On Polarization of Light by Refraction. 235 
. oe in tnclina ed 
Angles /Angl 
Sas 5 Seg of| Plane ot Pole Plane of Polari- a Quantity 
| cidence, tion, Reflected Refracte ected, 
— a. ight, ight, R. 
oO i ° f ° i i 
» 010, 9 45 0 45 0 43.23 
2 0} 1 188) 44 57 45 0.7 43.26 
10° 0 | 6 32] 43 51 45 3 43.39 
20 0 {12 58 40 13 45 13 43.41 
25 0/16. 5 37 21 45 21 43.64 
30. 0/19 84 33 40 45 3l 44.78 
35 0 |22 29.8 45 44 46.33 
40 O (24 56/ 23 41 46 0 49.10 
45° 0 (27 373, 17 224 46 20 53.66 
50 0 |30 9 10 18 46 45 61.36 
196 45 33 15 U6 47 29 79.5 
160 O 34 36 5 4 47 544 93.31 
65 0 |36 28 12 45 48 42 124.86 
70 0/388 2/ 18 32 | 49 28 | 162.67 
75 O |39 18 26 52 50 55 257.56 
78 0 39 54/ 3044 | 51 48 | 329.95 
|78 7 139 55 | 30 53 51 50 20 
79 0/40 4/| 31 59 52 7 359.27 
80 40 |40 13 | 33 13 52 27% | 391.7 
82. 4/40 35 | 36 22 53. 264 | 499.44 
84 0 40 42} 38 53 57 560,32 
185 0 |40 47| 39 12 54 22 | 616.28 
85 50340 50%) 40 12 54 44 666.44 
86 0 40 51 40 22,7,, 54 48 676.26 
87 0 40 54 41 55 16 744.11 
88 0 |40 573| 41 23 55 43 819.9 
189 0 |40 58 43 51 56 14 904.81 
90 0 40 58 45 0 56 29 '1000. 
_ It is obvious from a consideration of the principle of the formula 
for reflected light, that the quantity of polarized light jesotiing at 0° 
because the force which polarizes it is there a minimum. At the 
‘Maximum polarizing angle, Q is ouly 79° because the glass is inca- 
pable of reflecting more light at that angle, otherwise more would 
have been polarized. The value of Q then rises to its maximum at 
78° 7’, and descends to its minimum at 90°; but the polarizing 
force has not increased from 56° 45’ to 78° 7 as the value of 9’ 
shows. It is only the quantity of reflected light that has increased, 
Which occasions a greater quantity of light to disappear from the 
_ ©xtraordinary image of the analysing rhomb. ae 
