Gunner's Square

From Inventions

Current name for the quadrant widely used in the sixteenth century by gunners. The inventor, or divulger, Nicolò Tartaglia, called it simply squara = quadrant.

Described by Nicolò Tartaglia in two versions developed respectively for aiming cannon (with a longer leg to be inserted into the gun mouth and a quarter-circle divided into 12 points with plumb bob) and to measure the height and distance of a target. In the latter case, the quadrant has legs of the same length and a shadow square with plumb bob. Mounted on one side are the sights, which can also be used, thanks to the plumb bob, to level a terrain. In measuring unknown quantities, the operation of the gunner's quadrant is similar to that of the quadrant.

Bibliographical Resources

Tartaglia, Nicolò. Nova Scientia. Venezia, Stefano di Sabbio, 1537, III.
Drake, Stillman. Tartaglia's squadra and Galileo's compasso, in «Annali dell'Istituto e Museo di Storia della Scienza di Firenze», 2, 1 (1977), pp. 35-54.

Existing Instruments

Florence, Museo Galileo. Institute and Museum of the History of Science, inv. 659.
Florence, Museo Galileo. Institute and Museum of the History of Science, inv. 1303.
Florence, Museo Galileo. Institute and Museum of the History of Science, inv. 1485.

Links (External)

http://catalogue.museogalileo.it/indepth/GunnersQuadrant.html

Images

Niccolò Tartaglia. La noua scientia. Venezia, 1550.	Niccolò Tartaglia. La noua scientia. Venezia, 1550.	Luis Collado. Prattica manuale dell'artiglieria. Milano, 1606, p. 110.
Nicolas Bion. Traité de la construction et des principaux usages des instruments de mathematique, Paris, 1725, tav. 18.