ON COLOUR PHOTOMETRY. 
439 
G’s observations. 
Original 
readings. 
Reduced 
readings. 
Scale reading. 
Intensity. 
Scale reading. 
Intensity. 
43Y0 
9-0 
43-70 
1-5 
43-80 
140 
43-80 
2-3 
43-90 
18-2 
43-90 
2-9 
44-00 
25-0 
44-00 
4-1 
44'48 
35-5 
44"48 
5-8 
44-58 
61-0 
44-58 
10-0 
44-78 
81-0 
44-78 
13-2 
44-88 
92-0 
44-88 
15-0 
44-88 
111-0 
44-88 
18-1 
45-08 
137-0 
45-08 
22-3 
45-18 
160-0 
45-18 
26-2 
45-33 
190-0 
45-33 
31-0 
45-37 
226-0 
45-37 
36-7 
45-57 
277-0 
45-57 
45-2 
45-05 
309-0 
45-67 
50-4 
45-80 
346-0 
45-80 
57-1 
45-98 
390-0 
45-98 
64-0 
46-20 
444-0 
46-20 
72-7 
46-55 
510-0 
46-55 
83-2 
47-73 
568-0 
47-73 
93 
48-61 
510-0 
48-61 
83-2 
49-20 
444*0 
49-20 
72-7 
49-50 
390-0 
49-50 
64-0 
49-70 
346-0 
49-70 
57-1 
49-89 
309-0 
49-89 
50-4 
50-00 
277-0 
50-00 
45-2 
50-18 
226-0 
50-18 
36-7 
50-47 
190-0 
50-47 
3P0 
50-61 
160-0 
50-61 
26-2 
50-77 
137-0 
50-77 
22-3 
51-07 
111-0 
51-07 
18-1 
51-39 
92-0 
51-39 
15-0 
51-55 
81-0 
51-55 
13-2 
51-85 
61-0 
51-85 
10-0 
52-20 
35-5 
53-20 
5-8 
54-54 
25-0 
54-49 
4-1 
54-54 
18-2 
54-40 
2-9 
55-74 
14-0 
55-57 
2-3 
56-95 
9-0 
56 - 75 
1-5 
Dr. Pole. —In some cases of colour-blindness it does not seem as if there were any 
diminution in the range of vision along the spectrum as compared to that of normal 
sight. Such a case we had in Dr. Pole, F.Pt.S., who has given us permission to 
mention his name, as he has described in a very interesting paper in the Phil. Trans, 
(vol. 149 (1859) p. 323), an examination of his own eyes he himself made by another 
method. 
From this paper it appears that with him the sensation of red is altogether absent, 
but that red appears to him as yellow. He described to us certain shades of orange 
