Museo Galileo
Virtual Museum
Air pump, twin barrels, table-top model
    • Setting:
      Room X
    • Maker:
    • Place:
    • Date:
      ca. 1830
    • Materials:
      mahogany, brass, iron, glass
    • Dimensions:
      total height 520 mm, base 460x400 mm
    • Inventory:
    • Air pump, twin barrels, table-top model (Inv. 3777)

Typical nineteenth-century French air pump, fairly common in physics laboratories until the early twentieth century. Mounted on a wooden base, it is fitted with two glass barrels whose pistons carry racks and are operated by a pinion with two handles. The mechanism is housed in a frame supported by a pair of small brass pillars. A stop-cock at the base of the barrels regulates the flow of air from the bell-jar, which rests on a metal plate covered by a ground-glass disk. In 1827, the Italian physicist Giuseppe Belli invented a special faucet for adjusting the connections between the pistons and the plate so as to obtain a better vacuum. This device was reinvented independently a few years later by Jacques Babinet, whose name is engraved on the faucet. A mercury pressure-gauge or manometer fitted with a second faucet is screwed onto the connection between the plate and the barrels. English-made pumps of this type always had brass barrels, while those made in France generally had glass barrels. Provenance: Lorraine collections.