Once she passes the neck, her work becomes easier. Bodies are a different language. Shoulders with epaulettes, the coat-tails, moving down to the breeches and the lead foot, always cut dead flat. This naval officer must be fresh home. He is not supposed to wear his uniform on furlough. It is a rare sighting, a gift; a glimpse, however tenuous, of a happier time.

Wind gusts. The trees cast their treasuries of gold and bronze down upon the men and an oak leaf, crisp and brown, sticks upright in the rim of the cocked hat. It would be a beautiful detail to include, if Agnes had not cut that shape already.

She moves on to the final curve, the one she must not rush, even though her knuckles are beginning to cramp and … there. The shade emerges from its background, triumphant. Another puff of wind snatches the waste sable paper and sends it, spiralling, into the leaden sky above.

Agnes frowns at her work, dissatisfied. She has overdone the nose and underplayed the chin. This is a nuance people rarely understand about her art: a shadow, an exact replica of the shade a person casts, possesses next to no likeness at all. It must be honed and exaggerated before they will recognise the profile as their own. But she does not have time to make changes. The group of gentlemen are taking their leave. Clouds pillow fast behind the limestone of the old Sydney Hotel.

For all her talent, Agnes cannot work in the rain. It is time to return home.

She plods these days, a legacy of the Accident. Or perhaps she is just getting old. Bath’s streets seem harder to navigate, and the soles of her half-boots slip whenever there are cobbles underfoot. Umbrellas sprout, making the crossing at Pulteney Bridge an ordeal of twice its usual bustle. Damp woollen coats press against her. The kennels run fast in the rain, carrying the odours of horse muck and sewage.

Surely it never used to be like this?

The Bath of Agnes’s childhood was a city of palaces. People came for the cure, of course, but they were not all invalids in Merlin chairs back then; the fashionable paraded in the Pump Room by day and danced in the Assembly Rooms by night. There was always a play or a concert in some white stone mansion.

Now carbon deposits have stained the buildings, giving them a funeral aspect. Dirt bleeds into the river, into the sky. The soul of Bath has left and its body is decaying. Only the Somerset hills glow in the distance, preternaturally vivid.

A horsewhip cracks the air. Agnes pulls up short on the edge of the pavement, just in time. A great cart lumbers past, its wheels squeaking, and splashes her skirts.