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aberration absolute pitch amplitude angle aperture applicable approximately axis calculated centimetre circuit coefficient colour condensation considerable considered constant corresponding cylinder denote density depends determined diameter difference direction displacement distance disturbance double refraction effect electrical electromotive force equal equation equilibrium experiments expression fluid force fork formula frequency function galvanometer given glass grating Grove cell heat inch increase infinite integration intensity investigation kinetic energy length lens light limit lines motion necks obliquity observed obtained optical orifice paper parallel particles period perpendicular phase Phil pipe pitch plane plane waves plate polarization position potential energy pressure principal prisms proportional quantity quarter period radius ratio rays reflection refraction refractive index resistance resolving-power resonator result rotation self-induction solution sound spectrum stream sufficient suppose surface theorem theory thickness tube vanishes velocity velocity of propagation vibrations vis viva wave-length waves wire zero
Page 336 - lose one complete vibration as compared with the pendulum. Whether the difference is a loss or a gain is easily determined in any particular case by observing whether the apparent motion of the spot across the slit (which should have a visible breadth) is in the same or in the opposite direction to that of the pendulum's motion.
Page 92 - b, the velocity of propagation of light; D and D', the original and altered densities: of which the first three depend only on space, the fourth on space and time, while the fifth and sixth introduce the consideration of mass. Other elements of the problem there are none, except mere numbers and angles, which do not depend
Page 532 - so that the intensity is proportional to the square of the sine of the angle between the secondary ray and the direction of the primary electrical displacement. The blue colour of the light scattered from small particles is explained by the occurrence of
Page 430 - as that incurred without a change of refrangibility when we pass from the principal direction to that corresponding to the first minimum of illumination. That the resolving-power of a prismatic spectroscope of given dispersive material is proportional to the total thickness used, without regard to the number, angles, or setting of the prisms, is a most
Page 429 - be a plane wave-surface of the light before it falls upon the prisms, AB the corresponding wave-surface for a particular part of the spectrum after the light has passed the prism or after it has passed the eyepiece of the observing-telescope. The path of a ray from the wave-surface A 0 B 0 to A
Page 519 - The function of a lens in forming an image is to compensate by its variable thickness the differences in phase which would otherwise exist between secondary waves arriving at the focal point from various parts of the aperture. If we suppose the diameter of the lens (2r) to be given, and its focal length
Page 324 - A steam launch moving quickly through the water is accompanied by a peculiar system of diverging waves, of which the most striking feature is the obliquity of the line containing the greatest elevations of successive waves to the wave-fronts. This wave pattern may be explained by the superposition of two (or more) infinite
Page 475 - t. Hence, in passing through zero, the amplitude changes sign, which is equivalent to a change of phase of 180°, if the amplitude be regarded as always positive. This change of phase is readily detected by measurement in drawings traced by machines for compounding vibrations.
Page 394 - For example, if the diameter be one millimetre, the disturbance is multiplied 1000 fold in about onefortieth of a second. In view of these estimates the rapid disintegration of a fine jet of water will not cause surprise. The relative importance of two harmonic disturbances depends upon their initial magnitudes, and upon the
Page 92 - under the form D : D', which is a simple number and may therefore be omitted. It remains to find how i varies with T, r, \, b. Now, of these quantities, b is the only one depending on time; and therefore, as i is of no dimensions in time, b cannot occur in its expression. We are left, then, with T, r, and