The Clock With No Face, Only a Voice

Salisbury Cathedral's iron clock has no dial and never did. Built around 1386, it was designed to do one thing: strike a bell on the hour, loud enough for the close and the town beyond it to hear. There was no need to look at it. You listened.

Its mechanism is a frame of wrought iron held together with wedged tenons, driven by two heavy stone weights and regulated by a verge escapement: the alternating catch-and-release that let the gears advance one tooth at a time, at a steady pace, rather than spinning freely. On top of the verge sat a foliot, a swinging bar with two weights that could be slid inward to speed the clock up, or outward to slow it down. A keeper checked the time against a sundial and adjusted the weights by hand whenever the clock drifted, which weather and worn oil made often.

The clock has moved more than once, from a bell tower demolished in 1790, eventually into the cathedral itself, and its verge and foliot are not original: they are a 1956 reproduction, replacing a pendulum added in the 1600s.

Whether it is truly the oldest working clock in the world is genuinely disputed; Wells, Rouen and Beauvais all have claims of their own. What isn't disputed is what the foliot represents: one of the first mechanical devices to break time into discrete, regular beats, the same job a watch's balance wheel, its own small rocking weight, still does several times a second.