page_title: Hornsby Water Clock
section_title: Greek clepsydra clock
hierarchical_section_title: Hornsby Water Clock / Individual clocks / Greek clepsydra clock
caption_attribution_description: English: Hornsby water clock: detail of plaque showing diagram showing general layout of Greek clepsydra.
context_page_description: The Hornsby Water Clock, titled Man, Time and the Environment is a piece of kinetic sculpture, a decorative fountain and a functional clock in the Florence Street pedestrian mall in Hornsby, New South Wales, Australia. Unveiled in 1993, the sculpture was designed and engineered by Victor Cusack and constructed of bronze, stainless steel and glass by Victor and his foundry floor manager Rex Feakes. Construction, including alterations to the mall, cost over A$1 million and took two and half years; thereafter, chicken bones and other carelessly discarded items caused many breakdowns before the water filtration system was upgraded.
context_section_description: In this type of clock, water is run into a stationary vessel from a tank which is kept meniscus-full meaning that water rises over the top edge of the tank forming a convex meniscus and excess water is drained away. Since the depth of the water in the supply tank is constant, water is released at a constant rate; the depth of water in the receiving vessel is a measure of time.
  In this example, two tubes on bearings are arranged so that they overbalance when full, thereby dumping their contents into the pond and returning to vertical under the influence of a counterweight at which point the cycle starts over. The counterweight is in the shape of a ram's head, while the top of each tube is decorated with the head of a Hermaphrodite.
caption: Diagram showing general arrangement of the Greek clepsydra
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