33* 



Mr. H. Bell on Atomic Number and 



In connexion with the discovery o£ triplet differences in 

 the Radium spectrum, the Misses Anslow and Howell * have 

 reinvestigated the alkaline earth column, plotting, however, 

 against log (atomic number), not log (doublet difference), as 

 was done in the above paper, but the logarithm of (v x 4 v 2 ). 

 They obtain graphically good agreement with this law. They 

 state also that the linearity is between alternate members of 

 the same Mendelejeff column, a point of view which we shall 

 have to modify. 



There is reproduced below for reference a form of the 

 atomic number table as given by Kossel f. 



0. 



I. 



II. 



III. 



IV. 



V. 



VI. 



VII 



VIII. 







H 

 1 





















He 



Li 



3 



Be 

 4 



B 



5 



c 



6 



N 



O 



8 



Fl 



9 









Ne 

 10 



Na 

 11 



Mg 

 12 



Al 



13 



Si 

 14 



P 



15 



S 

 16 



CI 

 17 









Ar 



18 



K 



19 



Oa 



20 



Sc 

 21 



Ti 

 22 



V 

 23 



Cr 

 24 



Mn 

 25 



Fe 



26 



Co 



27 



m 



28 





Cu 



29 



Zn 



30 



Ga 

 31 



Ge 

 32 



As 

 33 



Se 

 34 



Br 



35 









Kr 



36 



Eb 



37 



Sr 

 38 



Y 



39 



Zr 



40 



Nb 

 41 



Mo 

 42 



43 



Ku 



44 



Eh 



45 



Pd 



46 





Ag 



47 



Cd 



48 



In 



49 



Sn 

 50 



Sb 

 51 



Te 



52 



I 



53 









X 



54 



Cs 

 55 



Ba 



56 



Earths 



72 



Ta 

 73 



W 



74 



75 



Os 

 76 



Ir 



77 



Pt 



78 





Au 

 79 



Hg 



80 



Tl 



81 



Pb 



82 



Bi 



83 



84 



85 









Eman. 

 86 



87 



Ea 



88 



89 



Th 

 90 



91 



U 



92 











In the two diagrams shown herewith the square root of 

 wave-number difference per cm. is plotted against atomic 

 number N as abscissa. Unless otherwise stated, the data 

 have been taken from Dunz's Bearbeitimg unserer Kentnisse 

 von den Serien if, with the result that, in general, the wave- 

 number differences refer, not to any particular member of a 

 series, but to the calculated limiting frequencies. 



Fig. 1 shows the result for the Lithium column, the con- 

 stituents having only doublet series. s/v is seen to be linear. 



* Proc. Nat. Acad. Sciences, iii. p. 409 (1917). 

 t Ann. d. Phys. lix. p. 247 (1916). 

 X Dissertation, Tubingen, 1911. 



