A large amount of very valuable data had been obtained, which enabled us to know, for many kinds of labor, what was a proper day's work.It did not seem wise, however, at this time to spend any more money in trying to find the exact law which we were after.Some years later, when more money was available for this purpose, a second series of experiments was made, similar to the first, but somewhat more thorough.This, however, resulted as the first experiments, in obtaining valuable information but not in the development of a law.Again, some years later, a third series of experiments was made, and this time no trouble was spared in our endeavor to make the work thorough.Every minute element which could in anyway affect the problem was carefully noted and studied, and two college men devoted about three months to the experiments.After this data was again translated into foot-pounds of energy exerted for each man each day, it became perfectly clear that there is no direct relation between the horse-power which a man exerts(that is, his foot-pounds of energy per day) and the tiring effect of the work on the man.The writer, however, was quite as firmly convinced as ever that some definite, clear-cut law existed as to what constitutes a full day's work for a first-class laborer, and our data had been so carefully collected and recorded that he felt sure that the necessary information was included somewhere in the records.The problem of developing this law from the accumulated facts was therefore handed over to Mr Carl G.Barth, who is a better mathematician than any of the rest of us, and we decided to investigate the problem in a new way, by graphically representing each element of the work through plotting curves, which should give us, as it were, a bird's-eye view of every element.In a comparatively short time Mr Barth had discovered the law governing the tiring effect of heavy labor on a first-class man.And it is so simple in its nature that it is truly remarkable that it should not have been discovered and clearly understood years before.The law which was developed is as follows:
The law is confined to that class of work in which the limit of a man's capacity is reached because he is tired out.It is the law of heavy laboring, corresponding to the work of the cart horse, rather than that of the trotter.Practically all such work consists of a heavy pull or a push on the man's arms, that is, the man's strength is exerted by either lifting or pushing something which he grasps in his hands.And the law is that for each given pull or push on the man's arms it is possible for the workman to be under load for only a definite percentage of the day.For example, when pig iron is being handled (each pig weighing 92 pounds), a first-class workman can only be under load 43 per cent of the day.He must be entirely free from load during 57 per cent of the day.And as the load becomes lighter, the percentage of the day under which the man can remain under load increases.So that, if the workman is handling a half-pig, weighing 46 pounds, he can then be under load 58 per cent of the day, and only has to rest during 42 per cent.As the weight grows lighter the man can remain under load during a larger and larger percentage of the day, until finally a load is reached which he can carry in his hands all day long without being tired out.When that point has been arrived at this law ceases to be useful as a guide to a laborer's endurance, and some other law must be found which indicates the man's capacity for work.
When a laborer is carrying a piece of pig iron weighing 92 pounds in his hands, it tires him about as much to stand still under the load as it does to walk with it, since his arm muscles are under the same severe tension whether he is moving or not.A man, however, who stands still under a load is exerting no horse-power whatever, and this accounts for the fact that no constant relation could be traced in various kinds of heavy laboring work between the foot-pounds of energy exerted and the tiring effect of the work on the man.It will also be clear that in all work of this kind it is necessary for the arms of the workman to be completely free from load (that is, for the workman to rest) at frequent intervals.Throughout the time that the man is under a heavy load the tissues of his arm muscles are in process of degeneration, and frequent periods of rest are required in order that the blood may have a chance to restore these tissues to their normal condition.
To return now to our pig-iron handlers at the Bethlehem Steel Company.If Schmidt had been allowed to attack the pile of 47 tons of pig iron without the guidance or direction of a man who understood the art, or science, of handling pig iron, in his desire to earn his high wages he would probably have tired himself out by 11 or 12 o'clock in the day.He would have kept so steadily at work that his muscles would not have had the proper periods of rest absolutely needed for recuperation, and he would have been completely exhausted early in the day.By having a man, however, who understood this law, stand over him and direct his work, day after day, until he acquired the habit of resting at proper intervals, he was able to work at an even gait all day long without unduly tiring himself.
Now one of the very first requirements for a man who is fit to handle pig iron as a regular occupation is that he shall be so stupid and so phlegmatic that he more nearly resembles in his mental make-up the ox than any other type.The man who is mentally alert and intelligent is for this very reason entirely unsuited to what would, for him, be the grinding monotony of work of this character.Therefore the workman who is best suited to handling pig iron is unable to understand the real science of doing this class of work.He is so stupid that the word "percentage" has no meaning to him, and he must consequently be trained by a man more intelligent than himself into the habit of working in accordance with the laws of this science before he can be successful.
