Still another quality necessary in the successful manager, is the ability to judge men and their capacities for various duties. To get always the right man for the position, the machine, or the job, is a valuable trait in any man who is to direct the work of even a moderate─sized establishment. The larger the plant and the more diversified the business carried on in it, the more valuable and indispensable this characteristic will become. The manager who is continually or frequently changing his subordinate officials, and consequently producing changes in the working force, will always find his duties arduous, and will also find it well─nigh impossible to get the plant up to the degree of efficiency that is to be reasonably expected. The volume of output will continually fall below the normal point, and the quality of the work will also deteriorate. The work of management should be a constant upbuilding of the force, and of development and education along the lines of advancement in the special output of the concern. This cannot be carried on if the composition of the force, or the officials who handle it, are in a transition state of change, doubt, and uncertainty. [Illustration: SHOWING USE OF PIT LATHE IN MACHINING A CENTER OF SWING BRIDGE Chicago Bridge & Iron Works, Chicago, Ill.] There is, on the part of many officials having charge of men, a propensity to interfere too much with workmen and their work, and thus to hinder rather than help them. While it is quite true that every official from the Gang Boss up to the Factory Manager can, at various times, help the workmen in their allotted tasks by timely advice and suggestions, it is also true that this is a matter that can be easily overdone, until it becomes an annoying nuisance and unnecessarily interferes with the men in the discharge of their legitimate duties. Workmen are quick to discern when suggestions and advice are well meant and instructive, and when they come as a kind of veiled criticism. The official who permits himself to indulge in this sort of dictation soon falls into a practice of _nagging_ that is most exasperating to the men. It is a practice that first weakens and then destroys the official's influence with the men, who obey only from necessity. When this condition exists, the working efficiency of the force is at a very low ebb. On the other hand, really helpful advice and suggestions, made in a cheerful manner and from a quite apparent desire to assist workmen, will usually meet with a quick and loyal response that argues well for the efficiency of the workmen.