135 



accurate conception of his Pyramid of derivation, examples 

 of the mode in which it is constructed. 



When n = 1 there is one flat, When w = 2 there is one flat, 

 viz. viz. 



1,2 



2, 3 2, 4 

 2, 4 3, 4 



Let nx3, there will be two Let w = 4, there will still be 

 flats : two flats onlv : 



2, 3 



1,2 



1,3 



1,4 



1,3 



1,4 



2,4 



1,4 



2,4 



3,4 



2,3 



2,4 



2,4 



3,4 



1,2 



1,3 



1,4 



1,5 



1,3 



1,4 



1,5 



2,5 



1,4 



1,5 



2,5 



3,5 



1,5 



2,5 



3,5 



4,5 



