Manchester Memoirs, Vol li. (1907), No. <>. 



VI. The Grouping of the Chemical Elements, 



By C. E. Stromeyer, M.InstC.E. 



Received and read January 15th, 1907. 



This enquiry was started like many others in the hope 

 of finding a formula which would express the atomic 

 weights in terms of the positions in Mendeleeff's groups 

 of chemical elements, but a few preliminary attempts led 

 to the conviction that the formula would have to represent 

 an undulating curve, and not a simple one like that 

 suggested by Stoney. Also, all attempts to adopt periods 

 of 16 group intervals or their multiples or parts failed, 

 but by rearranging the chemical elements, regardless of 

 their properties, in 15, 14, and fewer groups, a certain 

 amount of harmony was discovered for systems having 

 12, 24, and 48 groups, and the following formula is the 

 result : — 



2.48 • N.tt , 4.24 . N.7T , 8.12 . N. 

 A= 2-788. . N-o'o-i-f -_±-sin — _, + z_3sin + — — -sin 



12 J 



N 48 N ' 24 N 

 which may be written 



A = 2-788 . . N - 6-o + 3 °5 . ( - sin N. 3-75° + sinN.7'5 + sinN.15 J. 



Here A is the atomic weight of the element which is 

 separated from Helium by N group intervals. 



A slight improvement might have been effected in 

 the above formula by introducing a term of the form 



C.sin — -, also by replacing 2-788 . . by 2-78 



7 



and by modifying some of the coefficients to suit, but it 

 had already become evident that the formula is of no 



March yth, ipo/. 



