This is the second of two diagrams of St George’s Church, Bloomsbury, prepared by Turner as Professor of Perspective at the Royal Academy. The other is Diagram 6 (Tate D17115; Turner Bequest CXCV 144). Diagram 7 depicts the tower and spire of the church (built by Nicholas Hawksmoor, completed 1731) as seen from the south and at a sharp angle from below. It was used to illustrate Turner’s discussion in Lecture 1 devoted to sculpture, particularly the importance of adjusting the proportions of objects placed high above the viewer.1 Based on notes and sketches made in his Windmill and Lock sketchbook (Tate D07973, D08043, D08046, D08047, D08063; Turner Bequest CXIV 10, 64, 66, 67, 76 verso), the finished watercolour demonstrates how the statue of George I (mistakenly called George II by Turner) would be seen by the spectator at street level; from there, the eye foreshortens the tower and bends the straight lines of the spire.
Maurice Davies suggests that although Turner did not specifically discuss the rules of ‘vertical convergence’, the diagram would have allowed to him to illustrate how vertical parallel lines appear to converge when seen from a distance.2 This is made all the more apparent when compared to Diagram 6 – a more straightforward elevation of the church’s northern facade – which is not as effective in showing the effects of height. With Diagram 7, according to Davies,
there appears to be no consistent system regulating the way in which [the perpendicular sides of the church’s tower] are shown. The side furthest from the picture plane (to the left in the picture) is straight and very nearly vertical. On the other hand, that part of the side at the right that is not hidden by the body of the church, slopes markedly to the left as it rises. The lines representing these two sides are largely straight, but the remaining one (central in the picture) twists rather uncomfortably. It begins its rise from the ground by leaning a little to the right, then changes direction and heads to the left, next giving a definite bulge to the tower before it heads upwards, again to the right.3