Hornsby Water Sculpture Revitalisation

Designed and built by Victor Cusack, 1993

The sculpture was designed and engineered by Victor Cusack and is constructed of bronze, stainless steel and glass. It is approximately 8 metres tall and weighs 20 tonnes. Titled ‘Man, time and the environment’, the sculpture pays tribute to the beauty of the environment in Hornsby Shire and reminds us of our need to show responsibility to the land around us and how time is of the essence. It was designed to evoke curiosity and fascination.

Clepsydra – the first known man-made clock!

First attested to before 16th century BC in ancient Babylon, the earliest Clepsydras comprised of a simple stationary vessel which slowly fills, overflowing with trickling water at a constant rate. The depth of water in the receiving vessel is a measure of time.

The earliest Clepsydras had sloping sides and were rather inaccurate. Records indicate that the Greeks were probably the first to have more accurate cylindrical vertical Clepsydras common in 4th century BC.

The Greek style Clepsydra inside the sculpture fountain is an original modern version built with updated materials, balancing and counterweighting two tubes in such a way that they over-balance when full to discharge their own water, and return to the vertical filling position when they are empty.

The counterweight is shaped to represent a traditional Greek ram’s head while the top of each tube is decorated with a Greek Hermaphrodite (male and female) head.

The tipping motion occurs when the water filling either tube flows into the ‘forward’ set Greek Hermaphrodite head, thus overbalancing the Clepsydra to empty the water into the pond.

Inspired by a Chinese Water Wheel Clock dating back to 1088-92

This water wheel is a clock! Its design is inspired by a wooden version that was once created by Su Song as part of an observation clock tower in China, during 1088-92. That original clock also managed to rotate its entire observation tower at a speed to keep a crude sundial consistently pointing to the sun!

The water wheel you can see has had time scale, size and materials modified to suit the sculpture. However, it has substantially the same form and operational principle as the original.

The wheel incorporates 20 articulated counterweighted buckets which are normally filled by a tank overflowing with water at a constant rate. As the front filling bucket overcomes a counterweight (a Budda sculpture) it falls and trips a lever connected by a cable to a catch on top of the water wheel to rotate the wheel one bucket space only.

By controlling the rate of water entry, the rotating wheel can be used as a clock.

This Pendulum Clock is undoubtably the largest water-driven pendulum clock ever built

It has the same four second pendulum cycle time as Big Ben, but this one is heavier at 350kg!

The first crude water-driven pendulum clock was designed but never built by the 17th century Swiss Claude Perrault in 1669.

The pendulum clock in the fountain, whilst physically able to function, has become impractical to operate. An electric clock has been added to keep the clock dial accurate.

Instead of numbers, the hours on the clock face are marked by the letters that read “Dare we forget”.

The clock is decorated with various animals to “remind us that we are losing species on our earth due to our sometimes insensitive land use” and aboriginal art forms “as a reminder that Hornsby once maintained a strong tribal population that suffered the same fate as many animals are suffering”.

The pendulum clock supplies water to the Chinese clock and previously controlled the rotation of the pontoon clock and hourly chime.

A clock that floats and can be viewed from above

Roman numerals are positioned around the edge of the pond representing a large clock face when viewed from a bird’s eye perspective.

The entire sculpture is attached to a floating pontoon designed to rotate twice each day. This can be achieved by water pumping underneath the pontoon, swirling around the inner pond in a clockwise direction when viewed from above.

The rotating pontoon is unfortunately required to be fixed in place and hence no longer rotates.

The rate at which the pontoon was designed to turn would normally be regulated by a “catch” device on the pontoon edge that locks into one of the 60 stops secured to the wall of the inner pond.

Every 12 minutes, the catch is designed to be released by a mechanism linked to the pendulum clock allowing the pontoon to rotate until the next stop is reached. A concentration of water (located near the end of the carillon) is designed to be directed outwards towards the Roman numerals pointing to the time of day.

The Carillon – an ancient musical instrument

The chimes that you can see within this fountain replicate an ancient musical instrument referred to as a carillon and will sound music when performed by a carillonist. It was tuned to concert pitch with the help of CSIRO’s Sound Laboratory Scientists and is designed to be played on festive occasions in solo recitals or accompanying an orchestra.

The instrument is played by pulling the handles on the playing frame.

The actual tubes, hammers, configuration of playing mechanism and tuning are all identical to the “Harringtons of Coventry” tubular chimes invented 250 years ago. The carillon frame is a bronze sculptural form rather than a box-like timber frame from the original design.

There are a number of Harrington Chime copies that can be found in churches throughout Australia. However, Hornsby’s set has more notes than any other Harrington set ever built, most of which have six to nine chimes only. Hornsby’s set has 17 notes covering the octave above middle C plus three notes above and the G note below.

This carillon was also designed to chime on the hour thanks to the mechanics of the pendulum clock, however this no longer functions.

Together, the tubes weigh approximately one tonne.