538 



Sir W. Thomson on Maximum and 



parallel to itself within the enclosure. It is shown, marked S, 

 in figs. 6, 7, 8, 9 : representing the solution of our problem 



Fig. 6. 



Fig. 7. 



Fig. 6.JDotted circle with arrowheads refers to the velocity of the stirrer 

 and of the dimple, not to the velocity of the fluid. 

 Arrowheads in the vortex refer to velocity of fluid. Arrowheads 

 in the irrotational fluid refer to the stirrer and dimple. Arrow- 

 heads in a b prefer to motion of irrotational fluid relatively to the 

 dimple. 



Fig. 7. 



Fig. 8. 



Fig. 9. 



Fig. 8. Arrowheads refer to motion of the stirrer, and of the vortex as a 



whoie. 

 Fig. 9. Arrowheads on dotted circle refer to orbital motion of c, the 



centre of the vortex. Arrowheads on full fine curves refer to 



absolute velocity of fluid. 





