A System of Mechanical Philosophy, Volume 1

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J. Murray, 1822 - 50 pages

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Page 556 - This we have followed, because, " in the middle parts of Europe we have no cogent reason for deviating from it ; " and if any architect should deviate greatly in a building where the outline is " exhibited as beautiful, we should be disgusted ; but the disgust, though felt " by almost every spectator, has its origin in nothing but habit. In the professed architect or man of education, the disgust arises from pedantry; for " there is not such a close connection between the form and uses of a roof...
Page 555 - ... pitched roofs; and their pitch will always be nearly such as suits the climate and covering. Our architects, however, go to work on different principles. Their professed aim is to make a beautiful object. The sources of the pleasures arising from what we call taste are so various, so complicated, and even so whimsical, that it is almost in vain to look for principle in the rules adopted by our professed architects.
Page 609 - Two models were made 18 inches ^square ; one consisted of .single joists, the other framed with girders, binding, bridging, and ceiling joists; the single joists of the one contained the same quantity of timber with the girders alone of the other. They were placed in a wooden trunk 18 inches square within, with a strong projection on the inside for the floors to rest on, and small shot was gradually poured over. The single joisted floor broke down with 487 pounds ; the framed floor, with 32 7 pounds.
Page 403 - According to Mr. Emerson, the load which may be safely suspended to an inch square, is as follows : Iron 76,400 Brass 35,600 Hempen rope ... 19,600 Ivory 15,700 Oak, box, yew, plumtree 7,850 Elm, ash, beech - - - 6,070 Walnut, plum - - - - 5,360 Red fir, holly, elder, plane, crab - - - - 5,000 Cherry...
Page 408 - He observes, also, that it requires something more than sixty pounds on every square line, to crush a piece of sound oak ; but this rule is by no means general, glass, for instance, will carry a hundred times more on it than oak in this way, but will not bear suspended above four or five times as much. Oak will suspend a great deal more than fir, but fir, as a pillar, will carry twice as much.
Page 612 - When carried so much higher that the distance of the ribs is one third of the original distance, every second rib, now consisting of two ribs very near each other, is in like manner discontinued, and the void is glazed. A little above this the heads of the ribs are framed into a circular ring of timber, which forms a wide opening in the middle ; over which is a glazed canopy or umbrella, with an opening between it and the dome for allowing the heated air to get out. All who have seen this dome say...
Page 251 - ... inch. For we must not conclude that they are in contact till the black spot appears ; and even then we dare not positively affirm it. My own decided opinion is, that the glasses not only are not in mathematical contact in the black spot, but the distance between them, is vastly greater than the 89,000th part of an inch, the difference of -the distances at two successive rings.
Page 577 - KAH, LBM. Moreover, let G be the centre of gravity of the beam, and let GN be a line through the centre of gravity, perpendicular to the horizon. The beam will not be in equilibrio unless the vertical line GN either passes through P, the point in which the directions of the two lines AC, BD, or the directions of the two props EA, FD, or the perpendiculars to the two planes KAH, LBM, intersect each other, or is parallel to these directions. For the supports given by the lines or props are unquestionably...
Page 612 - Moulineau'a principles, and astonished that a thing so plain had not been long familiar to every house-carpenter. It quickly became an universal topic of conversation, dispute, and cabal, in the polite circles of Paris. But the Academy having given a very favourable report of their opinion, the project was immediately carried into execution, and soon completed ; and now stands as one of the great exhibitions of Paris. The construction of this dome is the simplest thing that can be imagined. The circular...
Page 536 - Perronet, however, fearing that the great length of the bolts employed to connect the beams of these stretchers would expose them to the risk of bending, scarfed the two side pieces into the middle piece. The scarfing was of the triangular kind, called " Trait do Jupiter " (which will be described in connection with Fig. 98), each

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