252 ON THE USE OF SYMBOLS. 



denote the secondary ones, as in the sollowing ex- 

 ample. 



Thus, if a right rhombic prism should be found 

 containing the modifying planes belonging to the 

 classes , c, e, h, and g, and also containing the pri- 

 mary planes, the representative symbol might be this. 



, . 4 



G 1 M H 2 B E A P 

 h M g e c a P 



Here the laws of decrement producing the second- 

 ary planes are represented by the upper series of 

 characters ; and the lower series consists of the let- 

 ters which are placed on the figure of the crystal, to 

 distinguish the secondary pjanes. 



