260 



Mr. W. Sutherland on the 



v=63*8 (3, 12, 26) + 31*6 where 26 takes the place of the 

 normal 28. This finishes the discussion of the first of our 

 two principles supplementary to Rydberg's laws. 



The second principle is derived from a study of the spectral 

 parameters of the elements, which we proceed to tabulate. 

 The values for H are Rydberg's (Astrophysical Journ. vL 

 1897) ; for He, BalmerV(Wied. Ann. lx.) / for 0, S, and Se 

 Runge&Paschen's (Wied.^nn.lxi.) ; andforthe other elements 

 they are the results of my own computations of the observa- 

 tions of Kayser & Runge with the aid of their selectioD of 

 serial lines, and also Rydberg's (Wied. Ann. xli., xliii., xlviii.,, 

 1., Hi.). In my computations I have not assumed B to be 

 absolutely constant at its value 109675 for hydrogen as 

 Rydberg does ; but with other computers of spectral para- 

 meters I have obtained a value for B independently for each 

 element. For details the reader should consult the above 

 references. 



Table III. 





n . 





B. 



li. 





Princ. 



Usual. 



Princ. 



Usual. 



Princ. 



Diffuse. 



Sharp. 



H ... 



48744 



27419 



109675 



109675 



1-0 



00 



•5 



He... 



38471 



29238 

 29229 



110470 



109900 

 109520 



1-94269 



1-99939 



1-697 



He... 



32043 



27184 

 27181 



109820 



109930 

 109460 



.201195 



2-0002 



1-8529 



Li ... 



43506 



28600 



110480 



109900 



1965 



00 



1-597 



Na... 



41453 



24490 



107900 



110600 



21 



00 



1-66 



K ... 



35009 



21966 



107700 



111170 D. 



108960 S. 



2-233 



•80 



1-80 



Eb... 



33707 



20861 



108600 



108800 



2-30 





1-667 



Cs ... 



31372 



19721 



104570 

 Diffuse. 



113950 

 Sharp. 



2-30 





1-60 



Mg... 





39730 



107250 



104320 





•80 



•26 



Ca ... 





33890 



103500 



100000 





o-o 



•380 



Sr ... 





30860 



96910 



96232 





00 



•40 



Ba ... 





24860 





89540 







•411 



Zn ... 





42880 



110100 



110100 





•912 



•186 



Cd... 





40660 



105500 



105500 





•848 



•26 



Hg... 





4006S 



103600 



103600 





•848 



•196 



Al ... 





48040 



100600 



100600 





00 



•101 



In ... 





44430 



113900 



105800 





•88 



•20 



Tl ... 





41500 



110800 



107800 





•90 



•198 



... 



23208 



23201 



110396 



109011 





•02148 



•24127 



S ... 





20078 



108868 







•07945 





Se ... 





19287 



111964 







•00556 





[N.B. — Where the integral part of jw is not known the fractional part only 

 is given, or, in the absence of a fractional part, it is returned as 0.] 



