Compasses without Center
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| - | |descrizione= [[ | + | |descrizione= [[Compasses]] for drawing large circles described by Giacomo Contarini as an invention of Fabrizio Mordente. The instrument is composed of four orthogonal rules, three of them fixed and one mobile. The user first drew a circle with an [[Compasses |ordinary compasses]], then adjusted the instrument so that the points of the fixed lateral rules and the central mobile one all rested on the same circumference. He then slid the compass along the circumference so that the point opposite the central ruler could trace a circle of larger radius, repeating this operation as many times as necessary. |
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Current revision as of 12:14, 27 July 2010
Has no specific name.
Contents |
Inventor
Fabrizio Mordente
Historic Period
ca. 1570
Description
Compasses for drawing large circles described by Giacomo Contarini as an invention of Fabrizio Mordente. The instrument is composed of four orthogonal rules, three of them fixed and one mobile. The user first drew a circle with an ordinary compasses, then adjusted the instrument so that the points of the fixed lateral rules and the central mobile one all rested on the same circumference. He then slid the compass along the circumference so that the point opposite the central ruler could trace a circle of larger radius, repeating this operation as many times as necessary.
Bibliographical Resources
Contarini,Giacomo, Figure d'Istromenti Matematici e loro uso, ms, ca. 1590, Oxford, Bodleian Library, Ms. Canon. Ital. 145.
Author of the entry: Filippo Camerota
