Ancient and Medieval Timekeeping

Abstract

Knowing in theory how to solve the problem of longitude by timekeeping, and implementing this solution were two different things. The fundamental problem was the lack of an accurate and reliable timekeeper. This problem had cultural, scientific, and technical dimensions. Time measurement, as distinct from timekeeping, could not occur until people thought time was something measurable. That is, time measurement depended upon an understanding of time as an independent variable, and as something with metric (measurable) properties. This understanding emerged late in human history. Indeed it did not crystalize until the 16th century, and then, it seems only in Europe. Galileo’s law of fall, where he related distance traversed in free fall to the square of the time elapsed (s ∝ t²) is arguably the first clear statement of time as an independent quality, being related to another as a dependent quality.