A description of this device may be found in the “Catalogo metodico” inventory of the Liceo Sarpi.
‘Operational model of an aspirating pump to be used not only in the air, but also in a vacuum to show that in the latter case it no longer performs its usual function. Consists of three parts: 1^st the trumpet itself, made of glass and brass; 2^nd a glass tube with very thick walls and smooth edges; 3^rd a wooden frame’.
Water intake is only possible because the piston’s action produces a pressure lower than the atmospheric pressure that acts on the water, without which the phenomenon could not occur.
Device on display.