14 
CAPTAIN ^y. DE W. ABNEY ON THE TRANS^^IISSION 
1st exposure. 
2nd exposure. 
Cell. 
Mean reading. 
Mean r 
eading. 
Value. 
Value. 
mite = 78. 
White = 100. 
White = 78. 
White = 100. 
3 in., clear . 
40 
51-5 
63 
41 
53 
61 
3 in., turbid 
54 
69 
40 
53 
70-5 
39 
„ action tlirougli clear water 6o , - _ 
1 st Exi30Sm'e j^^tion through turbid water ■" 40 ~ 
61 
2nd „ „ „ ~ 39 ” 1’564. 
Mean = l’o7. 
Photographic light passing through clear water = I’57 X 10’91 = 17‘1 times that 
passing through the turbid water. 
Taking the formula as before 
/r = 
log 17T 
3 ~^ 
9-8390 
— = -946. 
1st exposure. 
2nd exposui 
e. 
3rd exposure. 
Cells. 
ISIean reading. 
Mean reading. 
Mean reading. 
Value. 
Value. 
Value. 
White 
White 
White 
White 
White 
White 
= 78. 
= 100. 
= 78. 
= 100. 
= 78. 
= 100. 
1‘7 in., clear 
54 
69 40 
57 
73 
36 
68 
87 
22-5 
1’7 in., turbid . 
47 
60 50 
50 
64 
45 
64 
82 
28 
1 st Exposure 
action through clear water 
action through turbid water 
2 nd 
3rd 
3 3 
33 33 
Mean = ’800. 
40 
50 
45 
22-5 
28 
•800. 
•800. 
•800. 
b^hotographic light passing through clear water = '8 X = 5•OSS times that 
passing through the turbid water. 
