574 



NATURE 



[October 5, 1905 



ELECTRONS AND MATTER. 



"T^HE inaugural address on " Electronen en Materie," 

 ■*■ delivered by Prof. C. H. Wind upon taking the 

 chair of mathematical physics and theoretical mechanics 

 at the University of Utrecht on February 20 of this year, 

 has lately been published (Leyden : A. \V. Sijthoff). 

 Beginning with a brief account of the gradual development 

 of the conception of electrons, mainly through the works of 

 H. A. Lorentz, and of its sudden corroboration after the 

 discoveries made by Zeeman and Rontgen, the address 

 goes on with an exposition of the notions of ether, electric 

 displacement, electrons, and magnetic force in their pre- 

 sent form, and traces the way to the idea of an electro- 

 magnetic mass of the electrons. 



The measurements made by Kauffmann, though showing 

 that these particles of matter probably do not possess 

 any mass besides this electromagnetic one, of course do 

 not prove that the same should be the case with all other 

 particles of matter in our universe, as Wien had suggested. 

 Yet they make this suggestion — the basis of what the 

 author calls an electron theory a outratice — to some e.xtent 

 a plausible one. Several of the brilliant and fascinating 

 views which this ultimate theory opens having been ex- 

 pounded by Mr. Balfour in his presidential address at the 

 Cambridge meeting of the British .Association, the present 

 author directs attention to those concerning the structure 

 of atoms, mechanism of radiation, and origin of chemical 

 differences. He also enters into some more details, and, 

 assuming for a while that an atom of hydrogen consists 

 of a single positive and a single negative electron, calcu- 

 lates that in this svstem the two components would be 

 separated by a distance perhaps 100,000 times greater 

 than the diameter of the largest of them, and that there 

 must be stored up in the atoms constituting one gram 

 of hydrogen an amount of energy equivalent to that re- 

 quired by a mail steamer to cross the .Atlantic ten times. 



Poincar^ has raised several serious objections against 

 the theory. Some of these relate to the temperate electron 

 theory only, and lose their weight as soon as the ultimate 

 theory is adopted. To take an example. Poincar^ does 

 not feel satisfied with the changes of length in solid bodies 

 owing to their motion through ether, as suggested by 

 Lorentz and by Fitzgerald in order to explain the result 

 of Michelson's experiments. Lorentz himself, however, 

 has already shown that this hypothesis, though appearing 

 rather bold at first sight, becomes plausible as soon as 

 molecular forces and masses are supposed to be in the 

 same way as electromagnetic ones affected by a translation 

 through ether ; and it is clear that this supposition is 

 involved in that of all matter consisting of electrons, which 

 therefore at once clears the way. 



The second category of objections, those arising from 

 the dependency of electromagnetic mass upon velocity and 

 direction of motion, from so many instances of unequal 

 action and reaction, from the violation even of the law 

 of inertia, whenever electrons move with a higher speed 

 than light, are, on the other hand, most serious in the 

 light of the ultimate electron hypothesis, whereas the 

 temperate theory has a way left open to dispose of them. 

 The latter theory, indeed, does not deny the existence of 

 matter apart from electrons and considers electromagnetic 

 mass as something se ondary. By assuming as con- 

 stituents of ether hidie;; i natter, obeying the classical 

 principles just as well as ordinary or coarse matter, this 

 theory will be able to account for every apparent deviation 

 from the principles which by mathematical reasoning 

 should be deducted as occurring in ccarse matter. 



But if by progress of experiment and theory the electron 

 hypothesis in its ultimate form should continue to gain 

 ground if it should finally prove unavoidable to accept 

 the view that matter consists entirely of electrons, then 

 mass and momentum would cease to be what thev are 

 now in our ideas, quantities strictly invariable. There is 

 no denying that this would involve a serious change of 

 our general conception of nature. For the predilection and 

 confidence with which science has for centuries been aim- 

 ing at a description of the physical universe in terms only 

 of matter and motion were based chiefly — though half 

 unconsciously — on the idea of mass and momentum being 

 invariable elements of nature, images or pictures of in- 



NO. 1875, VOL. 72] 



variable elements of reality itself. Now this idea, sc 

 fundamental to our whole mechanical conception of nature, 

 would shrink into an illusion in the light of the new 

 theory. Of course, there would be a great advantage also. 

 Whereas it seems now almost hopeless to involve electro- 

 magnetic phenomena in a description in terms only of 

 matter and motion, the unity desired in our picture of the 

 phvsical world would then be secured by putting it in 

 terms of electrons and motion. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



We learn from Science that an anonymous gift has beerf 

 made to the Lebanon Valley College, Annville, Pa., of a 

 hall of science to cost 16,000/. 



Mr. F. R. B. Watson has been appointed assistant 

 lecturer and demonstrator in engineering at the Merchant 

 Venturers' Technical College, Bristol. 



A Reuter message from New York states that the 

 American General Education Board has received from Mr. 

 John Rockefeller cheques to the amount of 2,000,000/., in 

 pursuance of his promise last June to give that amount in 

 cash or securities for the endowment of higher education. 



A PRIZE of 50/. out of the Gordon-Wigan fund will be 

 awarded at the end of the Easter term, 1906, for a research 

 in chemistry, of sufficient merit, carried out in the Uni- 

 versity of Cambridge. The research may be in any branch 

 of chemistry. The dissertation, with the details of the 

 research, must be sent to the professor of chemistry not 

 later than the division of the Easter term, igo6. 



The year-book of the faculty of engineering of the 

 University of Liverpool (1905-6) shows that the courses 

 of study are so arranged as to afford a general scientific 

 training for those intending to become engineers. The 

 honours course affords opportunities for specialisation in a 

 selected branch of the profession. The university training, 

 which extends over three years, is preliminary to or sup- 

 plementary of pupilage under an engineer or apprentice- 

 ship with an engineering firm. 



It is announced in Science that the University of 

 Pennsylvania will receive 12,000/. from the estate of the 

 late Prof. Maxwell SommerviUe, who held a chair of 

 archa?oIogy in the university. President Thwing, of 

 W'estern Reserve University, we learn from the same 

 source, has announced that Mr. .Andrew Carnegie has 

 given 5000/. towards the establishment of a fund of 

 20,000/. for the endowment of a chair of political economy 

 at Western Reserve L^niversity, to bear the name of the 

 late Senator Hanna. 



The Engineering and Mining Journal publishes the 

 presidential address delivered by -Mr. F. W. McNair before 

 the Society for the F'romotion of Engineering Education, in 

 which he shows that the American mining schools have 

 amply proved the necessity for their existence. Froni 

 statistics of the six largest mining schools in America, ho 

 shows that the ratio of graduation to enrolment is in- 

 creasing, that there is an enormous percentage increase 

 in students enrolled, and that the mining school product 

 is gradually taking the place of the so-called practical 

 man. Dividing the twelve years available for comparison 

 into three periods of four years, it is shown that thr- 

 schools under consideration graduated one man to i3-(7 

 million tons of the total mineral production during the 

 first period, one to 102 millions in the second period, and 

 one to 9-4 millions in the last period. 



In connection with the department of geography of the 

 University of Cambridge, special public lectures' will be 

 delivered in the Michaelmas term bv Sir Clements R. 

 Markham, K.C.B., F.R.S., and Sir Archibald Geikie, 

 F.R.S. The following courses, which are open to alt 

 students, whether members of the university or not, 

 have also been arranged: — A general course in geography 

 (with practical work) will be given bv Mr. H. Yule Old- 

 ham ; courses on the geography of Europe, on the prin- 

 ciples of physical geography, and on the history of 

 geographical discovery will also be given by Mr. Oldham. 

 Dr. J. E. Marr, F.R.S., will lecture twice weekly on 

 geomorphology ; Dr. A. C. Haddon, F.R.S., will ' give 

 courses on ethnology and on anthropogeography ; and Mr. 



