Quadrant from 'Margarita Philosophica', London, 1535.
© Science Museum / Science & Society Picture Library
Print showing a diagram of a horary quadrant, an astronomical instrument that can be used to determine the time from the position of the Sun and stars. It is taken from 'Margarita Philosophica' (Pearl of Wisdom), 1535 edition (p 1345), written by the medieval philosopher, Gregor Reisch (1467-1525). This encyclopaedic work contains commentaries on the subjects of astronomy, geometry, anatomy and geography.