Single-Handed Dividers
From Inventions
Name in use since the 16th century in the form "Seste da carteggiare".
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Description
Instrument for transferring measurements and distance readings onto nautical charts. The legs of the instrument comprise a semi-circular section and a straight section tapered to a point. The dividers could be opened with a single hand by applying finger pressure to the curved section. Used in navigation to plot routes on sea charts. The name is found in a manuscript by Benvenuto della Volpaia, who describes the instrument as "Seste da carteggiare" (dividers for plotting routes).
Bibliographical Resources
Della Volpaia, Benvenuto. Macchine e strumenti, ms., ca. 1520, Venezia, Biblioteca Marciana, It. IV, 41 (= 5363), c. 43 r:
Pomodoro, Giovanni. Geometria prattica tratta dagl'Elementi d'Euclide ed altri Auttori da Giovanni Pomodoro Venetiano Mathematico eccellentissimo descritta et dichiarata da Giovanni Scala Mathematico, Stefano de' Paulini, Roma, 1599.
Existing Instruments
Florence, Museo Galileo. Institute and Museum of the History of Science, inv. 1478.
Florence, Museo Galileo. Institute and Museum of the History of Science, inv. 1479.
Images
Author of the entry: Filippo Camerota