riJYSTALLOGRAl'IIY 



11 



saint- /<>ne ; draw c'c'" parallel to pp', c'"c" parallel to p'p", and so 

 on around the four sides of the base above and below. The unit 

 pri-ni. m (110), is a member of the 

 >:nne /out \ and its intersection with 

 the pyramid will be parallel to the 

 intersections of the base and pyra- 

 mid. If the prism cuts the b axis 

 at m, then m'm" drawn through m 

 parallel to oc will represent its edge 

 in projection, and m', m" will be 

 points on the intersection of the 

 prism and pyramid; draw m'm'" 

 parallel to p'"p, and so on around the pyramid above and below, 

 dotting edges which will appear behind. To project the remaining 

 form d (102) = 2 ft: oob : c, lay off on the ft axis, 2 a, connect 2 a 

 with c and c ; these lines will be the intersection of the dome 

 >with the axial plane coft. Move 2 ac in parallel to itself, until it 

 cuts the edge of the pyramid at d'" and the base at e, the inter- 



FIG. 63. 



FIG. 64. One Octant of 3 a : 3 a : a. 



section of d and c will be parallel to the b axis, as both faces are 

 parallel to b ; draw ee" parallel to p'p"' and connect e"d'", e"'d'", 



