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THE POPULAR SCIENCE MONTHLY 



charges Avhieh cau be put on a given 

 body than Dalton had ever discoverjd 

 between combining powers or Front be- 

 tween atomic weights or Moseley be- 

 tween X-ray frequencies. The greatest 

 common divisor of this series of chargc-s 

 is then the ultimate unit or atom of 

 electricity which has been named the 

 "electron." New evidence that it is 

 indeed a universal and invariable nat- 

 ural constant will be brought forward 

 and a new determination of its value 

 will be presented. 



It is obvious that as soon as we could 

 assert that these electrons are found in 

 the hydrogen atom it was necessary to 

 suppose that a single hydrogen atom 

 contains at least two such electrons, one 

 positive and one negative, and as a. 

 matter of fact the evidence is now 

 strong that it consists of exactly two. 

 This twentieth century has then dis- 

 covered for the first time a new sub- 

 atomic world of electrons, the constitu- 

 ents of atoms. 



All this is definite and probably 

 permanent. But atomic conceptions in 

 more or less vague form have also be- 

 gun to invade the one remaining field 

 of physical investigation, namely, the 

 field of ethereal radiations. The most 

 significant of recently discovered facrs 

 in the domain of radiant energy are 

 these : 



(1) Ethereal radiations when ab- 

 sorbed by matter, if they are of high 

 enough frequency, will detach one and 

 only one electron from a single atom. 

 (2) The energy transferred to this 

 electron from the ether wave is inde- 

 pendent of the intensity of the incident 

 radiation. (3) It is also independent 

 of the kind of matter from which the 

 electron is taken, but (4) it is exactly 

 proportional to the frequency of the 

 ether wave which detaches it. 



These facts are stated in an equa- 

 tion set up tentatively by Einstein in 

 190.5, and arrived at by him from the 

 standpoint of a modified corpuscular 

 theory of radiation. New proofs of the 



exactness of Einstein's equation will be 

 presented and the evidence for and 

 against Einstein 's conception will be 

 discussed. Whether the conception ulti- 

 mately stands or falls, it appears prob- 

 able, at any rate, that an equation has 

 been obtained which is to be of no less 

 im])ortanee in future ph-^sies than Max- 

 well's equation of the electro-magnetic 

 field, and which seems destined to un- 

 doors to the understanding of the rela- 

 lock for the physicists of the future the 

 tions existing between matter and radi- 

 ant ener""t^. 



SCIENTIFIC ITEMS 



We record with regret the death of 

 Dr. Frederick Winslow Taylor, of Phil- 

 adelphia, past president of the Society 

 of Mechanical Engineers, known for 

 his inauguration of methods of "scien-. 

 tific management"; of Dr. Edith J. 

 Claypole, research associate in pathol- 

 ogy in the University of California; of 

 Dr. A. A. W. Hubrecht, professor of 

 embryology in the University of 

 Utrecht; of Professor Stanislaus von 

 Prowasek, head of the zoological de- 

 partment of the Hamburg Institute for 

 Tropic Diseases; of Sir George Turner, 

 distinguished for his work on the rind- 

 erpest and on leprosy, from leprosy, 

 contracted during research Avork to dis- 

 cover a cure for the disease, and of 

 Lady Huggins, widow of Sir William 

 Huggins, the distinguished astronomer, 

 and known for her scientific work. 



Miss Davy, niece of Sir Humphry 

 Davy, has presented to the Eoyal Insti- 

 tution, London, a bust of the great 

 chemist executed by Samuel Joseph in 

 1822. 



The Eoyal Astronomical Society has 

 by a vote of 59 to 3 passed a resolution 

 approving of the admission of women 

 as fellows and associates of the society, 

 and requesting the council to take all 

 necessary steps to render their election 

 possible. 



