Prepared in connection with his lectures as Professor of Perspective at the Royal Academy, Turner’s diagram is based on illustrations from Samuel Cunn’s Euclid’s Elements of Geometry (London 1759, Book 4). The top left and right figures represent Proposition 11: ‘Problem. To describe an equilateral and equiangular pentagon in a given circle’.1 The top centre diagram represents Proposition 13: ‘Problem. To describe a circle in an equilateral and equiangular pentagon’.2 The bottom left diagram represents Proposition 14: ‘Problem. To describe a circle about a given equilateral and equiangular pentagon’.3 The bottom centre diagram seems based on Proposition 15, which is illustrated in another diagram (Tate D17002; Turner Bequest CXCV 32), while that at bottom right is untraced. There are pencil sketches of each in Turner’s lecture notes.4
Blank, save for an inscription by an unknown hand in pencil ‘56’ bottom left.
Supported by The Samuel H. Kress Foundation