10 
perspectives along the united nuclear beam, one towards the other, so as to bring into 
coincidence the two nuclear fulerums in the only united nuclear fulcrum, while the 
projectivity between the nuclear beams is preserved identically. This way we have 
eliminated from the representation of the take of the dihedral, developed in plane, the 
dimensions of topographic order d, and d, that caused us the greatest difficulty in the 
analogical translation of the projective outline. 
b) The whole of the take in reduced dimensions. 
Thanks to the consideration of the nuclear fulerums, it then always becomes possible 
and extremely simple to substitute the representation in scale but ''in toto" of the 
development of the take dihedral by a true representation of the general outline of the 
projectivity between the nuclear beams, in extremely reduced dimensions since the topo- 
graphic ones have totally disappeared. 
Such reduced representation, in virtue of the invariancy of the coordinates of the 
nuclear fulerums, in characterized by the symmetry of the centers of the two prospective 
  
  
Fig. 6. Open-face development of the take dihedral. 
frames, symmetry that is extended also to the swings g,, g, of the frames themselves in 
the equally elevated take arrangements (z, e,) to the positions of the nuclear points when 
the take arrangements are intrinsically symmetrical. (See Chapter II — d). 
The parameters of the general homographic plane in its reduced representation 
become: 
+ r, abscissa of the united nuclear fulcrum in respect to each of the two principal points 
of the photographic prospectives. 
g, | 
gà 
u, u,, abscissa of the nuclear points ) 
v, V5, ordinates of the nuclear points { 
swing of frames, in respect to the dihedral edge. 
in the photographic coordinate systems.