10 Mr. W. N. Bond on the Properties of 



pseudo-viscosity, which will give some means of comparing- 

 the rate of bending with that of viscous solids under similar 

 conditions. 



Table I. 



t\/t n j r in • Maximum Stress in 



Method oi .Experiment. ^ , 2 



^ Dynes/ on 2 . 



Cantilever 4175 X 10 7 



4-64 „ 

 5-85 



6-03 „ 

 8-35 



Beam 313 



413 

 6-20 



9-39 „ 

 14-55 



Stretching 2'38 



Viscosity of Ice j ^'2 * J^ to (Deeley & Parr, 1913.) 





A. 







89 X 



10 14 





2-09 



,, 





•34 



j 





•093 







•30 



» 



over 



32 



•033 

 7-04 

 •44 

 •106 



| 



over 



409 



„ 



In the above table, X is what Trouton* terms the co- 

 efficient of viscous traction, and is, according to him, three 

 times the viscosity. It will be seen that the values of the 

 pseudo-viscosity vary considerably with the stress. 



If we assume the viscosity of ice to be as given by Deeley 

 and Parr f, the above table shows that the rate of bending of 

 the crystals of ammonium nitrate under stresses of the 

 order of those employed in these experiments is about equal 

 to that observed in glacier ice under similar conditions. 



Fig. 10. 



Fig. 10 shows the forces that are acting on one half of the 

 crystal when bent by the second method. At any section of 



* Prof. Trouton, Coeff. of Viscous Traction, etc., Proc. R. Soc. A r 

 vol. lxxvii. 1906. 



t R. M. Deelev & P. H. Parr, Phil. Mag. xxvi. pp. 85-111, July 

 1913, and xxvii. pp. 133-176, Jan. 1914. 



