Sextant

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The design for this type of sextant was patented in 1788 by Edward Troughton, a scientific instrument maker based in London. This brass example was made around 1820, probably by Troughton.

The 10-inch 'pillar frame' sextant has two thin frames of plate brass held together by a series of brass pillars. It has a platinum scale (which would not tarnish), an early example of the recently discovered metal being used in instrument design.

The English chemist, William Hyde Wollaston (1766-1828) managed to isolate platinum chemically in 1804. Troughton, who had introduced a new method of engraving sextant scales in 1785, realised that the hardness of this metal made it ideal for scale engraving.

Record details

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• Online ID: 000-100-104-300-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland
  Project description   View all records in project
• Ref: National Museums Scotland  T.1987.137
• Date: Around 1820
  c. 1820
  
• Material: Brass, platinum. Inscription: Troughton London platina 1251
  Sextant / case
  
• Dimensions:
• What: Sextant / case
  
• Subject:
• Who: E. Troughton, London (Maker)
  The Leith Nautical College Collection
  
• Where: England, London
  
• Event:
• Description: Ten inch double frame sextant in a fitted case, made by E. Troughton of London about 1820
  
• References:
  • Chaldecott, John A., 'Platinum and Palladium in Astronomy and Navigation: The Pioneer Work of Edward Troughton and William Hyde Wollaston' in Platinum Metals Review 31 (1987) pp 91-100 
  • For Troughton, see McConnell, Anita, Instrument Makers to the World: A History of Cooke, Troughton & Simms. York: 1992, esp. pp 14-24 
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