air pump
Date: 1870-1890
Inventory Number: 1996-1-0459
Classification: Air Pump
Subject:
Maker: E. S. Ritchie & Sons (founded 1867)
Cultural Region:
Place of Origin:
Dimensions:
74 × 74 × 30.3 cm (29 1/8 × 29 1/8 × 11 15/16 in.)
Description:
The air pump consists of a single barrel on top of which a long rod connects the piston to the lever. The latter is supported by a turned column. There is also a small mercury cup (to prevent air leakage) and a short brass cylinder. Once the latter has been removed, a barometer and siphon gauge could be added to the pump (missing here). The lever is decorated in gold line motifs. The barrel is connected to a brass tube to the vacuum plate. A thumb screw (stopcock) controls the flow of air to the plate. On top of the plate, covered in glass, there is a perforated thumb screw that let air come into the glass bell jar that would have sit on top of the vacuum plate. The whole apparatus is supported by a wooden board (either mahogany or rosewood) on four turned feet.
Signedon plaque, in script: E. S. Ritchie & Sons / Boston
FunctionAn air-pump is an instrument used to produce a vacuum in order to study nature under controlled environmental conditions. It became one of the most important scientific instruments of natural philosophy as early as the late seventeenth century. With the electrostatic machine, the air-pump became in time not only a genuine research tool but an important pedagogical apparatus in the lecturer-demonstrator's arsenal. Ritchie, as most instrument makers, sold several kinds of these, ranging in price from $10 to $300 in the middle of the nineteenth century.
In this model, a glass bell jar would have been put on the plate. The experiments would have taken place inside the bell jar.
This is how Ritchie introduced his air pumps in 1855: "As so many experiments depend on the perfection of this instrument, I have spared no expense in my machinery for making every part in the most perfect manner. I have introduced some improvements in its construction. My pumps are made on the principle of Leslie, but much improved."
In this model, a glass bell jar would have been put on the plate. The experiments would have taken place inside the bell jar.
This is how Ritchie introduced his air pumps in 1855: "As so many experiments depend on the perfection of this instrument, I have spared no expense in my machinery for making every part in the most perfect manner. I have introduced some improvements in its construction. My pumps are made on the principle of Leslie, but much improved."
Primary SourcesEdward S. Ritchie, Illustrated Catalogue of Philosophical Apparatus (Boston, 1855), 3.