548 
CAPTAIN W. DE W. ABNEY AND MAJOR-GENERAL E. R. FESTING 
Table IV.—Extinction by Whole Eye. 
I. 
II 
1 
III. 
IV. 
V. 
VI. 
Scale 
number. 
Wave¬ 
length. 
E. 
Reduction of 
original 
luminosity 
in millionths 
to cause 
extinction. 
L. 
Luminosity 
of 
original beam. 
E x L 
160 ' 
Persistency curve 
650 
E 
(Maximum —100). 
38 
5172 
6-9 
41-5 
2-86 
94-2 
37 
5128 
7-1 
37-5 
2-66 
91-6 
36 
5085 
7'4 
335 
2-48 
87-8 
35 
5043 
77 
30-0 
231 
84-4 
34 
5002 
8-0 
26-5 
2-12 
81-2 
33 
4963 
8-4 
24-0 
2-02 
77-5 
32 
4924 
8-8 
21-0 
1-85 
73-8 
31 
4885 
9-4 
18-5 
1-74 
69-2 
30 
4848 
10-0 
16-5 
1-65 
65-0 
29 
4812 
107 
14-5 
1-55 
60-6 
28 
4776 
11-5 
13-0 
1-49 
56 - 5 
27 
4742 
13-0 
11-5 
1-49 
50-0 
26 
4707 
14-5 
10-5 
1-52 
44-8 
24 
4639 
18-5 
8-2 
1-52 
341 
22 
4578 
23-0 
6-3 
1-45 
28-3 
20 
4517 
30-0 
5-0 
1-50 
21-7 
18 
4459 
39-0 
4-0 
1-56 
16-7 
16 
4404 
51 
31 
1-59 
12-3 
14 
4349 
66 
23 
1-52 
9-85 
12 
4296 
80 
1-9 
1-52 
8-12 
10 
4245 
110 
1-4 
1-54 
591 
8 
4197 
154 
1-0 
1-54 
4-22 
6 
4151 
204 
•75 
1-54 
318 
4 
4106 
307 
•5 
1-54 
211 
2 
4063 
513 
•3 
1-54 
1-26 
0 
4020 
770 
•2 
1-54 
•84 
