44 



TERMINOLOGY. 



Fig. 97, the same, with the acute solid angles replaced by sin- 

 gle planes. 



Fig. 98, the same, with lateral solid angles replaced by single 

 planes. 



Fig. 97. 



Fig. 98. 



The doubly oblique Prism presents a still more remarkable in- 

 stance of irregularity. According to the explanation given of this 

 solid, (. 45.) each one of the four edges, and each one of the four 

 solid angles of its base, is in a different position. Here also the 

 modifications, which take place, follow the general law announced 

 above ; similar replacements occurring only upon similar edges or 

 angles. 



Fig. 99 represents the doubly oblique Prism, with its acute ter- 

 minal edges B,* replaced by single planes. 



Fig. 100, the same, with its acute terminal edges C replaced by- 

 single planes. 



Fig. 99. 



Fig. 100. 



* See Fig, 35. 



