for determining the viscosity of very viscous liquids 27 



represents, not a single straight line*, but a family of approxi- 

 mately straight lines. Each line can be represented by the equation 

 MT =al + p. For this group of curves d {MT)ldl tends to a definite 

 value as M increases, i.e. the curves approach a certain border line 



o lO 10 30 it-o so €0 70 60 90 100 110 1Z0 r3o i4o ;5o 160 170 180 190 200 aw 



which is comparable with Searle's straight line. The coefficients 

 a and ^ have been calculated for each line by the method of least 

 squaresf , using the formulae 



1.1 . HMT - 6111 . IslMT ^ 1.1 . i:iMT - IIMT . ZV- 



(SZf - 6S/2 



(S^)2 - 6SZ2 



* G. F. C. Searle, loc. cit., p. 604. 



t F. Kohlrausch, Lehrbuch d. jn-aktischen Physik, p. 13, 1914. 



