This ‘lead-covered’ cloud symbolises the mood of the family as they approach the ‘grim North’, and soon they smell the smoke and see the pollution emanating from the industrialized town of Milton. The cloud turns out to be man-made rather than climatic.
‘For several miles before they reached Milton, they saw a deep lead-coloured cloud hanging over the horizon in the direction in which it lay … Nearer to the town, the air had a faint taste and smell of smoke; perhaps, after all, more a loss of the fragrance of grass and herbage than any positive taste or smell.’
Source: Elizabeth Gaskell, North and South (London: John Murray, 1925), p. 66
