Source : Webster's Revised Unabridged Dictionary (1913)

Perspectograph \Per*spec"to*graph\, n. [L. perspectus (p. p. of
   perspicere to look through) + -graph.]
   An instrument for obtaining, and transferring to a picture,
   the points and outlines of objects, so as to represent them
   in their proper geometrical relations as viewed from some one
   point.