Structure of the Line-Spectra of the Chemical Elements. 331 



The dummy tubes had thus actually lost slightly more in 

 alkalinity than the tubes through which the air had passed. 

 This loss is about equal to what would be caused by the 

 absorption of the carbonic acid contained in 6 litres of pure 

 air. 



It follows from this and the other experiments just referred 

 to that the error with the tube method may be considerable, 

 at least in experiments of not more than two or three hours' 

 duration. 



XXXIV. On the Structure of the Line-Spectra of the Chemical 

 Elements. By J. R. Rydberg, Ph.D., Docent at the 

 University of Lund!' 



(Preliminary Notice.) 



THE researches, the most important results of which are 

 given in the following pages, will be published 

 with full details in the Svenska VetensJc.-Akad. Handlingar 

 Stockholm. They have extended hitherto only to the 

 elements which belong to the groups I., II., III. of the 

 periodical system ; there is, however, no reason to doubt but 

 that the laws I have found can be applied in the same way 

 to all elements. 



In my calculations I have made use of the wave-numbers (n), 

 instead of the wave-lengths (A.) ; n=10 s . X -1 , if X be expressed 

 in Angstrom's units. As will be seen, these numbers will 

 determine the number of waves on lcentim. in air (760 millim., 

 16° C. according to Angstrom), and are proportional, within 

 the limits of the errors of observation, to the numbers of 

 vibrations. 



1. The " long" lines of the spectra form doublets or triplets, 

 in which the difference (v) of wave-numbers of their correspond- 

 ing components is a constant for each element. 



This law, found independently by the author, has already 

 been announced by Mr. Hartley for Mg, Zn, Cd. The values 

 of the constant differences (v) vary from v = 3*l in the spec- 

 trum of Be to v=7784"2 in the spectrum of Tl. In each 

 group of elements the value of v increases in a somewhat 

 quicker proportion than the square of the atomic weight. 

 For instance : — 



* Communicated by the Author. 



