-45- 



291 



remedy it. Introduce the image of the point sovirce at Q. 



relative to the sphere. This image is a point source of 



2 A ' 



strength A •=— at the inverse point Q, and a uniform 



^^ 2 1 

 lire sink of strength A x per unit length extending from 



to Q, ; this process continues and requires the use of 



theorem 2 for the images relative to the sphere. The successive 



images fit very neatly together, as indicated in the diagram. 



