160 



The Ohio Journal of Science [Vol. XVIII, No. 5, 



ment between the two columns is seen to be very good and 

 fairly good for r/ = 7.15, the variation being in the opposite 

 direction. For 7/ = 9 the variation is greater and in the same 

 direction as for z/ = 8 cm. For 7/ = 10 and 11 cm. it is plain that 

 the theoretical and experimental curves can no longer be 

 extrapolated to the same value. Plainly the agreement gets 

 worse as y increases, due to the lack of constancy in column 20 

 for a given set. In column 24 is given the percent, of error 

 in column 20 as against the value given in column 23. 



4SS, 



The lower set of figures in columns 11 to 16 inclusive is 

 obtained by calculating Xs from the equation given above, 

 using the values for Ko/ k given in column 23. Since the equation 

 is transcendental the method of approximation has to be used. 

 Multiplying this As (theoretical) by *s' gives column 21. Com- 

 paring the two sets of figures in columns 11 to 16 inclusive we 

 get the per cents of error given in column 25. 



