Heliotrope (instrument)

For other uses, see Heliotrope (disambiguation).
Heliotrope (c. 1878): B.A. Colonna collection (NOAA). This may be the very one Colonna surveyed from 192 miles away.
Gauss's Heliotrope (c. 1822)
Wurdemann's Heliotrope (1866)
Coast Survey, Steinheil, and simple heliotropes c. 1898

The heliotrope is an instrument that uses a mirror to reflect sunlight over great distances to mark the positions of participants in a land survey. The heliotrope was invented in 1821 by the German mathematician Carl Friedrich Gauss.[1][2] The word "heliotrope" is taken from the Greek: helios (Greek: Ἥλιος), meaning "sun", and tropos (Greek: τρόπος), meaning "turn".

  1. ^ Dodd, A.; Smith, A. (1822). "The Heliotrope, a New Instrument". Arts and Sciences. The Gentleman's Magazine. 92, Part 2: 358.
  2. ^ Dunnington, G. Waldo (1955). Carl Friedrich Gauss: Titan of Science. New York: Exposition Press. pp. 122–127, 119, 221. ISBN 0-88385-547-X.