ON COLOUR PHOTOMETRY. 
547 
Table III. (continued). 
I. 
II. 
III. 
IY. 
Y. 
VI. 
E. 
Reduction of 
L. 
Persistency curve 
Scale 
Wave- 
original 
luminosity 
in millionths 
to cause 
extinction. 
Luminosity 
E x L 
650 
IT 
number. 
length. 
of 
original beam. 
100 ' 
( Maximum = 100). 
22 
4578 
80 
1-4 
1T20 
8-41 
21 
4548 
95 
1-2 
1-140 
7-22 
20 
4517 
107 
1-08 
1T56 
61 
19 
4488 
124 
•94 
1-165 
5-23 
18 
4459 
140 
•86 
1-204 
4-64 
17 
4437 
160 
•78 
1-228 
4-1 
16 
4404 
180 
•70 
1-260 
3-60 
15 
4377 
200 
•62 
1-240 
3-25 
14 
4349 
220 
•56 
1-232 
2-95 
13 
4323 
240 
•50 
1-200 
2-7 
12 
4296 
270 
•45 
1-215 
24 
11 
4271 
300 
•40 
1-200 
2-18 
10 
4245 
335 
•34 
1T39 
1-94 
9 
4221 
375 
•30 
1125 
173 
8 
4197 
430 
•26 
1-118 
1-51 
7 
4174 
490 
■22 
1-078 
1-32 
6 
4151 
510 
•18 
•918 
1-27 
5 
4131 
640 
•16 
1-024 
1-01 
4 
4106 
750 
•14 
1-050 
0-86 
4 A 2 
