Lecture Diagram 11: Spheres at Different Distances from the Eye (after Thomas Malton Senior)

This diagram is based on an illustration from A Compleat Treatise on Perspective in Theory and Practice on the True Principles of Dr Brook Taylor (1775, pl.1, fig.3) by the elder Thomas Malton (1726–1801). It provides a model of vision as a cone of rays travelling from various globes towards the eye. Turner used it for Lecture 2 as Professor of Perspective at the Royal Academy. He began this by discussing Malton’s first theorem, which he paraphrases as demonstrating that ‘all objects appear in proportion to their several angles under which they are seen’.1 Turner made sketches of the theorem in both the first draft and subsequent copy of Lecture 2.2

Technical notes:

Peter Bower states that the sheet is Royal size Whatman paper made by William Balston and Finch and Thomas Robert Hollingworth, at Turkey Mill, Maidstone, Kent. He writes that ‘all the group of papers with 1794 dates in the watermark show considerable process dirt and poor formation’. He attributes a lack of quality control to James Whatman’s stroke and the change of ownership at the mill.1

Verso:

Blank, save for an inscription by an unknown hand in pencil ‘167’ bottom left.