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 body cause Cavendish Laboratory conductivity conductor cubic centimetre definite deflexion difficulties direction discharge discovery dissipation 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 important increased investigation ionized J. J. Thomson kathode rays lecture Lord Kelvin Lord Rayleigh magnetic deflexion magnetic field magnetic forces mass matter Maxwell means measured medium methods millimetre molecular molecules motion nature needle negative charge negative electricity negative ions number of ions observed obtained particle phenomena physical plates Polonium 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 substances sufficient surface terrestrial magnetism theoretical theory of light thorium transmitted ultimate University uranium velocity vibration wave
Popular passages
Page 68 - 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 8 - 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 25 - 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 72 - 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 115 - 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 25 - 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 116 - 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 9 - 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...
Page 7 - This characteristic of modern experiments — that they consist principally of measurements, — is so prominent, that the opinion seems to have got abroad, that in a few years all the great physical constants will have been approximately estimated, and that the only occupation which will then be left to men of science will be to carry on these measurements to another place of decimals.
Page 26 - There appear to be three distinct functions which are recognized as pertaining to the university : one is that of examination, one that of teaching, one that of fostering original research. The first of these three has practically been as yet most regarded ; and many of us hope that it will in future decline either absolutely or relatively by the increased development of the other two.