232 Intelligence and Miscellaneous Articles. 



Table I. 





A. 



Air 



7 

 8* 



14 

 15 



16 



22 



23* 



24* 



28* 

 30 

 31* 

 32 



37 ! 



38* 1 

 39* j 



45 

 47 





Mixture of benzine and sulphide of carbon. 







B. 



Air 



3* 



3* 

 4 



3* 





16* 

 16* 

 16* 

 16* 



24 

 24 



24^ 

 24 i 



32 

 32 

 32 

 32 



38* 

 38 

 39 

 39* 



54* 



47 





Mixture of benzine and sulphide of carbon. 

 Sulphide of carbon 













Table II. 



43 



H|, 



26J, 



33|. 



These numbers show : — 



1. That, with large angles of incidence, the streaks in the light 

 polarized perpendicular to the incidence-plane, with respect to those 

 in the light polarized parallel to the plane of incidence, are displaced 

 towards the blue, and that in the former another streak occurs in 

 the vicinity of D. 



2. That with the increase of the refraction-index of the surround- 

 ing medium the streaks in the parallel-polarized light undergo dis- 

 placements towards the blue ; while, on the contrary, in the per- 

 pendicularly-polarized light the streaks preserve their position un- 

 changed, or alter it but little. Observation of the streaks in the 

 blue beyond E is attended with great difficulties, as is the entire 

 investigation, through the breadth of the streaks and the impossi- 

 bility of obtaining perfectly reflecting surfaces. 



A comparison of the streaks obtained in the transmitted and in 

 the reflected light shows that never do two of such streaks cover 

 one another, and that neither do the former he each in the middle 

 between two of the latter. 



As to change of position of the streaks with the angle of inci- 

 dence, it resulted that in the light polarized parallel to the plane of 

 incidence, and likewise in natural light, the position was as good as 

 independent of the angle of incidence ; but in the light polarized 

 perpendicular to that plane the streaks have, up to a certain angle 

 of incidence, which amounted to 



Air. 



58|°, 



Benzine. 



about 52 c 



Sulphide of carbon, 

 about 52°, 



the same position as in the parallel-polarized, and then, with a 

 small alteration of the incidence-angle, suddenly suffer a displace- 

 ment characterized by the appearance of the streak the details of 



