72 



TABLE I. 



A fresh solution was used in the last three measurements. 



4. The correction varies directly as the thickness of the frame, Fig. 5. Ob- 

 servations with two frames of varying thickness are sufficient to determine the 

 actual film weight and hence the tension. 



1.020 



1.020 



1.010 



V 



.ms 



y02 OlM 006 XI08 Oin (S\i .0I4 016 Uls .1/211 .<til .C2J .1)26 



Ms 



