370 



DR. W. M. HICKS: A CRITICAL STUDY OF SPECTRAL SERIES. 



also which suggests they are both displaced a suspicion increased by the abnormal 

 increase of the difference shown in the table of denominators between 6 and 7. 

 Provisionally the least change is to suppose the faint line displaced by $ and the 

 strong line by 2<S, as it must, as was noted above, be $ more than the faint line. 



For m = 8 it is cxirious that only one line occurs and no triplets. This suggests 

 that there is no intensification by lateral displacement, and that provisionally it should 

 be taken as normal. The table of difference shows an abnormal increase instead of a 

 decrease, but this may be due to observation errors. If we now calculate the 

 denominators for m = 4, 5, 6, 7, on the above suppositions, displacing the lines for 

 m = 9, 10 also by S, we get 



626133(108) 

 622797 (?) 

 617055 (?) 

 612509(480) 



4'629262 (54) 3129 



4326 

 S'624936 (56) 2139 



4406 

 6'620530 (105) 3475 



4216 

 7'616314(240) 3805 



5256 

 8-611058(728) 



3629 

 9-607429 (643) 



9090 

 10-59833 



Thus the changes indicated by the appearance and arrangement of the lines have 

 brought the denominators and satellites into greater accordance with the general 

 rule. The practical constancy of denominator differences is exhibited also in Tl. The 

 only outstanding irregularity appears to be the satellite difference for m = 5. 

 A lateral displacement of <\ in D ( oo) would decrease the denominator by 743, and 

 increase the difference from 2139 to 2882. It is better to leave the difference 

 without an attempt of explanation at present. 



The second list has been drawn up on this basis, taking = '1 as the errors are 

 somewhat smaller with this value. The denominator for m = 10 is left without 

 further change. Another displacement of 2^ would bring it also 19S below that for 

 m = 9, but the observation errors render any deductions quite unreliable. The 



