Science . mselves, impatient for their me the good old time-piece, if you please, Confoimd the villain that invented these! As in Greece so in Rome, the clepsydrafollowed in the wake of the sundial, andas in the ease of the sundial, Grecian sci-ence and genius had by this time produceda much more perfect instrument than thatfirst used by the Greeks. In describing the sundial of Berosus, Istated that by it the day was divided fromsunrise to sunset into twelve parts, varyingin lengths from day to day, called tem-porary hours. If now the clepsydra andthe sundial were to read alike, it
Science . mselves, impatient for their me the good old time-piece, if you please, Confoimd the villain that invented these! As in Greece so in Rome, the clepsydrafollowed in the wake of the sundial, andas in the ease of the sundial, Grecian sci-ence and genius had by this time produceda much more perfect instrument than thatfirst used by the Greeks. In describing the sundial of Berosus, Istated that by it the day was divided fromsunrise to sunset into twelve parts, varyingin lengths from day to day, called tem-porary hours. If now the clepsydra andthe sundial were to read alike, it was neces-sary that the hours recorded by the clep-sydra should also change from day to devices were adopted to accomplishthis. Further, as the clepsydra could beused throughout the entire day and night,it was necessary to have it record hours ofa different length at night from what itdid in the day, as each night, i. e., fromsunset to sunrise, was divided into twelvehours as well as each Fig. 1 represents an early form of theclepsydra. It consists of an inverted coneA, with a small aperture at its vertex. Thewater is supplied through the pipe H andis prevented from rising above a fixed levelin A by the waste pipe I, which carriesoff the superfluous water. Thus there willbe a uniform flow of water from the vertexof the cone into the cylindrical vessel andthe cork F will rise uniformly, communi-cating its motion through the rod E to thehand G, which indicates the hours on thedial. In order to produce a change in therate of flow of the water from the conicalvessel, as is necessary in having the handindicate hours of different length from dayto day, a solid cone B, similar to A, wasplunged into the hollow one, and its posi-tion for any given day or night was indi-cated by the coincidence of a particular oneof the adjusting marks on the stem D withthe top cross-piece of the frame C. A later form of clepsydra, attributed toCtesibius, who lived during the latter pa
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Keywords: ., bookcentury1800, bookdecade1880, booksubjects, booksubjectscience
