Caption:
Quadrant showing the "Nonius", which applies a theory of the Portuguese mathematician Pedro Nunes (1502-1578). Replica of the original made by James Kynuyn (ca. 1595) exhibited in the Museo Galileo in Florence, fitted according to the drawing published by Robert Dudley in the book Dell' Arcano Del Mar, 1646-1647. Maritime Museum. Lisbon, Portugal.