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Name coined by the inventor (in French, trigometre) combining the Greek words trigonos (triangular) and metron (measure).



Philippe Danfrie

Historic Period



Instrument described by Philippe Danfrie, which replicates the system of graduated arms with sights hinged onto a fixed base, already used in the surveying instrument by Bladassarre Lanci, in the holometer, and in Bernardo Puccini's gnomon. At the hinge points the two vanes (one of them sliding) carry a graduated arc for measuring angles, while the fixed base, mounted on a stand, houses a compass. Its field of operation covers all of the standard operations, including land surveying.

Bibliographical Resources

Danfrie, Philippe. L'usage du trigometre, in Various mathematical exercises and notes, New York, Columbia University, Butler Library, Smith Collection 44.
Danfrie, Philippe. Déclaration de l'usage du graphomètre par la pratique duquel l'on peut mesurer toutes distances des choses de remarque qui se pourront voir et discerner du lieu ou il sera posé et pour arpenter terres, bois, prés et faire plans de villes et forteresses, cartes géographiques et généralement toutes mesures visibles, et ce sans règle d'arithmétique... . A Paris, chez ledict Danfrie, 1597.

Author of the entry: Filippo Camerota

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