On Light: First Course, On the Nature of Light Delivered at Aberdeen in November, 1883, Volume 1 |
Other editions - View all
Common terms and phrases
according accordingly analyzer angle of incidence aperture axis beam block of Iceland colours common light crystal crystalline plate dark difference of path diffraction distance disturbance double refraction earth ether existence of rays explanation external fringes extraordinary Fresnel Fresnel's laws geometrical shadow glass hole Huygens Iceland spar illuminated incident light intensity interposed laws of reflection lectures light consists luminous point Malus's law medium nature of light nearly Newton's rings observation opaque screen ordinary particles perpendicular incidence phenomena of interference plane of incidence plane of polarization plane of primitive plate of air polarized in rectangular polarized light ponderable matter primitive polarization principal plane principle properties rectangular planes rectilinear propagation reflection and refraction refractive index refrangibility respect rhomb seen sound straight edge substance suppose supposition surface theory of emission theory of transverse theory of undulations thickness thin plates tion transmitted transverse vibrations velocity of light velocity of propagation wave length
Popular passages
Page 16 - ... a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting continuously according to certain laws; but whether this agent be material or immaterial, I have left to the consideration of my readers.
Page v - ... the Evidence that there is a Being, all-powerful, wise, and good, by whom every thing exists, and particularly to obviate difficulties regarding the Wisdom and Goodness of the Deity : in the first place, from considerations independent of written revelation ; and in the second place, from the revelation of the Lord Jesus ; and from the whole, to point out the inferences most necessary for, and useful to, mankind.
Page vi - The evidence that there is a Being, all-powerful, wise, and good, by whom every thing exists ; and particularly, to obviate difficulties regarding the wisdom and goodness of the Deity ; and this, in the first place, from considerations independent of written revelation, and, in the second place, from the Revelation of the Lord Jesus ; and from the whole, to point out the inferences most necessary for and useful to mankind.
Page 25 - ... be content to learn new laws and properties of natural objects. It shows that we are not to be disheartened by some preliminary difficulties from giving a patient hearing to a hypothesis of fair promise, assuming of course that those difficulties are not of the nature of contradictions between the results of observations or experiment, and conclusions certainly deducible from the hypothesis on trial.
Page 15 - ... know — not only in the spectrum we can see or photograph, but far beyond that. And secondly, this difficulty of being able to accept such " a large order " was just the sort of difficulty people found with the undulatory theory ; and I will again quote an example given by Sir George Stokes : — The necessity of thus filling space with substance seems to have presented a serious difficulty to some minds. In the course of a conversation with Sir David Brewster, who had just returned from France,...
Page 26 - It shows that we are not to be disheartened by some preliminary difficulties from giving a patient hearing to a hypothesis of fair promise, assuming of course that those difficulties are not of the nature of contradictions between the results of observation or experiment, and conclusions certainly deducible from the hypothesis on trial. It shows that we are not to attach too great importance to great names, but to investigate in an unbiased manner the facts which lie open to our examination.
Page 19 - Huyghens' principle, he says (p. 19) : — " This principle does not by itself suffice for the explanation of rays. It proves, or at least appears to prove, too much. It is as applicable to sound as, on the supposition that light consists in undulations, it is to light ; and if Huyghens' explanation of rays were complete, there ought equally to be rays of sound, and sound ought to present the same sharp shadows as light.
Page 25 - Surely the subject is of more than purely historical interest. It teaches lessons for our future guidance in the pursuit of truth. It shows that we are not to expect to evolve the system of nature out of the depths of our inner consciousness, but to follow the painstaking inductive method of studying the phenomena presented to us, and be content to learn new laws and properties of natural objects. It shows that we are not to be disheartened by some preliminary difficulties from giving a patient hearing...
Page 10 - Since the aberration of a star depends on the ratio of the velocity of light to that of the earth, if various coloured lights haddifferentvelocities, the star would appear a complete spectrum.
Page 24 - To estimate the need there was of such an union of prudence with fidelity, it may be well to pause for a moment, and consider the position of things at Zurich.