EQUIVALENTS. 739 



alone as was intended to be done a single ball upon the board, indicated 

 by the circle around it in the cut. 



By playing the " equivalent " method you will always arrive at this 

 result a single ball in No. 25. It may now be perceived how we cannot 

 only arrive at a satisfactory solution, but by means of the rings ascertain 

 whether we shall succeed in our game without disturbing a single ball. 

 After some experience we may even learn to dispense with the rings 

 altogether. 



Fig. 870. Solitaire board. 



