34 Mr Molin, An examination of Searle's method, etc. 



Table 6. 

 Values of y. 



Wlien the various values are given the same weight, the 

 mean value of y is 89-7, and then 17 = 2754-. 



§ 9. Diagram 3 and formula (5) show that 77 cannot be re- 

 garded as independent of Q. unless Q. exceed a certain value, in 

 this case 0-9. Since Q. is related to the rate of shearing rdw/dr, 

 according to the formula 



it follows that 7y is a function of the rate of shearing. Hence, the 

 assumption on which formula (1) is based, viz. that rj is independent 

 of the rate of shearing, seems to be unjustifiable for small values 

 of the rate of shearing, at least in the case of the highly viscous 

 liquid used in these experiments. 





