Dispersion in Relation to the Electron Theory. 249 



xxio\ 



<p (obs.). 



<p (calc). 



Diff. 



•5893 



4-574 



4574 



(ref.) 



•4529 



5-137 



5137 







'4046 



5-567 



5566 



-1 



•3631 



6-186 



6-187 



+ 1 



•3306 



7-014 



7-013 



-1 



•3100 



7-846 



7-847 



+ 1 



The natural dispersion in benzene has been measured by 

 Simon * in the visible and ultraviolet, and by Rubens in the 

 infra-red. I find the results well represented by formula 

 (3), taking the mean effective dispersional period at '1815 /uu, 

 anda! = -62871, a = -55695, c='0017. Thus: 



• 62871X2 '0017 X«. 



n 2 -l = -55695 + 



The differences between the 

 are given in the table below. 



\ 2 -V 



observed 



and calculated values 



Obs. 



xxio 4 . 



n (obs.). 



n (calc). 



Diff. 



(Author). 



Diff. 



(Martens). 





•2837 



1-6190 



1-6190 













•2881 



1-6120 



1-6122 



+ 2 



+ 5 





•2981 



1-5983 



1-5986 



+3 



+ 10 





•3404 



1-5603 



1-5605 



+2 



+12 





•3467 



1-5564 



1-5565 



+1 



+ 11 





•3613 



1-5485 



1-5484 



-1 



+8 





•4341 



1-5229 



1-5227 



-2 







o 



•4678 



1-5158 



1-5155 



-3 



-3 



(72 



•4800 



1-5137 



1-5136 



-1 



—5 





•4861 



1-5125 



1-5123 



_2 



-3 





•5086 



1-5094 



1-5090 



-4 



-7 





•5349 



1-5060 



1-5056 



-4 



-8 





•5893 



1-5005 



1-5003 



_2 



-8 





•6563 



1-4959 



1-4957 



_2 



-11 





•7682 



1-4907 



1-4905 



_2 



-12 





•810 



1-4890 



1-4892 



+ 2 



-8 





•864 



1-4874 



1-4873 



-1 



-8 





•926 



1-4859 



1-4864 



+5 



— 7 



aj 



•997 



1-4848 



1-4851 



+3 



-8 





1-080 



1-4834 



1-4839 



+5 



-6 





1-178 



1-4822 



1-4826 



+ 4 



-5 



M 



1-297 



1-4813 



1-4817 



+4 



-6 





1-439 



1-4801 



1-4806 



+5 



_2 





1-621 



1-4792 



1-4796 



+4 



-1 





1-850 



1-4784 



1-4785 



+ 1 







Ann. d. Phys. (53) p. 542 (1894). 



