Jan. 18, 1918] 



Studies on Liquid Films 



385 



In order to determine the time at which each drop had to fall the 

 volumes of the successive bul)bles were calculated and their differ- 

 ences tabulated. Havino^ fixed upon a suitable rate of blowing, the 

 intervals between the drops that corresponded to the successive 

 differences in volume were at once obtained. The rate of blowing was 

 216 c.c. per minute, so that the whole group took about 21 minutes 

 to make, the intervals between the drops decreasing from about 

 4J minutes at first to about half a minute at the end. The surfaces 

 of the glass plate and nozzle were first moistened with soap solution. 



Fig. 25. 



By the eighth day the black zones occupied 90 to 95 per cent, of 

 the surfaces. Some experiments were made subsequently on the 

 manner of diffusion of hydrogen through the group. 



Film Coxtours Showx by Shadow. 



When the shadows of these film complexes were thrown on a 

 transparent screen every detail of their structure was clearly shown. 

 For lecture i:)urposes an arc lamp was used to produce these shadow- 



