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absorption according amplitude aperture axis bands calculated centre change of phase circle coefficient coincident colours components considered constant cos2 crystal curve difference in optical difference in phase diffraction direction of vibration displacement disturbance effect elastic ellipse ellipsoid energy equal equation Fermat's principle Fresnel's gives grating Hence incident light inclined intensity interference intersection lens Lord Rayleigh magnetic maximum measured medium molecules Newton's rings observed obtain optic axes optical distance optical length oscillations parallel particle passing path periodic motion plane of incidence plane of polarization plane wave plate portion position prism proportional quantity radiations radius reflected reflexion refractive index represented resolving power resultant retardation right angles rings rotation screen shows sin2 slit spectroscope spectrum sphere square surface telescope theory thickness transmitted velocity velocity of propagation wave plate wave propagation wave-front wave-length wave-surface zero zones
Page 150 - The image of the sun thrown on a screen at a distance exceeding 66 feet, through a hole i inch in diameter, is therefore at least as well defined as that seen direct. In practice it would be better defined, as the direct image is far from perfect. If the image on the screen be regarded from a distance /, it will appear of its natural angular magnitude.
Page 233 - If, however, this were not the case, we are so perfectly ignorant of the mode of action of the elements of the luminiferous ether on each other, that it would seem a safer method to take some general physical principle as the basis of our reasoning, rather than assume certain modes of action...
Page 151 - Seen from a distance less than / it will appear magnified. Inasmuch as the arrangement affords a view of the sun with full definition and with an increased apparent magnitude, the name of a telescope can hardly be denied to it. "As the minimum focal length increases with the square of the aperture, a quite impracticable distance would be required to rival the resolving-power of a modern telescope. Even for an aperture of four inches /i would be five miles.
Page 336 - No theory of evolution can be formed to account for the similarity of molecules, for evolution necessarily implies continuous change, and the molecule is incapable of growth or decay, of generation or destruction. None of the processes...
Page v - who believe in the possibility of a mechanical conception of the universe, and are not willing to abandon the methods which from the time of Galileo and Newton have uniformly and exclusively led to success, must look with the gravest concern on a growing school of scientific thought which rests content with equations correctly representing numerical relationships between different phenomena, even though no precise meaning can be attached to the symbols used.
Page 82 - ... nearly equal angles from the apertures at all distances, and wider also in the same proportion as the apertures are closer to each other. The middle ... is always light, and the bright stripes on each side are at such distances, that the light coming to them from one of the apertures must have passed through a longer space than that which comes from the other by an interval which is equal to the breadth of one, two, three or more of the supposed undulations...
Page 82 - In order that the effects of two portions of light may be thus combined, it is necessary that they be derived from the same origin, and that they arrive at the same point by different paths, in directions not much deviating from each other.
Page 233 - Light those formulas which represent the motions of a system of molecules acting on each other by mutually attractive and repulsive forces ; supposing always that in the mutual action of any two particles, the particles may be regarded as points animated by forces directed along the right line which joins- them. This last supposition, if applied to those compound particles, at least, which are separable by mechanical division, seems rather restrictive ; as many phenomena, those of crystallization...
Page 233 - of the advantages of this method, of great importance, is that we are " necessarily led by the mere process of the calculation, and with little care "on our part, to all the equations and conditions which are requisite and "sufficient for the complete solution of any problem to which it may be "applied.