M. A. Berlin on Circular Magnetic Polarization. 497 



1 . Eicper intent with sulphuret of carbon, 

 e=4ri d-11. 



The rotations compared being here more considerable, I 

 have deduced the value of r from the equation 



ri"+r- 



;2-06, 



whence 



r=0'97587. 



The numbers compared with the experiments in the pre- 

 ceding tables have all been calculated with this value of r. 



The general formula also furnishes us with another series 

 of proofs. If we vary merely the thickness of the flint-glass 

 by placing it in contact with one of the coils, we shall obtain 

 as the relation of two rotations z and 2', produced by two 

 thicknesses e and ef, 



z ~ Kl—r") 



'1 + 



.1+;^ 



FhiL Mag. S. 3. No. 232. Suppl. Vol. 34. 



2K 



