Note 44 — Chapter XIII · ALCIBIADES.

It is convenient in a narrative to speak of “hours,” and the Greeks had a division of time that was so named. But it must not be supposed that these hours were exact periods of time such as we mean by the word. The day between sunrise and sunset was divided into twelve equal parts, which varied in length according to the season of the year. The divisions of the whole period of a day and night into twenty-four equal unvarying parts was later than the period of which I am writing, being attributed to Hipparchus, the astronomer, a native of Nicæa in Bithynia who lived in the second century B. C. The water-clock mentioned in the text may have been one of those large ones which served for the whole night (Plato is said to have had one). The slave in announcing to the guest the time at which the meal would be served would probably indicate it by pointing to this or that division marked upon it. The water-clock may be roughly compared to a sand-glass, but the water flowed through several orifices, which were very minute.