ON COLOUR PHOTOMETRY. 
565 
Table XII.—B. C/s Curves. 
I. 
II. 
III. 
1Y. 
V. 
YI. 
Scale 
Adopted 
Persistency 
Luminosity 
of original 
beam. 
Absolute 
W ave- 
reading in 
curve, 
luminosity of 
number. 
length. 
hundred 
12,500 
extinction 
thousandths. 
readings in V. 
111. and V. 
61 
6839 
7,500 
1-6 
60 
6728 
5,500 
23 
*5 
27-5 
59 
6622 
4,000 
3-1 
i 
40 
58 
6520 
2,800 
4-5 
2 
56 
57 
6423 
2,000 
6-2 
4 
80 
56 
6330 
1,500 
8-3 
6 
90 
55 
6242 
1,150 
10-8 
8 
92 
54 
6152 
950 
131 
11-5 
1092 
53 
6074 
750 
16-6 
16 
120 
52 
5996 
580 
21-6 
21-5 
125 
51 
5919 
430 
29 
28-5 
122-5 
50 
5850 
350 
36 
37 
129-5 
49 
5783 
275 
45-5 
47 
129-2 
48 
5720 
215 
58 
60 
129 
47 
5658 
170 
73 4 
76 
129-2 
46 
5596 
140 
89-3 
92 
129 
45 
5538 
125 
100 
98 
122-5 
44 
5481 
125 
100 
100 
125 
43 
5427 
130 
961 
97 
126 
42 
5373 
150 
83 
85 
127-5 
41 
5321 
180 
69-4 
65 
117 
40 
5270 
215 
59 
45 
96-7 
39 
5221 
250 
50 
30 
75 
38 
5172 
290 
43 
215 
72-3 
37 
5128 
335 
37 
16 
53-6 
36 
5055 
380 
33 
115 
43-7 
34 
5002 
500 
25 
7 
35 
32 
4994 
650 
19 
4 
26 
30 
4848 
850 
14 
2-5 
23-3 
28 
4776 
1,100 
11-4 
2 
22 
26 
4707 
1,500 
8 3 
1-5 
22 
24 
4639 
2,000 
6-2 
1 
20 
22 
4578 
2,700 
4-6 
5 
13-5 
18 
4459 
4,750 
14 
4349 
7,500 
10 
4245 
11,000 
