Prepared in connection with his lectures as Professor of Perspective at the Royal Academy, Turner’s diagram is based on an illustration from Samuel Cunn’s Euclid’s Elements of Geometry (London 1759, Book 12, Plate 1). It represents Proposition 2 from Book 12: ‘Theorem. Circles are to each other as the squares of their diameters’.1 There is also a pencil sketch of the Proposition in Turner’s lecture notes.2
Blank, save for an inscription by an unknown hand in pencil ‘4’ bottom left.
Supported by The Samuel H. Kress Foundation