The whole page is taken up with the following notes:
by the rays of the Sun and the interruption | of those rays by an <...> intervening objects | are parralell but all lights produced | by art and their shadow converge and | diverge to and from a point, tho there | can be no doubt in my mind that they are | the same and the difference produced in | nature is only by the various proportions | of light. Find the proportion of the inter | vening objects to produce shade and [?could] | we but place an object to be illumind or | cast in shade of the proportion in every | respect to magnitude of the O disk we | should conclude them parallel whereas | my young friends must be aware that I | feel disposed to think they [?increase], and | indeed philsopicaly considered I cannot | suppose them otherwise for the Theory of | G. L. principly depends upon the under | parts being always in shade and therefore | the suns rays must be always parall
This passage follows on from the opposite page, folio 91 recto (
D07510), and continues on the recto of this leaf (
D07508). It is part of a sequence beginning on folio 91 verso (
D07511), and running back to folio 82 verso (
D07493). John Gage has discussed these provisional notes (not developed in the perspective lectures) as an example of Turner’s close observation of natural phenomena,
1 in this case the question of sunlight travelling in parallel lines or otherwise, responding to a chapter of
The Art of Painting by Gérard de Lairesse (1640–1711), in the English translation by John Frederick Frisch (London 1738 and later editions).
2 See under
D07511 for a discussion of Lairesse’s text. Maurice Davies has registered Turner’s notes as ‘on light and shadow’, as part of a longer sequence running back to folio 72 verso (
D07473).
3
