Double-Layer of Solid and Liquid Bodies. 315 



where a is equal to the radius of the first stationary circular 

 orbit for hydrogen (k=1). If the influence of internal 

 electronic rings on the external one is reduced to a simple 

 diminution of the effective central charge, as was assumed 

 throughout this work, then formula (15) determines the 

 possible radii of an atom whose valency is equal to k. It is 

 at once clear from this formula that the atomic radii must 

 decrease with the valency, provided i is the same for different 

 atoms. 



As we shall see, this condition seems to be satisfied in the 

 case of many metals in the solid or liquid state, the atomic 

 radii being determined by the universal condition 



*=2, . -, (16) 



in conjunction with (15). 



In the following Table (IV.), some of the values of r, 

 calculated from the surface-tension and taken from Table II., 

 are compared with the values r 2 , calculated on Bohr's theory 

 by means of (15) and (16) on the one hand, and with half 

 the inter-atomic distances R on the other. The values of s* 



ar« given in column III. 



Table IV. — Atomic radii and Bohr's theory. 



I. 



II. 



III. 



IV. 



■^ inter- 



V. 



Atomic 

 radius 



VI. 



Atomic 

 radius 



VII. 



Element. 



Valency 



V 



atomic 

 distance 

 Ex 10 s . 



(calc. 

 from 



(rorV) 

 rxl0*. 



(calc. on 

 Bohr's 

 theory) 

 r. 2 Xl0 8 . 



r/r 2 . 



K 



1 







2-00 



2-58 



2*2 



115 



Hg 



2 



0-25 



1-40 



1-36 



1-26 



1-08 



C 



4 



096 



105 



0-65* 



073 



09 



Pb 



4 



0-96 



1-49 



0-99 



0-73 



1-35 



So 



5 



1-38 



1-46 



0-68 



0-61 



111 



Ta 



5 



1-38 



1-27 



0-74* 



061 



1-21 



W 



6 



1-83 



118 



0-61* 



0-53 



115 



Fe 



8 



2-81 



111 



0-42 



043 



098 



* These values are calculated from the thermionic effect 

 others are calculated from the surface-tension. 



all the 



The parallelism between the values in columns V. and VI. 

 is obvious, although the former are somewhat larger than the 

 latter. 



Y2 



