258 RELATION OF DECREMENTS TO 



The rhombic Dodecahedron. 

 Fig\ 309. 



Simple and mixed decrements on the obtuse solid angles. 



v 

 General symbol P A P , represents the classes e,f,&g. 



Ifp^> 1, the symbol represents class f. 



p = 1, . mod. e. 



p < 1, . . . . . . . . class g. 



Intermediary decrements on the obtuse solid angles 

 produce the planes of class h, which class may be 

 generally represented thus : 



(B' P B q B" r : B'q Bp B"r). 



Simple and mixed decrements on the acute solid 

 angles, produce the planes belonging to classes a 

 and b. 



General symbol P E P . 



p 



If p zz: 1, the symbol represents mod. a. 

 p > 1, class b. 



Intermediary decrements on the acute solid angle 

 consist of two kinds, producing the planes of classes 

 c and d. 



The general symbol representing class c, is 



(B P B'q b' q br). 



The general symbol representing class d, is 

 (Bp B'q b'r bs : B P B'r b'q bs). 



