AND TRANSMITTED BY CERTAIN KINDS OF GLASS. 
2G7 
the formula K = 
■Xg {X — X^) I ^ 
(x — x„) \ 
These values, and others obtained from similar sets 
of measurements, are contained in Table VIII. 
Table VIII. 
Crown Glass. 
Angle 
of incidence. 
®i- 
{x - .r,). 
{X - X^). 
Per cent, of 
incident light 
reflected. 
A. 6° 17' 
168-7 
88-1 
68-6 
188-2 
3-62 
167-8 
89-0 
68-7 
188-1 
3 75 
167-1 
89-7 
68-3 
188-5 
3-78 
166-9 
89-9 
68-1 
188-7 
3-78 
6° 17' 
171-5 
85-3 
71-7 
185-1 
.3-71 
173-6 
83-2 
74-5 
182-3 
3-84 
174-3 
8-2-5 
74-0 
182-8 
3-67 
175-6 
81-2 
76-4 
180-4 
3-83 
B. 6° 47' 
156-1 
95-2 
61-3 
190-0 
3-87 
156-6 
94-7 
61-4 
189-9 
3-82 
156-0 
95-3 
61-6 
189-7 
393 
155-5 
95-8 
61-3 
190-0 
3-95 
7° 30' 
158-4 
92-5 
62-2 
188-7 
3-70 
157-8 
93-1 
61-7 
189-2 
3-70 
157-8 
93-1 
62-4 
188-5 
3-81 
157-7 
93-2 
62-3 
188-6 
3-81 
157-5 
93-4 
61-8 
189-1 
3-76 
Mean 
3-78 
Similar measurements were made with the flint glass wedge. The results are given 
in Table IX. 
Table IX. 
Flint Glass. 
Angle of 
incidence. 
a-1. 
(.r - .r-,). 
a-2. 
(x — .Tj). 
Per cent, of 
incident light 
reflected. 
10° 
156-2 
94-7 
68-2 
182-7 
5-12 
155-9 
95-0 
67-8 
183-1 
5-09 
155-1 
95-8 
68-7 
182-2 
5-42 
155-6 
95-3 
69-1 
181-8 
5-42 
10° 
157-6 
93-3 
68-9 
• 182-0 
5-02 
157-6 
93-3 
C9-4 
181-5 
5-12 
157-2 
93-7 
69-4 
181-5 
5-20 
jMean 
5-20 
2 M 2 
