BLACKWELL. — DISPERSION IN ELECTRIC DOUBLE REFRACTION. 651 



TABLE I. 

 Electric Double Refraction of Carbon Bisulphide 



Absolute values are obtained in terms of (/u e — fj.^) by multiplying the above 

 values by 7.04 ■ 10 -7 , the observed absolute value of the double refraction at 24°.0 

 and A = 5890. 



Observations were terminated in the violet by the absorption of the 

 liquid. The sharpness with which absorption begins is shown in the 

 photograph of the iron spectrum taken through 96 cm. of carbon 

 bisulphide. (Plate, Figure A.) At wave-length 4180 the spectrum 

 was still bright; at 4144 very faint. Within 50 Angstrom units 

 change of wave-length the light was practically cut off. In the follow- 

 ing observations on dispersion the light passed through 109 cm. of 

 liquid, and measurements of the photographs could not be made on 



