The Progress of Physics During 33 Years (1875-1908): Four Lectures Delivered to the University of Calcutta During March 1908At the University Press, 1911 - 164 pages |
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æther atmosphere atom axis Balfour Stewart Berkeley Berkeley body CALIFORNIA LIBRARY cause Cavendish Laboratory conductivity conductor cubic centimetre definite deflexion difficulties direction discharge discovery diurnal earth effect electric currents electric force electrification electro-magnetic electro-motive force electrolyte electrons emitted energy equal experimental experiments explain gases helium Helmholtz hypothesis idea increased investigation ionized J. J. Thomson kathode rays lecture Lord Kelvin Lord Rayleigh magnetic deflexion magnetic field magnetic forces mass matter Maxwell Maxwell's means measured medium ment millimetre molecular molecules motion nature needle negative charge negative ions number of ions observed obtained particle phenomena physical positive charge positive ions present properties quantity of electricity radiation radio-active radium recognised recombination result Roentgen rays scientific secular variation shew shewn space student sufficient surface terrestrial magnetism theoretical theory of light thorium transmitted ultimate UNIVERSITY OF CALIFORNIA uranium velocity vibration wave
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Page 63 - Now the most startling result of Faraday's law Is perhaps this. If we accept the hypothesis that the elementary substances are composed of atoms, we cannot avoid concluding that electricity also, positive as well as negative, is divided into definite elementary portions, which behave like atoms of electricity.
Page 66 - Thus on this view we have in the cathode rays matter in a new state, a state in which the subdivision of matter is carried very much further than in the ordinary gaseous state: a state in which all matter, - that is, matter derived from different sources such as hydrogen, oxygen, and carbon, - is of one and the same kind; this matter being the substance from which all the chemical elements are built up.
Page 6 - But the history of science shows that even during that phase of her progress in which she devotes herself to improving the accuracy of the numerical measurement of quantities with which she has long been familiar, she is preparing the materials for the subjugation of new regions, which would have remained unknown if she had been contented with the rough methods of her early pioneers.
Page 23 - It may be said that the fact makes a stronger impression on the boy through the medium of his sight, that he believes it the more confidently. I say that this ought not to be the case. If he does not believe the statements of his tutor— probably a clergyman of mature knowledge, recognized ability, and blameless character— his suspicion is irrational, and manifests a want of the power of appreciating evidence, a want fatal to his success in that branch of science which he is supposed to be cultivating.
Page 70 - the atom as containing a large number of smaller bodies," which he calls "corpuscles," and these are equal to one another. "In the normal atom this assemblage of corpuscles forms a system which is electrically neutral.
Page 69 - ... as containing a large number of smaller bodies which I will call corpuscles; these corpuscles are equal to each other; the mass of a corpuscle is the mass of the negative ion in a gas at low pressure, ie about 8 x 10~26 of a gramme.
Page 113 - To use an acute and familiar expression of Gustav Kirchhoff, it is the object of science to describe natural phenomena, not to explain them. When we have expressed by an equation the correct relationship between different natural phenomena we have gone as far as we safely can, and if we go beyond we are entering on purely speculative ground.
Page 23 - That this remark was not made jocularly is shewn by a passage which occurs in an essay on the Conflict of Studies, in which Todhunter discusses the advisability of introducing experimental illustrations into the lessons given in schools. He declares himself as opposed to it on the ground, that an experiment which is not intended to bring...
Page 114 - We may never know what constitutes atoms, or what is the real structure of the aether ; why trouble, therefore, it is said, to find out more about them. Is it not safer, on the contrary, to confine ourselves to a general talk on entropy, luminiferous vectors, and undefined symbols expressing vaguely certain physical relationships.? What really lies at the bottom of the great fascination which these new doctrines exert on the present generation is sheer cowardice ; the fear of having its errors brought...
Page 7 - Our principal work in the laboratory must be to acquaint ourselves with all kinds of scientific methods, to compare them and to estimate their value. It will, I think, be a result worthy of our University, and more likely to be accomplished here than in any private laboratory, if, by the...