Beginning of Essay
The clock is one of the most influential discoveries in the history of western science. The division of time into regular, predictable units is fundamental to the operation of society. Even in ancient times, humanity recognized the necessity of an orderly system ....

Middle of Essay
.... with the Clepsydra and the celestial sphere, humanity was capable of creating more practical and accurate devices for measuring time—the anaphoric clock and the astrolabe. Although Ptolemy was familiar with both the anaphoric clock and the astrolabe, I believe that the development of the anaphoric clock preceded the development of the astrolabe. The earliest example, in western culture, of a celestial sphere is attributed to the presocratic philosopher Thales. Unfortunately, little is known about Thales’ sphere beyond Cicero’s description in the De re publica: For Gallus told us that the other kind of celestial globe, which was solid ....