Agnisterion

Instrument, which Heron describes in his work Pneumatika (A,32) and is considered to be the predecessor of the modern tap. It is combined by three homoaxial cylinders, adjoined air-tightly, each bearing a hole. The target is, by moving the cylinders, for all three holes to coincide, when a certain amount of water is provided. The device was used to provide an amount of holy water to the faithful, who came to the temple, so as to spray themselves and be purified, hence the word «Agnisterion».