Magnetic State of Iron and its Photo- Electric Properties, 339 



5. A discussion of principles which may be utilized in the 



prediction of isotopes is presented. The most im- 

 portant relations are that the ratio N/P of electrons 

 to protons is never less than 1/2 for stable atomic 

 species, and the number of isotopes is considerably 

 greater in general for elements of even, than for 

 elements of odd atomic number. 



6. An hypothesis concerning the general structural rel- 



ations of atom nuclei, is presented. 



7. Mr. C. E. Broeker and the writer made a partial 



separation of chlorine into lighter and heavier 

 isotopes, but this work was suddenly stopped by the 

 death of Mr. Broeker in May 1920. It is now being 

 continued by Mr. Anson Hayes. 



University of Chicago, 

 Feb. 28, 1921. 



XL, On a Possible Connexion between the Magnetic State 

 of Iron and its Photo-Electric Properties. By J. H. J. 

 Poole, M.A.* 



IT is generally considered that the electrons present in the 

 atom may be roughly classified somewhat as follows : — 



(1) Nuclear electrons ; 



(2) Free or conductivity electrons ; 



(3) Dispersional or emission electrons ; 



(4) Valency electrons ; 



(5) Photo-electric electrons; 



&nd in ferro-magnetic substances a sixth class must be added, 

 i. e., revolving electrons, necessary to account for the 

 magnetic properties of the substance. 



It seems highly probable, however, that these classes are 

 not in reality mutually exclusive, and the question then 

 arises as to which of ttiese classes of electrons can be con- 

 sidered to be identical. Thus there are reasons for holding 

 that the valency and dispersional electrons are really iden- 

 tical, but it is with an attempt to obtain some evidence that 

 in ferro-magnetic substances the magnetic and photo-electric 

 electrons are the same that this paper deals. 



That there is good ground for believing that this hypo- 

 thesis is correct, seems probable from the fact that both the 

 magnetic and photo-electric properties of an element depend 



* Communicated by Prof. J. Jolv, F.R.S. 

 2 A2 



