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 2). It represents Proposition 15 from Book 12: ‘Theorem. The bases and altitudes of equal cones and cylinders are reciprocally proportional; and cones and cylinders, whose bases and altitudes are reciprocally proportional, are equal to one another’.1
Cunn 1759, pp.267–8.
Blank, save for an inscription by an unknown hand in pencil ‘52’ bottom left.
Supported by The Samuel H. Kress Foundation