Made by Turner in preparation for his lectures as Professor of Perspective at the Royal Academy, this cross on a cube was based in part on a diagram of Samuel Marolois’s technique described in John Joshua Kirby’s Dr Brook Taylor’s Method of Perspective Made Easie; both in Theory and Practice: in Two Books (1768, II, pl.XIX, fig.3). For the drawing, Maurice Davies explains,
there is a horizon line, a base line and a centre line, with the eye/distance point located where the centre line meets the ruled frame of the drawing. Two lines drawn from this eye/distance point give the two vanishing points on the horizon, each near to the left or right edge of the drawing. The measure point corresponding to the right-hand vanishing point is clearly marked, also on the horizon. Various measurements of the object are set off on the base line and, as expected, lines can be found from these to the measure point and the vanishing points.
Davies continues that Turner ‘seems to have carried out a quite lengthy procedure to locate the measure point, but unnecessarily, as it could have been positioned simply by drawing a single arc centred on the vanishing point, from the eye/distance point to the horizon. The diagram contains much further construction that seems superfluous’.
1 Turner may have intended to produce a lecture diagram from a tracing he made of this study, but it was left unfinished (Tate
D17130; Turner Bequest CXCV 159).
The verso, with indications of Turner’s transfer process, is
D40013.
Andrea Fredericksen
June 2004
