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

\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.