Gunter's Scale

Grasselli y Zambra1860

Naval Museum

Naval Museum

This instrument has 2 graduated rulers joined at one end by a hinge. When they are fully opened out they form a straight, double-length ruler. Various scales are engraved on the compass faces: planes, polygons, equal parts, strings, solids, and metals.

This type of mathematical instrument was mainly used to solve navigational problems involving flat and spherical triangles. A compass was also required to use it correctly. The book that explained how to solve these problems was "Description and Use of the Sector, the Crosse-staffe, and other Instruments" published in 1623 by English mathematician and astronomer Edmund Gunter (1581–1626).

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  • Title: Gunter's Scale
  • Creator: Grasselli y Zambra
  • Date Created: 1860
  • Location Created: Madrid, Spain
  • Provenance: The piece was made by the firm Grasselli y Zambra around 1860. The company had a shop selling instruments for physical optics, geodesy, astronomy, and cartography, among other fields. The item was donated to the museum by Emilio Aleman de la Escosura on September 29, 1997.
  • Type: Scientific Instrument
  • Original Source: Museo Naval Madrid.
  • Rights: Museo Naval, Madrid - All Rights Reserved
  • Medium: Nickel