_Displacements of Mature Laborers naturally tending to Diminish._--When an improvement is made in one of the upper subgroups while the general flow of labor is toward these groups, the effect is not usually to lessen the absolute number of workers in the upper subgroup where the improvement has been made, but merely to prevent it from getting a _pro rata_ share of the labor that is moving upward toward this tier of subgroups from the lower ones. The change in the apportionment of the social laboring force between the upper subgroups and the lower ones is made gradually, without violent transfers of particular men from point to point, and merely by directing to the upper subgroups a disproportionate number of young workers who are selecting their fields of employment. In general, _labor_ moves from point to point in the system without requiring many _particular laborers_ to do so. As actual loss of places by persons of mature age is the chief evil connected with changes in methods of production, it is a most welcome fact that the influence which we are studying tends naturally to reduce the extent of it. _The Discarding of Aged Laborers mainly caused by a Further Influence._--Quite apart from a demand for less labor at a particular point in the system, there may occur a discharging of men merely because of age and a substituting of younger men. In establishments where the pace is a rapid one men have thus to give place to young successors at an earlier age than the one at which men give place in other employments. The effect of some machinery is to improve the chances of old men, while that of other machinery is to reduce them. A lightening of toil and a shortening of the working day preserve men's powers and enable them to retain employment longer.