Single-Handed Dividers

From Inventions

Name in use since the 16th century in the form "Seste da carteggiare".

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

- Museo Galileo, Institute and Museum of the History of Science, Florence
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.

- Museum of the History of Science, Oxford
Museum of the History of Science, Oxford, inv. 42018
Museum of the History of Science, Oxford, inv. 57840

Links (External)

http://wiki.monticello.org/mediawiki/index.php/Single-Handed_Divider (English)

Images

Leonardo da Vinci. Il manoscritto H / trascrizione diplomatica e critica di Augusto Marinoni. 1986, c. 108v (H3, c. 35v).	Giovanni Pomodoro, La geometria pratica, Roma, 1599, tav.I, particolare.	Benvenuto Della Volpaia, Macchine e strumenti, ms., ca. 1520, Venezia, Biblioteca Marciana, It. IV, 41 (= 5363), c. 43 r.
Nicolas Bion. Traité de la construction et des principaux usages des instruments de mathematique, Paris, 1725, tav. 8.