Source : Webster's Revised Unabridged Dictionary (1913)

Heliography \He`li*og"ra*phy\, n.
   1. The description of the sun.

   2. The system, art, or practice of telegraphing, or
      signaling, with the heliograph.

   3. An early photographic process invented by Nic['e]phore
      Niepce, and still used in photo-engraving. It consists
      essentially in exposing under a design or in a camera a
      polished metal plate coated with a preparation of asphalt,
      and subsequently treating the plate with a suitable
      solvent. The light renders insoluble those parts of the
      film which is strikes, and so a permanent image is formed,
      which can be etched upon the plate by the use of acid.

Heliography \He`li*og"ra*phy\, n. [Helio- + -graphy.]
   Photography. --R. Hunt.