Dr. Brewster on the Polarisation of Light. 223 • 
Table shewing the Angles at ivhich Light is polarised by oblique 
Refraction, through different numbers oj Plates. 
Number of Plates 
ill each Parcel. 
Angles of Incidence 
at which Light is 
polarised. 
Angles of Incidence 
at which Light is 
polarised. 
Differences between 
the calculated and 
observed Angles. 
By Calculation. 
By Experiment. 
1 
88° 
38' 
2 
87 
16 
3 
85 . 
54 
4 
84 
32 
6 
81 
50 
8 
79 
11 
78“ 
52'* 
0 
19' -- 
10 
76 
33 
76 
24 
0 
9 — 
12 
74 
0 
74 
2 
0 
2 + 
14 
7 i 
30 
72 
15 
0 
45 + 
16' 
^■9 
4 
69 
40 
0 
36 + 
18 
66 
43 
66 
43 
0 
0 
21 
63 
21 
^3 
39 
0 
18 + 
24 
60 
8 
61 
0 
0 
52 + 
27 
57 
10 
56 
58 
0 
12 — 
29 
55 
16 
54 
50 
0 
26 — 
31 
53 
28 
53 
16 
0 
12 — 
33 
51 
44 
51 
0 
0 
44 — 
35 
50 
5 
50 
03 
0 
18 + 
39 
47 
1 
46 
50 
0 
11 — 
41 
45 
35 
45 
49 
0 
14 + 
44 
43 
34 
44 
0 
0 
26 + 
47 
41 
41 
42 
0 
0 
19 + 
100 
22 
42 
200 
1 1 
49 
* This result was 
obtained by a parcel 
500 
4 
47 
of plates 
of parallel glass. 
1000 
2 
24 
2000 
1 
1 2 
4000 
0 
36 
14000 
0 
1 
8,640,000 
0 
0 1'' 
