:;,;. DR. W. M. HICKS: A CKITICAL STUDY OF SPECTRAL SElilKS. 



errors than the satellites of the first see remark in the table. If the latter be 

 calculated from them, using the accurate value of l = 388 '90, the differences come 

 out to be 525, 369 and 456, 399, quite reversing the order of magnitude for the first 

 satellite of the lines for m = 2, 3, and, moreover, their differences are larger than S } . 

 The differences best consonant with the measures using the derived values from Da- 

 are 13<5, = 503 and IOS 1 = 388, giving a ratio of 1'30. Those entered in the table, 

 however, are 15^ = 581, 9(5, = 348, both within the limits of observation, and adopted 

 because they give a ratio 5 : 3, the same as the other elements of Group 2. The 

 satellite separations for m = 3 may be the same as the latter within limits, but not 

 necessarily so. 



The order differences do not work in well with the above when = 0. If, however, 

 be put = 2 '2 5, they fall into line with extreme accuracy, as shown in the table. 

 It is of interest to notice that the differences are multiples of S v = 6^, which seems to 

 be specially associated with zinc. 



The denominators for m = 6, 7 are now G'915855 (4068) and 7'924179 (11320), 

 showing too large a rise to be due to error observations. Treated as collaterals 

 with -2J, and -3^ they become 6'909593, 7'910070, clearly near the probable 

 limit. 



Judging from analogy, we should not expect the differences to stop at 4^ 6 . The 

 series (7, 6, 4) <S 6 would probably be continued, but the errors are too large to settle 

 the question. If the series were continued, e.g., by 2S e , 0, the denominators would be 

 6-910288-G95 and 7'910288-218. But the best agreement is to take them as they 

 are. This would also be in analogy with Ca, in which D ( oo ) begins to change when 

 VD stops changing. 



Cd. 



In the table is taken '25 above S(o>), as given in [II.]. It is seen that the 

 arrangement fits in with great accuracy, and as ^ is as large as 114, the arrangement 

 may be considered to have some weight. The denominators calculated from the 

 D, and D 3 lines (more accurately determined) do not agree with the observed D t 

 satellites. It would therefore appear that the second and third members of the 

 triplets may also be subject to special displacements. Here, for instance, the lines of 

 order 3 are brought into line if the observed VD 21 (3) is VD 12 (3) (-5,). The value of 

 D,,(4), calculated from K.R.'s D 31 (4), cannot be the normal one, even when his 

 extreme possible error is allowed. This shows again that VD 31 (4) must be displaced 

 from VD 13 (4), in this case by lOc?,. 



^ The denominator for m = 6 shows the sudden large rise after a slow change which 



Zu also exhibits, but it cannot be explained, as in that case, by treating it as a 



llateral due to a modification of D ( oo) alone. The closest collateral of this type 



due to J, and this changes D (oo) by 5'66 producing in the denominator 



a change too far in the opposite direction. In fact it becomes 6'912000, 3471 below 



