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probably made in Paris

Postcard of Graphometer.
© National Museums Scotland


A graphometer is a surveying instrument used for measuring angles. This brass example (pictured here with its leather case) was made in 1774, probably by Louis-Pierre-Florimond Lennel, a scientific instrument maker based in Paris.

The large graphometer, typical of French survey instruments of the period, has a telescopic sight, attached to a rotatable alidade. It consists of a pierced semicircular plate, carrying at its centre a silvered compass, contained in a glazed box suspended below the plate. A second, fixed, telescope is mounted below the plate.

The instrument may well have been used in the French National Survey as its leather case carries the official fleur-de-lys stamp. This survey took place throughout the 18th century, but never received sufficient state backing: triangulation work began in 1747, with funding withdrawn in 1756. By 1784 only Brittany was unsurveyed, and this was not completed until well after the French Revolution, in 1818.

Record details

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Online ID: 000-100-104-247-C
Image Rights Holder: National Museums Scotland
Project: 0098: National Museums Scotland
Project description | View all records in project
Ref: National Museums Scotland  T.1973.71
Date: 1774
Material: Leather case
What: Graphometer / case
Subject: 5. CARTOGRAPHY, Surveying (Departmental Classification)
Who: E. Lennel, Paris (Maker)
Where: France, Paris
Description: Graphometer, in a leather case, signed by E. Lennel of Paris, 1774
  • Bennett, J.A. The Divided Circle: A history of instruments for astronomy, navigation and surveying. Oxford: 1987. p 87 
  • For Lennel, see Daumas, M. Scientific Instruments of the 17th and 18th Centuries and their Makers. London: 1972, pp 262 & 332, and Augarde, Jean-Dominique, 'La fabrication des instruments scientifiques du XVIIIe siecle et la corporation des fondeurs' in B 
  • Wynter, H. & Turner, A., Scientific Instruments. London: 1973, p 158 
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