PHYSICS: ANSLOW AND HOWELL 
409 
only. Therefore the sons of the daughters, or sisters, of successful naval 
fighters are more apt to be successful naval men than are the sons or 
the sons' sons of fighters, unless (as often happens) these fighting fathers 
marry daughters or sisters of naval men. 
Hyperkinesis in either parent gives a favorable prognosis for naval suc- 
cess in the son: but some of the very best naval fighters have been hy^o- 
kinetics and, under modern conditions of naval warfare, this type is 
less handicapped than formerly. 
Four typical family pedigrees are annexed. 
List of the 14 naval officers utilized in this study: — 
Bainbridge (U. S.), Barney (U. S.), Gushing (U. S.), Cochrane (Eng.), 
Paul- Jones (U. S.), Lawrence (U. S.), MacDonough (U. S.), Keppel 
(Eng.),Mafiitt (U. S.), Morris (U. S.), Perkins (U. S.), Porter (U. S.), 
Battnall (U. S.), Wolsely (Eng.). 
THE TRIPLET SERIES OF RADIUM 
By Gladys A. Anslow and Janet T. Howell 
DEPARTMENT OF PHYSICS. SMITH COLLEGE 
Communicated by G. E. Hale, May 2, 1917 
Many attempts have been made to establish a relationship between 
the spectra of elements and their atomic weights. Referring to the 
doublets which occur in the first and second subordinate series, Runge 
and Precht^ stated the following law. ^'In each group of chemically 
related elements the atomic weight varies as some power of the distance 
apart of a pair." They applied this law to the group of alkaline earths, 
and when they plotted the logarithm of the frequency difference of the 
pair series in each element agaiast the logarithm of the atomic weight 
they obtained a straight line which gave by extrapolatioQ an atomic 
weight of 257.8 for radium. As this was too large a value Ives and Stuhl- 
mann^ replotted the results of Runge and Precht using the atomic num- 
ber in place of the atomic weight. Although their results were in 
general more consistent the atomic number found for radium was 96 
instead of 88. 
Now the elements of the second group of the periodic table are char- 
acterized by the presence of both doublet and triplet series of the prin- 
cipal, first, and second subordinate types. On plotting the logarithms 
of the atomic numbers against the logarithms of the frequency differences 
between the extreme members of the triplets we found that alternate 
elements fall on straight lines as in figure 1. Therefore the triplets of 
radium should fall on a line with calcium, strontium, and barium. The 
