The whole page is taken up with the following notes:
cannot counteract each other without | supposing each ray [?Eminated] from the Sun | [?to perspective upon ...] the power of [...] | light, but allowing the system of concen | [?trating] light or [?concentrary] light | each ray must pass each other and | therefore tend to destroy what must | give as many shadows and what on | the water is on the other hand con[...] | on glass it would imply some con- | [...], and see the rays of the sun | are as wide as the Sun on the water | but we do not and it is inverted like | the moon visage but in casting an | inverted reflection makes it approach | theoreticly to the Theory of glass which would | inverted the likeness of every objects to our | vision, [?if rather adding] to the [...] of
The passage is part of a sequence of notes and diagrams which runs back from folio 79 verso (D07487) to folio 72 verso (D07473). The previous page of notes is folio 77 verso (D07483), and the next is folio 75 verso (D07479); there is a diagram on the recto of the present leaf (D07480), to which the text is related. The semi-diagrammatic drawing of a boat on folio 81 verso (D07491) also appears to belong with these notes, concerned with sunlight or light in general in terms of reflections and the casting of light and shadow from polished objects or bodies of water. They relate to Turner’s fifth Royal Academy perspective lecture, on reflection and refraction.
Davies 1994, p.289.