Two-cylinder brass pump mounted on a kind of tower. Its construction is attributed to Giovanni Albrici (1743-1816), the first machine operative of the Collegio Mariano Physics Cabinet, between 1791 and 1793. Recent restoration work has revealed details concerning Albrici’s construction.
The pump sucks in air from the bell placed on the upper plate, due to movement of the pistons contained in the cylinders; the pistons’ motion mechanically activates the opening and closing of the valve, differently from older models, in which valve opening is determined by pressure difference. A pressure gauge mounted on the side that is connected to the inside of the glass bell shows the degree of rarefaction of the air reached in the bell.
As well as producing a vacuum, Albrici’s pump – as he himself stated in letters sent to Lorenzo Mascheroni – is also able to compress the air inside the bell, which in this case must be firmly held by the wooden frame mounted on the top shelf of the pump.

La pompa pneumatica del Collegio Mariano di Bergamo, (Serra L., Giatti A., Brenni P.) in Esposito S. (a cura di), Atti del XXXVI Convegno Nazionale della Società Italiana di Storici della Fisica e dell’Astronomia (Napoli 04 – 07 ottobre 2016). Pavia University Press, 2017

Restored in 2017 by Paolo Brenni and Anna Giatti in the Fondazione Scienza e Tecnica laboratory in Florence.
Device on display.