﻿188 Mr. F. Lloyd Hopwood on the 



The calculated values o£ x given in the above table were 

 obtained from the equation 



Both the quantities a and n of equation (A) are functions 

 of the time which has elapsed since sagging began, a showing 

 a big percentage variation and n a comparatively small 

 variation, during a complete run. 



The relation between a and time of sag is accurately 

 expressed by the equation * 



a = u-/3logt (B) 



This is clearly shown in fig. 4. 



Fig. 4. 













a & log. t fmiros 



) 



\^ 











\ 





r 







\o 





±cc 











1 



j 



5-4 7-4 



The approximate values of a and /3 are 

 a = 9'38, £=1-31I. 

 The result (B) is of some importance, for it is of the same 



* Equation (B) obviously cannot hold from the instant sag commences. 



