Drawing Instrument for Sundials
From Inventions
Revision as of 10:09, 27 July 2010
Has no specific name.
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Inventor
Fabrizio Mordente?
Historic Period
XVI century
Description
Instrument illustrated by Giacomo Contarini as one of Fabrizio Mordente’s inventions. Although there is no text to explain its operation, it was probably designed for drawing sundials. On a horizontal half-disk is a dial carrying a compass and a long rod on which slides a graduated disk with a diagram of the zodiacal arc. The user fixed the horizontal half-disk to a table, and, establishing a fixed reference point (the façade of a building, for example), rotated the dial in the direction of the local meridian, inclining the rod according to the latitude of the place and fixing the zodiacal disc in relation to the desired size of the drawing. By means of a string, the zodiacal signs were then projected onto the horizontal sheet of flat paper.
Bibliographical Resources
Contarini,Giacomo, Figure d'Istromenti Matematici e loro uso, ms, ca. 1590, Oxford, Bodleian Library, Ms. Canon. Ital. 145, cc. 28-29.
Author of the entry: Filippo Camerota
