94 
Proceedings of the Royal Irish Academy, 
The central elements alternate as before between the lineal and 
cubic branches, viz. — 
Mn cubic, Mn {his) 57 lineal, 
Cu lineal, Cu {his) 64 cubic, 
Zn cubic, Zn {lis) 66 lineal, 
with a possibility of forming three other elements near them, which 
have not come into existence. 
The remaining elements are formed in pairs on the lineal branch, 
in the two gaps of the cubic branch, where two roots become imagi- 
nary, viz. Ti I Ya, with a possibility of another element of atomic 
weight 50, forming a monad on the cubic at the opposite side, and, 
in the other gap, Ga | Ge | , with the possibility of another monad 
element of atomic weight 69^ at the opposite side. 
["Note, see p. 96. 
