igoj] Henderson — Graphical Representation. 133 



Steiener points yielded by the projection, the other not being 

 shown for the reason mentioned above. 



A final consideration was the construction of the conic sec- 

 tion, given by the intersection of the quadric cone (containing 

 the lines 1, 2, 3, 4, 5, 6) with the plane of projection. The 

 six points 1, 2, 3, 4, 5, 6 lie on this conic section and hence it 

 was constructed by points by means of the very theorem 

 under consideration, viz. Pascal's Theorem.* 



* To prevent unnecessary complexity on the drawing, only one branch 

 of the hyperbola (the conic, in the present instance) is shown. 



