Two-cylinder glass pneumatic pump mounted on a walnut table. The brass pistons that move inside the cylinders are operated by rack rods connected to a bar. When a piston rises, the air contained in the bell is sucked beneath the piston, passing through a valve located at the base of the open cylinder; when the piston descends, the air is compressed and closes the valve at the base of the cylinder, opening another valve contained in the piston itself which allows it to exit. The manometer, a U-shaped tube containing mercury enclosed in a small glass bell, allows the pressure inside the container placed on the pump plate to be measured. The pump is signed by its maker Carlo Grindel (1780–1854), mechanic of the Brera astronomical observatory in Milan.
The coil was restored in 2017 by Paolo Brenni and Anna Giatti in the Fondazione Scienza e Tecnica laboratory in Florence.
Device on display.