probably made in Paris

Semi-circumferentor

A semi-circumferentor (a semicircular graphometer) is a surveying instrument used for measuring angles. This brass example was made around 1775, probably by Jacques Baradelle, a scientific instrument maker based in Paris.

The instrument has an inset compass and is pierced and engraved with floral scrollwork. The outer edge is divided into 180 degrees in both directions. The alidade terminates in verniers with aperture sights and is signed 'Baradelle Paris'.

Instruments of this type were in general use on the Continent, especially in France, during the 18th and 19th centuries. Although it appears to be only half an instrument, the moving alidade allows measurements to be taken through a complete circle, while economising on brass.

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Online ID:	000-100-104-232-C
Image Rights Holder:	National Museums Scotland
Project:	0098: National Museums Scotland Project description \| View all records in project
Ref:	National Museums Scotland T.1967.77
Date:	Around 1775 c. 1775
Material:	Brass / silvered scale. Inscription: Baradelle Paris; NORD / N. N. Ouest / O. N. Ouest / OUEST
Dimensions:	7.19" H; 11.50" D; 9.94" D
What:	Circumferentor
Subject:	5. CARTOGRAPHY, Surveying (Departmental Classification)
Who:	Baradelle, Paris (Maker)
Where:	France, Paris
Event:
Description:	Brass half circle circumferentor by Baradelle of Paris, c. 1775
References:	Daumas, M., Scientific Instruments of the 17th and 18th Centuries and their Makers. London: 1972, p 288 Phillips, P., The Collectors' Encyclopedia of Antiques. London: 1973, p 604
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