A Man's Work.

Bruce Herald, Volume IX, Issue 801, 9 May 1876, Page 7

A Man's Work.

How best to utilise human labor, and at the same time to produce the least fatigue, is one of those interesting problems in industrial mechanics which every inventor of machines based on man-power as a motor is called upon to consider, and to which every employer of men for the sake of their brute muscular strength is obliged to give some attention. It is a common error to believe that, in order to produce a given amount of work, a mail always expends a given .amount of power, and to recognise this as the first Btep towards a correct estimation of a man's muscular capability. Appropriate rests are absolute necessities to the human machine, and it is by intermittent, nob continuous, efforts that its best work ia produced. One man laboring ten hours and taking intervals of repose will produce more force and accomplish more work with less fatigue than another laboring eight hours with shorter or less frequent rests, the actual time spent in working in both cases being equal. But on the other hand, during the periods of absolute work regularity i 3 a necessity, a fact clearly shown by the government of soldiers on long marches, where the drum to which the feet keep time is a wonderful agent for repressing fatigue, simply because it ensures regularity of motion. So also in rowing in a long raGe experience has proved the advantage of a clockwork regularity of stroke with a brief breathing spell between each pull. In fact »••• appears that men will naturally fall into this cadence, as witness the blows delivered by laborers with sledge hammers upon rock drills, and the peculia? timed "hup " which each will aspirate as his implement falls, or the tendency which sailors have to break into a cadenced singsong when pulling a standing haul on a rope. A more curious iilflt»ace in thia Baaie regard^js found, in the

power of dancing ; nothing but the repeated rests and the regular movements will explain the ability of women, to whom ordinarily a walk of a mile in length is a severe task, to dance during a period of .five or six hours, aud this at a time when Nature is most exhausted, owing to. deprivation of sleep. The best application a man can make of his power is through his legs, for the muscles of those members are not only absolutely but relatively stronger than those of the arms. In other words, after work the fatigue produced in both sots of muscles beiug equal, the leg muscles will have performed more useful labor than those of the arms. And further, the nearer we imitate a natural movement the better do we apply the power, therefore a walking motion of the legs, at a velocity equal to that of an ordinary gait, and applied to levers, is probably the most efficacious application of human force for steady work. As to the absolute power of a man, expressed in pounds to be lifted or in similar terms, exact data are obviously impossible, even for an average individual. An interesting series of experiments were conducted on this Bubject some time ago in France, and these, we believe, give a fair approximation. The heaviest load a man of strength can carry for a short distance is placed at 319 pounds. All a man can carry habitually — as a soldier his knapsack — walking on level ground is 132 pounds, and this is an extreme load, we should judge. Or he can carry an aggregate of 1518 pounds over 3200 feet as a day's work under like circumstances. If he ascend ladders or stairs— as do hod-carriers— then he can carry but 121 pounds continuously, and his day's work cannot exceed 1232 pounds raised 3200 feet high. With regard to the effort and the velocity which a man can produce by pulling or pushing with hia arms, it has been found that, under the most favorable circumstances and for continuous work, an effect exceeding from 20 4 to 33 pounds raised from 18 to 2 1 feet per second cannot be gained, and this is equal to about power. — ' Scientific American.'