DR. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 
.‘385 
They are 
A 
6278-37 
5230-47 
2 
506475 
n 
15923-38 
19113-50 
19738-92 
; 3815-54 
625-42 
The Zeeman patterns of two have been observed by Hartmann. His measures, 
though not perhaps very exact, seem to fit in with the D type, the Zeeman patterns 
of the first two being represented in the notation suggested by me # by 0/5 and 0/6|- 
respectively. These are the patterns for D 21 and D n , so that the set are in the reverse 
order to the usual one, and the relative intensities agree with this. This means that 
calculated as first lines in a D series they have negative values as is the case when the 
first P line is calculated from the S formula. If the limit be taken to be the same as 
for the diffuse, in agreement with its normal separation of 3815"54, the denominator 
of the VD 2 becomes P492977 with a mantissa about "5 below that of D n (2). The 
satellite separation of 625"42 is produced by a satellite difference in the denominators of 
27 S v Starting from these, a linkage of very great length extends, requiring five maps 
to represent them. But it also contains the D n (2) and D 21 (2) lines, has connections 
with other linkages as well as possesses a certain number of false cycles. There must 
therefore be many spurious links. No attempt is made to locate them fully as was 
done in the case of silver, partly because they are more numerous and also because the 
greater difference between modified and normal links renders the entrance of spurious 
values more easy and their detection more uncertain. The whole linkage is given in 
a set of five maps in which the line at which a chain leaves one map or appears at 
another is indicated. As the origin of the set is not certain it is represented by the 
letter X. 
The satellite difference of the three lines forming the starting point is 625"42. Now 
there are a large number of lines with a difference of about 600 which look as if 
related to this in the same way as the F separations depend on the D satellite. It is 
too small to be in analogy with the general case of F series in elements of other 
groups, but a similar diminution is apparent in Cu and Ag. Many of the lines 
showing this difference are connected to v links in a peculiar way. In several cases 
lines n 1 , n 2 differing by 600 have a line at n 1 + v, n x being weaker than % and looking 
like a satellite. The difference between n 2 and n l + v is 14337. Now there are avery 
large number of pairs of lines with this difference, indicating apparently the existence 
of fainter satellites (the n^v) not observed. Where such a difference occurs with a 
line in any of the maps it is indicated by a short broken line—to the right 
when added and to the left when deducted. As one example of the difference 600, 
* ‘Phil. Mag.,’ XXXI. (1916), p. 171. 
3 H 
VOL. CCXVII.-A. 
