Daniel’s gaze fell on a great leather wallet, gnawed at the corners by rodents, but still intact. He unwound the ribbon that held it closed, and spread it out on the lid of a trunk. It was a stack of foolscap sheets rising to the thickness of three fingers, creased and compressed from long immurement, but still perfectly legible. It contained notes, written in Hooke’s hand, and illustrated with more admirable diagrams, on divers subjects: