Method of deter 



manna 



Surface- Tension of Liquids. 591 



where K and e are arbitrary constants to be chosen to satisfy 

 the initial conditions. Thus the segments of the bar are like 

 those of a string fixed at the ends. The frequencies of the 

 possible tones are, however, quite different. For, in this case 

 of the bar the frequencies are proportional to n 2 instead of to 

 n simply as for a string. Thus the frequency of the nth tone 

 is given by 



/cbn 2 7r 



N = 



W 



= n 2 N, 



(25) 



University College, Nottingham. 

 May 30, 1907. 



LVIII. The Curvature Method of determining the Surf ace- 

 Tension of Liquids. By C. V. Raman, M.A* 



[Plate XV.] 



LORD KELVIN, in his lecture on Capillarity (published 

 in his ' Popular Lectures and Addresses '), describes 

 this method as a practicable one for measuring the surface- 

 tension of liquids. In the following account is described an 

 arrangement by which this method is rendered a convenient 

 and fairly accurate one, and the results of a series of deter- 

 minations made by the method are tabulated. 



Ff?E£ Surface 



OF LiQU/O 



/?r/s oFy 



The Theory of the Method. 



Let ADB be the principal section of a drop hanging down 

 from a tube, and p the radius of curvature of ADB at the 

 * Communicated by the Author. 

 2R2 



