Reflexion of Light from Iceland Spar. 



257 



light of a lamp reflected from the surface immersed in water.* With 

 a view to a comparison of my own work with his results, a second 

 Argand burner was placed close to the former. The brass table was 

 undamped and rotated till the face of the crystal was in such a posi- 

 tion that the incident light was reflected to the opposite side of the 

 table to that on which the elliptic analyser was placed. The reflected 

 light was observed with a simple analyser consisting of a Nicol, the 

 azimuth of which could be determined by means of a divided circle 

 and verniers to 3'. 



The observations made with the elliptic and simple analysers are 

 given in Tables IX and X respectively. 



Table IX. — Second Series of Observations with the same Polished 



Face (Elliptic Analyser). 





r. 





E. 



I. 



136 



•891° 



43 "732° 



133 -320° 



42-164° 



87*'742° 



136 



•825 



43-817 



133 -591 



42-212 



87 -901 



136 



•779 



43-557 



133 555 



42 -200 



87 -877 



136 



•940 



43-311 



133 -431 



42 -066 



87 -748 



136 



•980 



43 345 



133 -149 



41-840 



87 -494 



136 



•410 



43 -105 



133 -307 



42 -095 



87 -701 



137 



070 



43 -845 



133 -431 



41 '792 



87-611 



136 



•903 



43 -452 



133 '137 



41-769 



87 -453 



137 



•131 



43-782 



133 085 



41 -657 



87 -371 



136 



•878 



43 -476 



133 -294 



41-945 



87 -619 



137 



•406 



43 -946 



133 -277 



41-966 



87 -621 



136 



•566 



43-360 



133 -220 



42 -025 



87-622 



136 



•767 



43 -503 



133 '427 



41 -762 



87-595 



136 



974 



43-524 



133-591 



42 -011 



87 -801 



Table X. — Second Series of Observations with the same Polished 

 Face (Simple Analyser). 





Mean of ten 

 readings of 

 1st vernier. 



Mean of ten 

 readings of 

 2nd vernier. 











356 5^0 



176 13-8 





355 57-4 



176 6 1 





355 59-4 



176 8 -2 





356 2-9 



176 12 1 





355 59-4 



176 8-6 



Mean . . 



356 0-82 

 Mean of 100 = 



176 9 -76 

 = 266° 5 -3'. 



VOL. XLll. 



* ' Boy. Soc. Proc.,' Feb., 1886. 



T 



