ITS MODIFICATIONS. 169 



Modifications. 



Class a. Solid angles replaced by single scalene 

 triangular planes, which incline on the three adjacent 

 primary planes at unequal angles. 



The new figures which would be ultimately pro- 

 duced by this class of modifications, would be a series 

 of octahedrons with rhombic bases. 



Class b. Greater terminal edges replaced by single 

 planes. 



Class c. Lesser terminal edges replaced by single 

 planes. 



The new figures which would be produced by a 

 combination of modifications b and c, would be a 

 series of octahedrons with rectangular bases. 



Class d. Lateral edges of the prism replaced by 

 single planes. 



A series of right rhombic prisms would result from 

 this class of modifications. 



If more planes than one be found modifying any 

 one of the edges or angles of this form, they are sup- 

 posed to result from as many individual modifications, 

 as there are planes upon the particular edge or angle 

 on which they occur. 



The planes produced by modifications class by c, 



