Natural Philosophy ...

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Potter, 1874 - Physics - 405 pages
 

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Page 34 - ... that it is the pressure of the atmosphere on the surface of the water in the dish which keeps the water in the inverted jar.
Page 355 - Through the high wood echoing shrill; Sometime walking, not unseen, By hedge-row elms, on hillocks green, Right against the eastern gate Where the great Sun begins his state Robed in flames and amber light, The clouds in thousand liveries dight...
Page 27 - ... tube. The lower end of the rod rests upon the sound-board of the piano, its upper end being exposed before you. An artist is at this moment engaged at the instrument, but you hear no sound. I place this violin upon the end of the rod; the violin becomes instantly musical, not however with the vibrations of its own strings, but with those of the piano.
Page 373 - Her ivory forehead full of bounty brave, Like a broad table did itself dispread, For Love his lofty triumphs to engrave, ' And write the battles of his great godhead : All good and honour might therein be read; For there their dwelling was.
Page 24 - This result gives the weight of a bulk of water equal to that of the specimen, and by dividing the weight of the specimen in air by this number, the specific gravity is obtained.
Page 175 - Mirrors. — Any smooth reflecting surface is called a mirror. If the surface is flat, it is called a plane mirror. In Figure 136 suppose a point of light A to be in front of the plane mirror N M. The rays diverging from A, as AB and AC are reflected from the mirror so as to make the angle of reflection equal to that of incidence. After reflection they enter the eye O just as if they came from the point a. This point will therefore appear to be just as far behind the mirror as A is in front of it....
Page 37 - A little reflection will make it plain, that in the interval required by the one fork to execute one vibration more than the other, a beat must occur ; and inasmuch as, in the case now before us, there are six such intervals in a second, there must be six beats in the same time. In short, the number of beats per second is always equal to the difference between the two rates of vibration.
Page 363 - Making allowance for the heat absorbed by the atmosphere, it has been calculated that the amount received by the earth during a year would be sufficient to melt a layer of ice 100 feet thick and covering the whole earth. But the sun radiates heat into space in every other direction as well as towards the earth; and if we conceive a hollow sphere to surround the sun at the distance of the earth, our planet would cover only of its surface.
Page 62 - There are various ways of agitating the air at the ends of pipes and tubes, so as to throw the columns within them into vibration. In organ-pipes this is done by blowing a thin sheet of air against a sharp edge. This produces a flutter, some particular pulse of which is then converted into a musical sound by the resonance of the associated column of air.
Page 367 - ... seems to be secured, so that for ourselves and for long generations after us we have nothing to fear. But the same forces of air and water, and of the volcanic interior, which produced former geological revolutions, and buried one series of living forms after another, act still upon the earth's crust. They more probably will bring about the last day of the human race than those distant cosmical alterations of which we have spoken...

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