Graphometer
From Inventions
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| - | |descrizione= Instrument described by Philippe Danfrie, which may be seen as a half [[compass]]. The magnetic needle and the | + | |descrizione= Instrument described by Philippe Danfrie, which may be seen as a half [[compass]]. The magnetic needle and the diopter are found in fact at the centre of a semicircle with a degree scale, attached to a fixed base that carries sights. For measuring distances and surveying territories, the instrument requires two stations, whose alignment is verified through the sights on the fixed base. The diopter measures the position angles, which are later transcribed onto charts. |
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Revision as of 11:27, 27 July 2010
Name derived by the inventor from the Greek grapho (to describe, to paint, to draw) and metron (measure).
Contents |
Inventor
Philippe Danfrie
Historic Period
1597
Description
Instrument described by Philippe Danfrie, which may be seen as a half compass. The magnetic needle and the diopter are found in fact at the centre of a semicircle with a degree scale, attached to a fixed base that carries sights. For measuring distances and surveying territories, the instrument requires two stations, whose alignment is verified through the sights on the fixed base. The diopter measures the position angles, which are later transcribed onto charts.
Bibliographical Resources
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.
Existing Instruments
Firenze, Museo Galileo. Istituto e Museo di Storia della Scienza, Inv. 151.
Firenze, Museo Galileo. Istituto e Museo di Storia della Scienza, Inv. 3630.
Firenze, Museo Galileo. Istituto e Museo di Storia della Scienza, Inv. 3699.
Author of the entry: Filippo Camerota
