ON COLOUR PHOTOMETRY. 
535 
was made from observations in which the image of the colour patch covered the 
yellow spot and some of the outer part of the retina as well, lies between the curves 
A, B, of fig. 33. 
The curve II in fig. 33 shows the absolute absorption of the rays between the green 
and violet by the yellow spot. Fig. 34 gives the proportionate absorption of the same. 
The colour of the absorbing medium in the yellow spot can be shown on the screen 
by using a template cut out in the way described in Colour Photometry, Part II., 
§ XXXY. 
Table I.—Luminosity Curves. 
I. 
II. 
III. 
IV. 
Y. 
I. 
II. 
III. 
IY. 
Y. 
Scale 
Wave- 
Outside 
yellow 
spot. 
Yellow 
Fovea 
Scale 
W ave- 
Outside 
yellow 
spot. 
Yellow 
Fovea 
number. 
length. 
spot. 
centralis. 
number. 
length. 
spot. 
centralis. 
64 
7217 
32 
4924 
21 
8'5 
6'5 
63 
7082 
. , 
1 
31 
4885 
18-5 
7-0 
5-5 
62 
6957 
1 
2 
2 
30 
4848 
16-5 
5 - 5 
4-0 
61 
6839 
2 
4 
4 
29 
4812 
14-5 
4-7 
3-5 
60 
6728 
3-5 
7 
8 
28 
4776 
13-0 
4-0 
3-0 
59 
6621 
7-5 
12-5 
15-5 
27 
4742 
11-5 
3'5 
2-0 
58 
6520 
12-5 
21 
24 
26 
4707 
10-5 
2-8 
2'4 
57 
6423 
19 
33 
37-5 
25 
4675 
9-4 
2 3 
2-1 
56 
6330 
27-5 
50 
60 
24 
4639 
8-2 
1-82 
1-9 
55 
6242 
35 
65 
77 
23 
4608 
7-3 
1-6 
1-5 
54 
6152 
43 
80 
90 
22 
4578 
6-3 
1-4 
53 
6074 
52-5 
90 
97 
21 
4548 
5-7 
1-2 
52 
5996 
61-0 
96 
100 
20 
4517 
5-0 
1-08 
10 
51 
5219 
71-0 
99 
100 
19 
4488 
4-5 
•94 
50 
5850 
79 0 
100 
98 
18 
4459 
4-0 
•86 
49 
5873 
84 
99 
95 
17 
4437 
3 6 
•78 
48 
4720 
85 
97 
90 
16 
4404 
31 
•70 
47 
5658 
83-5 
92-5 
85 
15 
4377 
2-7 
•62 
•62 
46 
5596 
81-0 
87 
79 
14 
4349 
2-3 
•56 
45 
5538 
77-0 
81 
72'5 
13 
4323 
21 
•50 
44 
548 L 
72-5 
75 
66 
12 
4296 
1-9 
•45 
43 
5427 
68-0 
69 
59 
11 
4271 
1‘65 
•40 
42 
5373 
62-5 
62-5 
51 
10 
4245 
1-4 
•34 
41 
5321 
57 
57 
45 
,9 
4221 
1-2 
•30 
40 
5270 
52 
50 
40 
8 
4197 
1-0 
•26 
39 
5221 
46 
42-5 
32 
7 
4174 
•88 
•22 
38 
5172 
41-5 
36 
27-5 
6 
4151 
'75 
•18 
37 
5128 
37-5 
29-5 
22-0 
5 
4131 
•63 
T6 
36 
5085 
335 
24 
18 
4 
4106 
•50 
•14 
35 
5043 
300 
18-2 
14 
3 
34 
5002 
26-5 
14-2 
10 
2 
33 
4963 
24 
10-5 
8-4 
1 
1 
The following are the scale numbers of the different fiduciary Fraunhofer and 
bright lines :—B 61 *3, Li 597, C 587, D 50‘6, E 39S, b 28, F 30'2, Li (blue) 22'8, 
G 117. 
