There is no theory, no a priori rule, by which the respective attractiveness of industries is determined.

The administration, in taking burdens off one class of workers and adding them to other classes, simply follows the fluctuations of opinion among the workers themselves as indicated by the rate of volunteering.

The principle is that no man's work ought to be, on the whole, harder for him than any other man's for him, the workers themselves to be the judges.

There are no limits to the application of this rule.

If any particular occupation is in itself so arduous or so oppressive that, in order to induce volunteers, the day's work in it had to be reduced to ten minutes, it would be done.