Working model
Opera Laboratori Fiorentini

In paragraph LII of the Pneumatics, the Alexandrian scientist Heron (1st century A.D.) describes the construction of a special kind of siphon placed inside a rython, topped by a glass cover MN. At the base of the cover are two small holes, H and F, from which depart two pipes: HK, terminating inside the tank, and FG outside of it. A small hole is pierced in the handle, into which is inserted tube XD, through which water is led into the tank.
When the rython is filled with water through this aperture, pipe HK also fills until water flows out of it, as can be seen through the transparent glass cover MN, through which the water gushes out like a fountain, then descending again through hole F. This demonstrates the effects of a siphon capable of drawing a fluid upward until it reaches the glass cover. Having reached the top of its course, the water and the air contained in the cover are channeled into the second pipe, where they begin to descend.