Tension of Soap Solutions for Different Concentrations. 671 



0-025 0-05 0-10 0-125 0-15 O-S 75 0-20 



Co nee rit ration: ^rrns. per 100 c.c. of Solution. 



Conclusions. 



(1) These experiments place beyond all doubt the fact 

 that the surface tension of soap solutions is the same for all 

 concentrations between very wide limits. 



(2) They further lend weight to the reliability of the 

 bubble method for studying the surface tension of soap 

 solutions although the apparatus is seemingly more complex 

 than that for the capillarity method. 



(3) The close agreement between the results obtained by 

 the soap-bubble method and those obtained by the capillarity 

 method further shows that the angle of contact in this case 

 is 0, as has also been conclusively established by the experi- 

 ments of Bosanquet and Hartley (Phil. Mag. vol. xlii. Sept. 

 1921) and Richards and Caver (Journal American Chemical 

 Society, 1921, p. 827). 



Department of Physics, 



Maharajah's College, Vizianagram, 

 15th November, 1921. 



