A hydrochronometer is a kind of water clock.
In 1867 Fr. Giovan Battista Embriaco, O.P., inventor and professor of the College of St. Thomas in Rome, created a hydrochronometer and sent it to the Paris Universal Exposition of 1867, where it received many prizes. It had the shape of a wooden pinnacle made of cast iron fused as tree trunks, while its four dials were visible from every direction.
In 1873, the Water clock was back in Rome and was placed in Villa Borghese gardens into a fountain realized by the architect Gioacchino Ersoch. It's still placed there and works 24/7.
Wikipedia https://en.wikipedia.org/wiki/en:Hydrochronometer
Address Viale dell'Orologio, Roma 00187, Italy
Coordinates 41°54'42.305" N 12°28'50.607" E