Hele-Shaw & Hay. 
Phil. Trans., A., Vol. 195, Plate 15 . 
Infinite Circular Cylinder in uniform field. 
Permeability = 2. 
Infinite Circular Cylinder in uniform field. 
Permeability = 100. 
Solid Circular Cylinder shielded by hollow 
one. Permeability = 100. 
Infinite Hollow Elliptic Cylinder in uniform 
field. Permeability = 100. 
