Article published in the «Daedalus» — 2003 — Vol. 132 — No. 2. On Time (Spring) — pp. 20-26.Almost all cultures and civilizations have concerned themselves with time, if only to give cues and set bounds to social and religious activity. To these ends, they have relied principally on repetitive nat- ural phenomena - on the movements and changing lineaments of heavenly bodies. Such clues are not regular in occurrence nor identical from one to another point of observation. They are sufficiently so, however, for most practical purposes. The more technologically advanced societies have gone beyond passive ob- servation to create instruments of time measurement - what we call clocks.
These initially relied on the observation and measurement of an artificially created regularity - a gravity-driven falling column of water or sand, for example. Such instruments can provide a fairly accurate measure, though they do not afford identical comparisons among themselves and require painstaking attention by way of refilling the chamber and restarting the process. Resetting the clock requires an accurate standard that takes account of seasonal variations, and, insofar as this standard may be the sky, may require such associated tools as a telescope and a little bit of luck in the way of good visibility. It was this uncertain visibility that may have pushed European time-watchers to invent a mechanical clock.
