Prepared in connection with his lectures as Professor of Perspective at the Royal Academy, these three diagrams of a square within a circle and circles within squares are based on an illustration representing Propositions 6, 7, and 8 from Book 4 of Samuel Cunn’s Euclid’s Elements of Geometry (London 1759). Beginning from the left, the first figure shows Proposition 6: ‘Problem. To inscribe a square in a given circle’. The next represents Proposition 7: ‘Problem. To describe a square about a given circle’. The last illustrates Proposition 8: ‘Problem. To describe a circle in a given square’.1 There are pencil sketches of each in Turner’s lecture notes.2
Blank, save for an inscription by an unknown hand in pencil ‘16’ bottom left.
Supported by The Samuel H. Kress Foundation