ONE:Let the reader compare a hammer with a wheel and axle, inclined plane, screw, or lever, as an agent for concentrating and applying power, noting the principles of its action first, and then considering its universal use, and he will conclude that, if there is a mechanical device that comprehends distinct principles, that device is the common hammer. It seems, indeed, to be one of those provisions to meet a human necessity, and without which mechanical industry could not be carried on. In the manipulation of nearly every kind of material, the hammer is continually necessary in order to exert a force beyond what the hands may do, unaided by mechanism to multiply their force. A carpenter in driving a spike requires a force of from one to two tons; a blacksmith requires a force of from five pounds to five tons to meet the requirements of his work; a stonemason applies a force of from one hundred to one thousand pounds in driving the edge of his tools; chipping, calking, in fact nearly all mechanical operations, consist more or less in blows, such blows being the application of accumulated force expended throughout a limited distance.One of the problems connected with the handling of material is to determine where hand-power should stop and motive-power begin��what conditions will justify the erection of cranes, hoists, or tramways, and what conditions will not. Frequent mistakes are made in the application of power when it is not required, especially for handling material; the too common tendency of the present day being to apply power to every purpose where it is possible, without estimating the actual saving that, may be effected. A common impression is that motive power, wherever applied to supplant hand labour in handling material, produces a gain; but in many cases the [66] fallacy of this will be apparent, when all the conditions are taken into account.
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ONE:"But how did you know that I had it?"
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ONE:"You know very well where your brother is," Leona replied. "He is dead. He died in a house that is very close to here."To follow the same chain of reasoning still farther, and to show what may be gained by method and system in learning mechanics, it may be assumed that machine functions consist in the application of power, and therefore power should be first studied; of this there can be but one opinion. The learner who sets out to master even the elementary principles of mechanics without first having formed a true conception of power as an element, is in a measure wasting his time and squandering his efforts.
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ONE:The next great forward step in speculation was taken by Anaximander, another Milesian, also of distinguished attainments in mathematics and astronomy. We have seen that to Thales water, the all-embracing element, became, as such, the first cause of all things, the absolute principle of existence. His successor adopted the same general point of view, but looked out from it with a more penetrating gaze. Beyond water lay something else which he called the Infinite. He did not mean the empty abstraction which has stalked about in modern times under that ill-omened name, nor yet did he mean infinite space, but something richer and more concrete than either; a storehouse of materials whence the waste of existence could be perpetually made good. The growth and decay of individual forms involve a ceaseless drain on Nature, and the deficiency must be supplied by a corresponding influx from without.A For, be it observed that, although the Greek thinkers were at this period well aware that nothing can come from nothing, they had not yet grasped the complementary truth inalienably wedded to it by Lucretius in one immortal couplet, that nothing can return to nothing; and Kant is quite mistaken when he treats the two as historically inseparable. Common experience forces the one on our attention much sooner than the other. Our incomings are very strictly measured out and accounted for without difficulty, while it is hard to tell what becomes of all our expenditure, physical and economical. Yet, although the indestructibility of matter was a conception which had not yet dawned on Anaximander, he seems to have been feeling his way towards the recognition of a circulatory movement pervading all Nature. Everything, he says, must at last be reabsorbed in the Infinite as a punishment for the sin of its separate existence.10 Some may find in this sentiment a note of Oriental10 mysticism. Rather does its very sadness illustrate the healthy vitality of Greek feeling, to which absorption seemed like the punishment of a crime against the absolute, and not, as to so many Asiatics, the crown and consummation of spiritual perfection. Be this as it may, a doctrine which identified the death of the whole world with its reabsorption into a higher reality would soon suggest the idea that its component parts vanish only to reappear in new combinations.
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ONE:The adaptation, endurance, and cost of machines in designing become resolved into problems of movements, the arrangement of parts, and proportions.
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