Manchester Memoirs, Vol. li. (1907), No. 0. 



Elements. 



Atomic 

 Weights. 



Group 

 Position. 



Calculated 

 At. Wt. 



Difference. 



Group XII„ 



Mean (second) position, 13 '2 7. 



Silicon ] Si 



Germanium ... Ge 



Tin Su 



Erbium Er 



Lead ! Pb 



2 8 "40 



72-50 



119*00 



166*00 



206*90 



12 



09 



12 



38 



13 



12 



1 3 '43 



12 



M 



30-82 



75-00 



119-46 



165-57 



2IO'OI 



— 2-42 

 -2-50 



— 0*46 

 + 0-43 



-3-11 



Group XIII. 



Mean position, 13*38. 



Phosphorus ... 



P 



31-00 



r 3"37 



31-01 



— O'OI 



Arsenic 



As 



75-00 

 12000 



13-27 



75"3° 

 1 19-80 



-0-30 



+ 0*20 



Antimony 



Sb 



Bismuth 



Bi 



208-50 



12*72 



210*30 



- t*8o 







Group XIV. 



Sulphur 



Selenium 



Tellurium 



Mean position undefined. 



S 



Se 



Te 



32*06 



79*20 



127*60 



1387 

 14*80 



i5'9i 



