the absence of a system of popular education, only 4 per cent of the working population would be fitted for the occupations in Group A, 8 per cent for Group B, 16 per cent for Group C, 32 per cent for Group D, and 40 per cent for Group E. This inequality in the occupational distribution of the population would normally produce a wide inequality in the incomes of the different groups. Those in Group A would normally receive : ae Carver and Hall, Human Relations. D. C. Heath & Co., 1923, D.