Marching line

A liquid filled compass.

Marching lines are a pair of lines drawn on the glass of a compass, and arranged at 45 degrees to each other. These are an essential component in hiking through the wilderness. Most modern compasses have adjustable luminous marching lines.

See also

• Azimuth
• Beam compass
• coordinates
• fluxgate compass
• gyrocompass
• Gyrosin compass
• gyrostatic compass
• inertial navigation system
• pelorus
• radio compass
• radio direction finder
• surveyor's compass, or circumferentor

External links, resources, and references

• USGS Geomagnetism Program
• Amir Aczel, The Riddle of the Compass: The Invention that Changed the World, ISBN 0-15-600753-3
• Joseph Needham, Colin A. Ronan: The Shorter Science & Civilisation in China Vol 3 Chapter 1 Magnetism and Electricity.
• Science Friday, "The Riddle of the Compass" (interview with Amir Aczel, first broadcast on NPR on May 31, 2002).
• Paul J. Gans, The Medieval Technology Pages: Compass
• Frederic Lane, "The Economic Meaning of the Invention of the Compass", American Historical Review, vol. 68, pp. 605-617 (1963)
• The Tides By Sir William Thomson (Lord Kelvin)
• Evening Lecture To The British Association At The Southampton Meeting on Friday, August 25, 1882 [1]. Refers to compass correction by Fourier series.
• http://en.wikipedia.org/wiki/Image:Liquid_filled_compass.jpg
• Admiralty manual of navigation, Chapter XXV The Magnetic Compass (continued) the analysis and correction of the deviation, His Majesty's Stationary Office, London, 1914.
• Arrick Robots. Robotics.com Example implementation for digital solid-state compass. ARobot Digital Compass App Note
• Williams, J.E.D. From Sails to Satellites. New York: Oxford University Press, 1992.
• Frances and Joseph Gies, Cathedral, Forge, and Waterwheel subtitled "Technology and Invention in the Middle Ages".
• Petra G. Schmidl Two Early Arabic Sources on the Magnetic Compass

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