PROFESSORS A. W. REIXOLD AND A. W. RtTCKER OX 
486 
The following table (Table X.) refers to films I. and II., September 24, and 
films I. and II., September 29. In the case of the first two the air in the case was 
moistened by the tray of liquid alone without the aid of the blotting paper. When 
the second pair were observed no precautions were taken to moisten the ah’. 
Column I. gives the date and number of the film. 
Column IT. the apparent mean thickness in terms of 10~ 5 centims. 
Column III. the number of minutes (in) since the formation of the film. 
Column IV. jp or the number of parts by volume of water lost out of 100 parts of 
the original standard solution. 
Column Y. the values of 
Am 
Table X. 
I. 
II. 
III. 
IV. 
V. 
m. 
P■ 
Ap 
Am 
September 24, I. . 
14-0 
10-8 
19-0 
073 
8-0 
20-8 
20-3 
0-17 
4-5 
88-3 
23-3 
September 24, II. . . 
14-0 
61 
16-2 
0-16 
8-0 
15-6 
177 
0-22 
4-5 
336 
217 
September 29, I. 
140 
9-9 
12-5 
0-28 
8-0 
18-2 
14-8 
| 
September 29, II. . 
14-0 
6-4 
17-3 
012 
8-0 
13-8 
18-2 
0-25 
4-5 
247 
20-9 
Bearing in mind that the inner surfaces of these films were in the immediate 
neighbourhood of the liquid contained in the lower cup to the edge of which the 
cylinder was attached, we may from this table draw the following conclusions :— 
(1.) A soap film, the area of the external surface of which is about 45 square centims., 
enclosed in a space about 3900 cubic centims. in volume, and the inner surface of which 
is in contact with air permanently nearly saturated at the tension proper to the 
