254 Mr. S. S. Richardson on Magnetic Rotary 



For the natural dispersion in this liquid Walter's * values 

 have been taken (to four decimal places) and appear to be 

 fairly represented by a mean period X = *2370, the formula 

 I obtain being : 



-1 = -95422 + '66659 



X 2 



X 2 - -05617' 



XX 104. 



n (obs.). 



n (calc). 



Diff. 



•7621 



1-6405 



1-6408 



4-3 



•6884 



1-6464 



16463 



-1 



•6563 



1-6495 



16495 







•5893 



1-6582 



16581 



-1 



■5270 



1-6705 



1 6703 



-2 



•4861 



1-6819 



1-6819 







•4341 



1-7041 



1-7041 







•4308 



1-7059 



1-7059 







•4102 



1-7185 



1-7190 



4-5 



•3970 



1-7289 



1-7291 



4-2 



Carbon Bisulpliide. 



The liquid used was purified by allowing it to stand in 

 contact with mercuric chloride for several weeks, with sub- 

 sequent repeated distillation over mercury. The product 

 was almost odourless. The values of n were deduced from 

 those of van der Willigen. In this case the observations 

 were confined to the visible spectrum. t = 20°. 



Obs. 



xxio 4 . 



£xio 6 . 



*»20- 



4>xio 14 . 



a 



•6708 



14-68 



1-6182 



6-604 



b 



•5893 



j 19-90 



1-6291 



6-912 



c 



•4958 



30-71 



1-6508 



7-550 



d 



•4326 



44-59 



1-6775 



8-344 



e 



•4144 



50-50 



1-6885 



8-653 



/ 



•4046 



54-14 



1-6952 



8-863 



The first three observations were obtained by the visual 

 method, the latter three photographically. 



* Ann. d. Phys. 1891. 



