326 Dr. A. W. Stewart on Atomic Structure 



X'= — ^— -, &c. = Ax' &c, 

 we have to evaluate 



^-^rx'dx' dy'dz'. 



Cr—r' 

 This is = \ '—^~^ da' dy' dz\ 



where V^2= potential due to a distribution of density 



varying as x 2 



aVF > d\ 



-H{»-*+sS} 



and 



+ X)Q' 



r a» ?/ 2 ^ 2 | [Routh, < Statics/ 



t tf + X & 2 + X c 2 + A,J vol. ii.] 



A generalization of the above theory as well as its appli- 

 cation to the case of the earth will be considered in a later 

 paper. 



XXXV. Atomic Structure from the Physico- Chemical 

 Standpoint. By Alfred W. Stewart, D.Sc* 

 fllHE theories put forward up to the present with regard to 

 JL the structure of the atom have been based mainly upon 

 physical data ; but since the problem is a two-fold one, it 

 appears possible that further light may be thrown upon it by 

 a consideration of the chemical side of the question. Neither 

 view alone will suffice to cover the whole ground ; and the 

 following is put forward with the idea of showing the 

 essentials of the matter from the chemical standpoint, in the 

 hope that it may prove suggestive to those who have hitherto 

 regarded the problem chiefly from the physical aspect. 



Any complete theory of atomic structure must account for 

 the following facts concerning the elements : — 



(1) That a- and /3-ray changes are independent processes. 



(2) That the electrons involved in valency changes oc- 



curring during ordinary chemical reactions originate 

 in a region of the atom different from that occupied 

 by the electrons which are ejected during /3-ray 

 changes. 



* Communicated by the Author. 



