The Theory of Sound, المجلد 2

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الصفحات المحددة

طبعات أخرى - عرض جميع المقتطفات

عبارات ومصطلحات مألوفة

مقاطع مشهورة

الصفحة 5 - so that by differentiating the first of the above equations with respect to y and the second with respect to x, and subtracting...
الصفحة 370 - Under moderate electrical influence there is no material change in the resolution into drops, nor in the subsequent motion of the drops up to the moment of collision. The difference begins here. Instead of rebounding after collision, as the unelectrified drops of clean water generally or always do, the electrified drops coalesce, and thus the jet is no longer scattered about. When the electrical influence...
الصفحة 471 - U, etc., so that it would appear as if in simple sounds, that each vowel was inseparable from a peculiar pitch, and that in the compound system of pulses, although its pitch be lost, its vowel quality is strengthened." . . . "Having shown the probability that a given vowel is merely the rapid repetition of its peculiar note...
الصفحة 240 - ... becomes posterior. If the rate of alternation o'f the body's motion be taken greater and greater, or, in other words, the periodic time less and less, the condensation and rarefaction of the gas, which in the first instance was utterly insensible, presently becomes sensible, and...
الصفحة 411 - The second plate may conveniently be made triangular, the turned down corners being soldered to the first plate. For calls of medium pitch the holes may be made in tin plate. They may be as small as ^ mm. in diameter, and the distance between them as little as 1 mm. In any case the edges of the holes should be sharp and clean.
الصفحة 33 - In a stationary wave-form a loss of velocity accompanies an augmented density according to the principle of energy, and therefore the fluid composing the condensed parts of a wave moves forward more slowly than the undisturbed portions. Relatively to the fluid...
الصفحة 402 - A jet of coal gas from a pin-hole burner rises vertically in the interior of a cavity from which the air is excluded. It then passes into a brass tube a few inches long, and on reaching the top, burns in the open. The front wall of the cavity is formed of a flexible membrane of tissue paper, through which external sounds can reach the burner.
الصفحة 36 - Thus the motion, as determined by Poisson's integral, becomes discontinuous after a time equal to the reciprocal, taken positively, of the greatest negative value of du/dx. For example, let us suppose that u = U cos — {x-(a+u)t}, (4) At where U is the greatest initial velocity.
الصفحة 351 - Thomson has shown, the force governing the vibrations is principally cohesion. On the down-stream side the waves are longer and are governed principally by gravity. Both sets of waves move with the same velocity relatively to the water, namely, that required in order that they may maintain a fixed position relatively to the obstacle. The same condition governs the velocity, and therefore the wavelength, of those parts of the wave-pattern where the fronts are oblique to the direction of motion.
الصفحة 434 - Now it is evident that a superior limit to the amplitude of waves giving an audible sound may be arrived at from a knowledge of the energy which must be expended in a given time in order to generate them, and of the extent of surface over which the waves so generated are spread at the time of hearing. An estimate founded on these data will necessarily be too high, both because sound-waves must suffer some dissipation in their progress, and also because a part, and in some cases a large part, of the...

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