TWO:Judged upon theoretical grounds, and leaving out the mechanical conditions of operation, it would at once be conceded that a proper plan would be to move the lightest body; that is, if the tools and their attachments were heavier than the material to be acted upon, then the material should be moved for the cutting action, and vice versa. But in practice there are other conditions to be considered more important than a question of the relative weight of reciprocating parts; and it must be remembered that in solving any problem pertaining to machine action, the conditions of operation are to be considered first and have precedence over problems of strain, arrangement, or even the general principles of construction; that is, the conditions of operating must form a base from which proportions, arrangements, and so on, must be deduced. A standard planing machine, such as is employed for most kinds of work, is arranged with a running platen or carriage upon which the material is fastened and traversed beneath the cutting tools. [130] The uniformity of arrangement and design in machines of this kind in all countries wherever they are made, must lead to the conclusion that there are substantial reasons for employing running platens instead of giving a cutting movement to the tools.Geometrical drawing is not an artistic art so much as it is a constructive mechanical one; displaying the parts of machinery on paper, is much the same in practice, and just the same in principle, as measuring and laying out work in the shop. More info

TWO:"I fancy I can see a way out of the difficulty," he said. "I do not wish to pry into your affairs, but in a novelist's business one gets to know things. And I, too, am in a great quandary. Do you recollect the flower farm near Ajaccio?"Facing them was a wide opening, sufficiently spacious to permit airplanes to be rolled through: in grooved slots at either side the door, made of joined metal slats working like the old-fashioned roll-top desk, could be raised or lowered by a motor and cable led over a drum. More info

TWO:Nor is this all. After sharply distinguishing what is from what is not, and refusing to admit any intermediary between them, Aristotle proceeds to discover such an intermediary in the shape of what he calls Accidental Predication.236 An accident is an attribute not necessarily or usually inhering in its subject��in other words, a co-existence not dependent on causation. Aristotle could never distinguish between the two notions of cause and kind, nor yet between interferences with the action of some particular cause and exceptions to the law of causation in general; and so he could not frame an intelligible theory of chance. Some propositions, he tells us, are necessarily true, others are only generally true; and it is the exceptions to the latter which constitute accident; as, for instance, when a cold day happens to come in the middle341 of summer. So also a man is necessarily an animal, but only exceptionally white. Such distinctions are not uninteresting, for they prove with what difficulties the idea of invariable sequence had to contend before even the highest intellects could grasp it. There was a constant liability to confound the order of succession with the order of co-existence, the order of our sensations with the order of objective existence, and the subjection of human actions to any fixed order, with the impossibility of deliberation and choice. The earlier Greek thinkers had proclaimed that all things existed by necessity; but with their purely geometrical or historical point of view, they entirely ignored the more complex questions raised by theories about classification, logical attribution, and moral responsibility. And the modifications introduced by Epicurus, into the old physics, show us how unanswerable Aristotle��s reasonings seemed to some of his ablest successors. More info