Jimmy stared fascinated by the hairspring-wheel : he could hardly believe such a tiny spring could ever be made, let alone act as if it were alive , coiling and uncoiling. Spinning first one way , slowing , then the other way , driving the tiny notched wheel that measured out the ticks of the timepiece. He looked in boyish wonder at the the great mainspring which did not seem to move: it was releasing its pent up energy slowly like a great dam of water might drive a turbine wheel.The only outlet of power the mainspring had was the hairspring- wheel which slowly sapped its energy until the next wind up was necessary.
‘What’s that tiny screw on the top of the hairspring wheel Grandfather? Jimmy gazed up into those old grey knowledgeable eyes. The old face wrinkled in smiles ‘ Its the spring adjuster and alters the time-keeping of the watch making it fast or slow’. The boy gazed again lost in wonder and Grandfather clicked his pocket watch shut.
‘ Come ‘he said , ‘ it’s time for lunch’.