heliography

Heliography \He`li*og"ra*phy\, n.
   1. [Helio- + -graphy.] The description of the sun.
      [Webster 1913 Suppl.]

   2. The system, art, or practice of telegraphing, or
      signaling, with the heliograph.
      [Webster 1913 Suppl.]

   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.
      [Webster 1913 Suppl.]

   4. Photography. [Archaic.] --R. Hunt.
      [1913 Webster]