Ptolemy used this sixty-unit system for subdividing the circle, and he also used it to divide the day. Not until much later, perhaps in the thirteenth century with the arrival of the mechanical clock, did the minute become a division of the hour. The language, again, is a clue to the needs and capacities of timekeeping machinery. The “second” was at first an abbreviation for “second minute,” and originally described the unit resulting from the second operation of sexagesimal subdivision. Long used for subdivisions of a circle, seconds were not applied to timekeeping until clockmaking was
...more
