The right-hand side of the page is taken up with the following notes:
difficulty and therefore master of such | [?truth] continued with mechanicall Hints | of truth of nature perpetualy trammled | with mechanical shackles1
These notes are part of a sequence beginning at folio 53 verso (see entry for D07448) and continuing back through the sketchbook to folio 48 verso (D07438). The previous passage is on folio 50 verso (D07442), and the next on the recto of the present leaf (D07439), continuing in mid-sentence at each end. In his partial transcription, Jerrold Ziff reads ‘of truth’ as ‘of the strength’,2 but this appears to interpolate too many letters.
The diagram to the left has been identified by Maurice Davies as taken from Daniele Barbaro, La Practica della Perspettiva, Venice 1568, page 33; it is one of several copied into the Perspective sketchbook which Turner did not use for his perspective lectures.3 There are four rather crudely-rendered diagrams on the page. Three towards the top show square grids face on and projected above to individual vanishing points, as if they were cubes. The diagram Turner copied from the bottom left is separate from the rest and shows a sqaure grid face on, heavily annotated with letters, and again, receding above and marked with the same letters, this time towards an implied vanishing point to the right. Turner has added spurious lines to the lower right to form a cube, and has not transcribed the letters.
Turner presumably consulted the copy bound with other perspective treatises at the British Museum (since transferred to the British Library, London; see the sketchbook Introduction). There are notes from the same source on folio 5 recto (D07359).
There is some offsetting from the ink inscription opposite on folio 50 recto (D07441).