¹Mr Abelard did not believe in explaining things twice. “Observe,” he would say, holding up some minute brass wheel between finger and thumb, “and remember.” Then he would bend over the bench again, his eyeglass screwed into his face, and the workshop would fall silent except for the ticking of forty clocks, none of which agreed with any other.

²Hannah had been his apprentice for eleven weeks. In that time she had been permitted to sweep the floor, polish the glass of the display cases and, on one memorable afternoon, hold a pair of tweezers while he fitted a hairspring. She had not been permitted to touch a single mechanism herself.

³It was not, she had decided, that he thought her clumsy. It was that he thought everyone clumsy, himself included, and regarded each clock as a small, fragile life that must not be entrusted to anybody who had not earned it.

⁴On the Thursday before Christmas, a boy arrived at the door with a carriage clock wrapped in a scarf. It belonged to his grandmother; it had stopped; could it be mended by Saturday? Mr Abelard turned it over, listened to it, shook it very gently and set it down on the bench with an expression Hannah had never seen before. It was almost, she thought, embarrassment.

⁵“My hands,” he said at last, and spread them on the bench. They were trembling, not much, but enough. “It is the cold. It will pass. But not by Saturday.”

⁶Hannah waited. The forty clocks ticked. Then Mr Abelard took the eyeglass from his own face and held it out to her, and she understood that this was the only explanation she was going to get.

⁷She worked until the windows were dark. The fault, when she found it, was absurdly small: a single hair, caught in the escapement, that had stopped the whole patient business of the wheels. She lifted it out with the tweezers, and the clock, as if it had merely been holding its breath, began to tick.