Take a nineteenth-century diary, handwritten, stitched and cobbled together from other blank notebooks to suit the author’s purpose, bound with rough cloth. At some stage the rats and mice have got at this diary, nibbling away at corners and edges, through quires and cover, perhaps taking the soft shavings away to line their nests. Rat droppings a century old sit in the gutters between sections. Sentences go unfinished. We will never know exactly what the author did on Tuesday the third of September – or the fourth, fifth, sixth, or any of the days through to Christmas.