Diagrams for n terms. 



A 



267 



This represents a universe with its A and not- A " compart- 

 ments." The quantitative relation of the compartments being 

 insignificant, they may for convenience be represented as 

 equal. 



The introduction of a second term divides each of the exist- 

 ing compartments. This may be done by a line drawn at 

 right angles to our perpendicular and through its centre, 



thus : — 



A a 



B 



The four compartments represent the sub-classes A B, A b, 

 «B, ab. 



A diagram for four terms would require two more perpen- 

 dicular and two more horizontal dividing lines, thus : — 





A 







A 



c 



a 

 C 



a 



e 



BD 











Bd 











bB 











bd 











X2 



