Not on display
As set out under folio 7 verso (D12134), there are nearly thirty pages of cloud studies in this sketchbook, some annotated with colours, as here, and other observations. This one was made with the page turned vertically. The rough strokes towards the bottom may indicate rain.
There seems to be no sign of John Ruskin’s usual red ink foliation; there are such numbers on most of the later pages (see the Introduction to the sketchbook).