272 
SIR J. CONROY ON THE AMOUNT OF LIGHT REFLECTED 
Table XIT. —continued. 
Before repolishing. 
After repolishing. 
Angle of 
incidence. 
Per cent. 
Per cent. 
a-i- 
X2^ 
(x-a- 2 ). 
of light 
^1- 
(x-x,). 
X2. 
(x —Xo). 
of light 
reflected. 
reflected. 
50° 
A. 
162-2 
94-6 
72-5 
184-3 
5-26 
161-3 
95-5 
71-9 
184-9 
5-30 
161-2 
95-6 
72-2 
184-6 
5-38 
161-2 
95-6 
72-4 
184-4 
5-42 
B. 
154-3 
96-8 
68-6 
182-5 
5-56 
158-6 
92-3 
75-6 
175-3 
6-19 
152-8 
98-3 
67-8 
183-3 
5-66 
158-3 
92-6 
76-2 
175-3 
6-29 
152-4 
98-7 
68-3 
182-8 
5-85 
158-3 
92-6 
74-7 
176-2 
6-46 
151-9 
99-2 
67-7 
183-4 
5-81 
157-9 
93-0 
74-5 
176-4 
6-15 
Mean 
5-53 
Mean 
6-27 
56° 34' 
B. 
156-4 
94-7 
77-3 
173-8 
7-25 
155-3 
95-6 
79-7 
171-2 
8-21 
158-7 
92-4 
78-4 
172-7 
6-99 
155-5 
95-4 
79-9 
171-0 
8-22 
159-5 
91-6 
79-2 
171-9 
7-00 
155-2 
95-7 
79-9 
171-0 
8-30 
157-7 
93-4 
79-9 
171-2 
7-64 
154-9 
96-0 
79-4 
171-5 
8-23 
Mean 
7-22 
Mean 
8-24 
O 
O 
A. 
163-1 
93-7 
85-6 
171-2 
8-25 
163-2 
93-6 
84-9 
171-9 
8-02 
161-9 
94-9 
85-3 
171-5 
8-50 
1 
161-8 
95-0 
84-1 
172-7 
8-17 
B. 
154-4 
96-7 
80-2 
170-9 
8-64 
155-1 
95-8 
84-5 
166-4 
9-84 
153-4 
97-7 
80-7 
170-4 
9-10 
154’5 
96-4 
83-5 
167-4* 
9-68 
152-2 
98-9 
79-5 
171-6 
8-88 
1 153-9 
97-0 
83-7 
167-2 
9-95 
151-9 
99-2 
78-3 
172-8 
8-76 
153-7 
97-2 
83-8 
167-1 
10-06 
Mean 
8-54 
Mean 
9-88 
65° 
A. 
166-8 
90-0 
97-0 
159-8 
10-73 
166-8 
90-0 
97-5 
159-3 
10-90 
167-4 
89-4 
98-6 
158-2 
11-08 
168-2 
88-6 
97-8 
159-0 
10-50 
B. 
154-1 
97-0 
87-1 
164^0 
11-18 
156-4 
94-5 
91-9 
159-0 
12-20 
153-3 
97-8 
87-1 
164-0 
11-48 
155-8 
95-1 
91-5 
159-4 
12-28 
152-1 
99-0 
86-6 
I64-5 
11-74 
155-8 
95-1 
91-6 
159-3 
12-32 
151-5 
99-6 
85-9 
165-2 
11-66 
155-4 
95-5 
91-2 
159-7 
12-31 
Mean 
11-16 
Mean 
12-28 
O 
O 
A. 
167-9 
88-9 
109-8 
147-0 
15-64 
167-6 
89-2 
109-8 
147-0 
15-80 
168-0 
88-8 
110-0 
146 8 
15-69 
169-5 
87-3 
111-6 
145-2 
15-67 
