exit forum, leaving draining the water from a recipient in which the water level was constant. The water outflow, that depends from the pressure, became constant, too. The solution used shows that some of the ideas that will be formalised by Archimedes in his treatise About the floats have already been acquired. A second problem was constituted by the exit forum surface variation due to chalky corrosions or formations. To avoid them Ctesibius realized a gold forum and another one into a gem. The time wasn’t directly showed by the water level, but by a hand revolving on a dial mechanically linked to a float that followed the increasing of the water level. These clock could also include other different mechanisms, such as ringing or robotic movements that came into action at prefixed times.
Technology and Production The hydraulic organ: it was also the first musical instrument with a fingerboard of the history and it was also the first that was scientifically planned. In the organ, which is described by both Vitruvius and Hero, the water presses the air contained into a tank, which is pushed into the canes. The tank is always provided by air thanks to one or more pumps, already described. The water function is to mantain the pressure constant into the tank during its working. In a type described by Hero, the pump is actioned by the wind power, thanks to a mechanism similar to that used into the windmills. Ctesibius gave to his instrument the name of hydraulis (Ύδραυλις), composed with the roots of ὕδω ρ (water) and αὐλός (flute), from which derived the adjective hydraulic, initially used only for the organ and then extended to object without references to the music. The hydraulic organ continued being used, without substantial innovations, during the imperial and Byzantine ages and entered in Europe when the Byzantine emperor Costantine V offered an instrument like that to the king of Franks Pepine the Short.
BIBLIOGRAPHY F. G. Lo Porto, L’attività archeologica in Puglia, in Atti del X Convegno di Studi sulla Magna Grecia (Taranto 1970), Naples, 1971; E. M. De Juliis, L’attività archeologica in Puglia nel 1982, in Atti del XXII Convegno di Studi sulla Magna Grecia (Taranto, 1982); P. Bruni, APVLUS, Tra uomini e fatti di Puglia, Scorpione Editrice, Taranto, 1997;