330 Mr. E. J. Chapman 07i the Notation of Crystals. 



Fiff. 10. 



Tri clinic System. 



Monaxial Planes : — 



P — M — L, as in the preceding 

 system. 



Di axial Prismatic Planes : — 

 B-B^; iy-T>x. 



Diaxial Pyramidal Planes : — 

 A; AA; E; EE: with their va- 

 lues K m, as above. 



TO' ' 



Triaxial Pyramidal Planes : — 

 O; OO; U; W; with their va- 

 lues -, m. 



In conclusion, we will tabulate the proposed notation, for 

 the sake of reference, with those of Weiss and Rose, Nau- 

 mann. Levy and Dufrenoy, and Mr. Griffin. It should be 

 observed, however, that the latter author adopts throughout 

 each crystallographic group one uniform system of three rec- 

 tangular axes, differing only in regard to their relativelengths*. 

 In the following tables the forms are arranged in accordance 

 with the number of axes which they cut, monaxial forms 

 being placed first. 



Monometric System. 



* System of Crystallography, with its Applications to Mineralogy. 1841. 



