High-Frequency Spectra of the Elements. 



793 



(v being the frequency of the radiation, v Rydberg's general 

 •constant, and N the atomic number), which is in such good 

 agreement with the values for Al-Zn, does not hold good 



throughout the series of the elements. 



In fig. 4 the values 



Fig. 4. 



1-9 

















1 ! i 



















1 — 







! 





















































































































i 



































I 













! 



























1-4 



1-3 





I 



















































! 











y 















— 





— 

























X 































































10 

 0-9 

 0-8 

















































































































*c 



s~ 









_J 





































^ 



fr 





























0-6 











X 



# 







































A 



f 



' 















1 



























S 



;- 





! 





































IV? 



k' 











1 































! | 













1 



























1 



13 '5 17 IS cl c'3 25 V 29 5.1 33 35 37 Z9 4! 43 43 47 49 51 53 55 57 59 61 — ' 



found by Moseley for the elements Y-Ag are represented 

 instead of mine, and, as seen, the curve shows the same 

 tendency as that found by me. Possibly the formula 



n\ = 2d . sin a 



is not quite accurate for the small angles dealt with, d being- 

 subject to a correction for these angles. This supposition 

 might be examined by measuring the angles in the higher 

 orders, but for this the method used here was not convenient. 

 With a silver target an exposure was made without the 

 zincblende screen and with the slits only 0*2 mm. in width, 

 in order to find out if the silver lines are double, as has been 

 shown for rhodium by Bragg *, with an ionization method, 

 and for nickel by W. F. Ravvlinson f by a photographic 

 method. Indeed, two different a- lines appeared on the 

 plate, but on further examination even the band produced 

 by the direct rays, showed on a less dark background two 

 darker lines, closely situated, as well as three feebler ones. 

 A supposition that these lines might be lines of interference 



* Phil. Mag. xxvii. 



t Phil. Mag. Aug. 1914, p. 274. 



Pkil. Mag. S. 6. Vol. 28. No. 168. Dec. 1914. 



3F 



