Waves and Ripples in Water, Air, and Ęther: Being a Course of Christmas Lectures Delivered at the Royal Institution of Great Britain

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Society for promoting Christian knowledge, 1902 - Electric waves - 299 pages
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Page 10 - A formal and exact proof of the law connecting speed and wave-length for deep-sea waves requires mathematical reasoning of an advanced character ; but its results may be expressed in a very simple statement, by saying that, in the case of waves...
Page 199 - In the same way, if we place some mercury or water in a glass tube bent in the shape of the letter U...
Page 144 - Then nearly fill up the bottle with Price's glycerine,- and shake well. Leave the bottle stoppered for a week in a dark place.
Page 164 - ... put them out of tune. When this is done you can no longer hear the smooth sound, but a sort of waxing and waning in the sound, and this alternate increase and diminution in loudness is called a beat. We can easily take count of the number of beats per second, and by the reasoning given above we see that the number of beats per second must be equal to the difference between the frequencies of the two sets of waves. Thus if one organpipe is giving 100 vibrations per second to the air, and the other...
Page 165 - It has already been explained that when a string vibrates it does so not only as a whole, but also in sections, giving out a fundamental note with superposed harmonics.
Page 68 - ... have not been instructed in the subject, perhaps even now have the idea that this so-called "head resistance" is the chief cause of the resistance experienced when we make a body of any shape move through water. A common assumption is also that the object of making a ship's bows sharp is that they may cut into the water like a wedge, and more easily push it out of the way. Scientific investigation has, however, shown that both of these notions are erroneous. The resistance felt in pulling or...
Page 9 - This relation, which we shall have frequent occasion to recall, may be stated in another manner. We call the period of a wave the time taken to make one complete movement.
Page 20 - This rather difficult, but important, idea of the distinction between the velocity of a group of waves and that of...
Page 183 - ... amazing dance of molecules to and fro and from side to side, as the medley of waves of compression or rarefaction embraced them and drove them hither and thither in their resistless grasp. The tympana of our ears are therefore undergoing motions of a like complicated kind, and this complex movement is transmitted through the chain of bones in the middle ear to the inner ear, or true organ of sensation. But there, by some wondrous mechanism not at all yet fully understood, an analysis takes place...
Page 112 - ... next outer layer of air and rarefies itself. Then, again, the second layer in expanding compresses a third, and so on. Accordingly, a state of compression is handed on from layer to layer, and each state of compression is followed by one of rarefaction. The individual air-particles are caused to move to and fro in the direction of the radii of the sphere of which the source of explosion is the centre. Hence we have what is called a spherical longitudinal wave produced. Each air-particle swings...

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