Torricelli
This sculpture shows water under hydrostatic pressure, which fascinated the 17th century Italian physicist, philosopher and mathematican Evangelista Torricelli.
This is the pressure that comes from the head or the distance between the surface of the water and a point below, regardless of the volume of water. A pool on high ground overlooking the Serpent Garden overflows to fill up the sculpture below through underground pipework. The water rises in the transparent tubes until it is level with the surface of the nearby pool, representing the head of water that has been reached.
A pneumatically powered valve below the ground opens to release the hydrostatically charged water into a circular manifold that feeds ninety jets that leap vertically up and then gradually subside in unison with the dropping levels visible in the transparent tubes. When these jets have all but died the valve closes, allowing the system to fill up again and the cycle to continue.