

,;. 



M NICKS: A CRITICAL STUDY OF SPECTRAL SEKIKS. 



,1,.,,,,,,. tin- *kf of the group, the sub-groups would be based on (2n + l),\ :.ml 

 (2n + 2) t, This would leave J, and 2J, for group 0. He, as is seen, may IK- cither. 



The foregoing evidence is, I think, conclusive that the atomic weight terms are 

 multiples of a quantity very close to one quarter of 361'8w. Before attempting .... 

 existing knowledge to obtain a closer value to this quantity, it will be desirable to 

 consider certain other ways in which the atomic weight plays a part, and which will 

 provide further data for its more exact determination. As it will be convenient to 

 have a name for these quantities which seem to have a real existence, the word " oun " 



(u>v)* is suggested. 



The curious irregularities in the value of the oun noticeable in the elements of the 

 2nd group in connection with the separate A! and A 2 values, whilst the values found 

 from A, + A 2 are normal is worth examining in closer detail. The values of V i + v a 

 given in the table are deduced from the sums of v lt v y , each determined independently 

 by least squares from the best observations. If the values of i + v a are determined 

 directly the values are slightly different, which is natural as they are found from 

 selected pairs. The old values and the values thus found are collected here, and with 

 them the values of S/iv*. 





New . 

 Old . 



New . 

 Old . 



New . 

 Old 



Mg. 

 6079(362-36) 



Ca. 



158'Gl (361-45) 



St. 



581-21(361-60) 



6079(362-36) 157'98 (361'39) 58T28 (361*64) 



Ba. Ra. Zn. 



1248'85(361-56) .2882'26(361 I 84) 578'998 (362'23) 



1248-54(361-48) 2882'26 (361'84) 578'998 (362'23) 



Cd. Eu. Hg. 



1712-84(362-41) 2634'5(36r94) 6397'53 (362'46) 



171274(362-39) 2634'5 (361'94) 6397'66 (362'57) 



It will be shown later that spectroscopically Mg belongs rather to the Zn sub-group 

 than to the Ca. The same tendency is exhibited here. The more probable values of 

 fi + v-j, have brought the oun more closely to equality with 36T60W 2 for the Ca 

 sub-group, and with 362"4 for the Mg and the Zn sub-group. The value of v l for Eu 

 may be 2633*5 instead of 2630'5, and if so, its value of the oun would come to 

 362*34. If the variations in the value of the oun had been more irregularly 

 distributed, it might have been natural to assign the variations (small as they are) to 

 errors in the value of the atomic weight. But this does not seem justified unless 

 there are chemical reasons whereby atomic weights in any particular group have a 

 liability to be all over-estimated or all under-estimated. In view of the latter 



' The pronunciation of oun will be the same in the chief European languages. 



