1864.] Opute on the Proportional Numbers of the Elements. 643 
With what case this purely arithmetical seriation may be made to 
accord with a horizontal arrangement of the elements according to 
their usually received groupings, is shown in the following table, in 
the first three columns of which the numerical sequence is perfect, 
while in the other two the irregularities are but very few and 
trivial :— ; 
Ro 104 Pt 197 
Ru 104 Ir 197 
Pt 106+5 Os 199 
aes ad : Ag 108 Au 196°5 
‘ , Zn 65 Cd 112 Hg 200....... 
i Boe eT B : T1 203 
Gy 9 re . 4 Pb. 20Tiote. cs 
Beer |) %Al 27°5 : U 120 S 
Cc 12] Si 28 : Sar diene: ate. Seal se 5 
Nes | Pp St As 75 Sb 122 Bi 210 
Ow ie | 's¥ 32 Se 79-5 | Te 129...).... Mi 
ieee F 19 | Cl 35:5 | Br 80 Ey g7 z 
lr. Na 23 | K_ 39 Rb 85 Cs 133 i 
Mg 24 Ca 40 Sr 87°5 13, BIS coe sy ote eeealan seat 
Ti 50 Zr 89-5 | Ta 138 Th 231-5! 
D Ce 92 5 
Cr 52:5 | Mo 96 Va ISiic eee 
Mn 55 M 184 
Fe 56 
Co 59 
Ni 59 
Cu 63°5 
If we compare together certain pairs of more or less analogous 
elements, we find in a considerable number of instances, embracing 
one-half the entire number of elements, a difference in atomic 
weight ranging from 845 to 97, as shown in the following table :— 
