44 
mi. W. ^r. MICKS: A CEITTCAL STUDY OF SPECTRAL SERIES. 
the ^■alues o(‘the atomic volumes "iveii hy T\.TcriARDS and Brink,* lead to values of 
D/2r, o'iven hy the first line of figures in the tollowinfic table :— 
Na. 
K. 
Rl). 
Cs. 
•002466 
•002578 
•002615 
•002541 
•002761 
•002762 
•002710 
•002640 
the values for (fs heiuo; very uncertain. Idie values show first a gradual rise with 
atomic weight, and then a fall. The fall of melting-poiiit, i.e., increase of the 
measured atomic volume on nearing the melting-point, wo\dd explain a fall in the 
ratio shown hy ('S. The first rise must he explained by another cause. Now, it was 
pointed old in Part 1. that the ]n'o]iortionality (a/^) Avas closer if the denominators 
Avere measured from about 'DSC) instead of 1, the numhei’ ’hSl) having appeared in 
quite another relation. In other Avords, a number about '014 shoidd be added to the 
fractional part of the denominator. Tf'this he dcAue, the results obtained are shoAvn 
in the second line of figures in the ahoAm table. In this case, the exactness of the 
ratio is striking, the fall in Cs being probably due to error of formula as well as 
closeness of melting-point. We may take the ratios as A’ery close to ■(HT2740. This 
is for the alkali elements. It iioaa' remains to see Avhether any similar relationships 
hold for the elements here considered. 
Taking first the Zn sub-group, the fcAllowing values are obtained from Table I. for 
the values of the fractional parts (if the denominators of(l), i.e., of V8 (l) 
Zn . . ■•227000 ; Cd . . •282050 ; Eu . . 
The densities at (Ardinary temperature, as given 
respectively 
•244080 ; Hg . . -241297. 
in Landolt and Bornstein, are 
Zn . . 7-01 ; (1(1 
8-05 ; E 
u 
llg 
10-55 ; 
AAh.ieh giA^e for the atomic Aolumes at ordmaiw temperatures 
9-00, uroo, ?, i 4 - 7 (;. 
It IS clear, at a glance, that the aboA'e denominators cannot be ju'oporfional tci the 
atomic Aadinnes, but it is easy to sIioav that m Zn, CM, and Tig theA" ai’e respectiA'ely 
proportional to 9c, 8c, and Oc. ■ In fact, the ratios to these come out to 
•002715 X 9c, -002715 X 8c, • -002725 xGc. 
The ratios sIioav 
tlie alkalies AA'heii 
a remarkable agreement Avith themselA’es and also with those of 
referred to 98(). The practically exact equalitj^ of the aboA'C 
* ‘Jour. Amer, Chem. Soc.,’ 1907, p. 117 
