The alarm clock of Plato
(the first awakening device in human history)
Plato
Greece, around 428-348 BCE
The upper ceramic vessel supplies the next vessel through an (appropriately calculated for every case) outflow funnel.When the second vessel becomes full at the programmed moment (for example after 7 hours) through the internally located axial pipette, it evacuates fast towards the next closed vessel and forces the contained air to come out whistling through a tube at its top.After its function, the third vessel empties slowly (through a small hole located at its bottom) towards the lower storage vessel in order to be reused.
https://youtu.be/J-ZWl6Lx7lA
Reference