1864.] Opting on the Proportional Numbers of the Elements. 645 
closely thereto; and in seven of these instances, the element of 
lowest atomic weight is the first member, and the element compared 
therewith the second member of the group to which they both 
belong, or may be considered to belong, as shown in the following 
table, which includes nearly one-third of the entire number of 
elements : 
Cl - #F or | 38o%5 — 19 = 16s0 
K — Na 39° — 23 LG 
Na - L 235 = i iG 
Mo — Se 96 — 80 = il 
Ss — ©) 32 — 16 = i¢ 
Ca —- Mg 40 — 24 = IG 
Mg - G 24 - 9 = 15 
12 —- N he oc ale = ly 
Als — B 275 — Iii == Kae 
si - C 23° v= 12 = US 
In looking over the above tables, we can scarcely help noticing 
that those elements whose resemblance to one another is most 
pronounced, have a difference of about 48 between their respective 
atomic weights, that is to say, the largest difference in atomic weight 
known to exist between what are conceived to be proximate elements, 
as shown in the following table, which also includes nearly one-third 
of the entire number of elements. For example, the resemblance of 
cadmium to zinc, where the difference in atomic weight is 47, is 
greater than the resemblance of zinc to magnesium, where the 
difference is 41; while the resemblance of antimony to arsenic, 
where the difference is again 47, is greater than the resemblance of 
arsenic to phosphorus, where the difference is 44. Moreover, the 
co-resemblances of cesium, rubidium, and potassium, and of barium, 
strontium, and calcium, with a common difference of about 48 between 
the proximate members, are far closer than the co-resemblances of 
potassium and sodium, and of calcium and magnesium respectively, 
with a difference of 16 in each instance :— 
by mn 65 + 47 Ca 112 - 
%; As 750 «47 Sb 122 i 
. Brassed ee eT Te 127 cs 
S 82 + 48 Sey 7s0) | 49 Te 129 <i 
K 39 + 46 Rb 8 + 48 Cs 133 é 
Ca 40 + 47°5 | Sr 87°5 + 49°5 | Ba 137 
is Jr 395 -+- 48-5 | Ta 138 a 
. . V 137 + 48 W 184 
