560 VISCOSITY. 



In the First Class we have 



p = const., 



d d 



and therefore asu + yv 4- zw 



In the Second Class we have 



P=Pn, 



and 



[CHAP, xi 



(8); 



.(9). 



.(10), 

 (11), 



where f, ?;, f denote the component rotations of the fluid at the 

 point (as, y, z). The symbols % n , &amp;lt;f&amp;gt; n , p n stand for solid harmonics 

 of the degrees indicated. 



The component tractions on the surface of a sphere of radius r 

 are given by 



- (xu + yv + zw), 



= xp + p 



j. 



^ ( r T^ - 1 J 



A 6 T 



T- + 



I 



In the solutions of the First Class we find without difficulty 



