Accession No

1462

Brief Description

air pump, by George Adams Snr., English, 1740 (c)

Origin

England; London; Fleet Street; Tycho Brahe's Head

Maker

Adams, George (Snr.)

Class

physics

Earliest Date

1740

Latest Date

1740

Inscription Date

Material

metal (brass, steel); wood (mahagony, another); ivory; hide (leather)

Dimensions

length 520mm; breadth 327mm; height 535mm

Special Collection

Provenance

Purchased in 1952.

Inscription

‘MADE by GEO: ADAMS Mathematical Instrument Maker
at TYCHO_BRAHES_HEAD in Fleet_street. LONDON.’ (ivory plaque on front)

Description Notes

Mahagony base with 6 turned mahagony pillars, each with brass knob to square mahagony stand. Two brass pillars at front contain pumps driven by cogged shafts and crank with wooden handle. Pumps each marked ‘H’. Tube from pumps to centre of brass stand for attachment of bell jar or Magdeburgh hemispheres. Small circular brass stand at back of base would origianlly have carried a narrow glass jar. 2 valves on the tubing. Separate handle (for magdeburg hemisphere?) butterfly screw.

incomplete (bell jar missing)

References

Events

Description
In 1647 Otto von Guerricke of Magdeburg invented the first vacuum pump. Guerricke was a physicist, engineer and natural philosopher. His intention in creating the vacuum pump was to study vacuums and the role of air in combustion and respiration.

The vacuum pump is in principle a relatively simple instrument. As the handle is turned the pump moves up and down and the air in the bell jar is evacuated and a partial vacuum is created.

A perfect vacuum is a space with no matter in it. However, a perfect vacuum has never been obtained, the most complete man made vacuum had approximately 100,000 gas molecules cc, compared to 30 billion billion in air at sea level. It is estimated that in space there is roughly one molecule per cubic meter.

A famous early demonstration of a vacuum was that carried out by Otto von Guerricke in Magdeburg. A vacuum pump evacuated air from the inside of two hemispheres that had been placed open edge to open edge. Two teams of eight horses were then attached to the hemisphere handles but failed to pull apart the “Magdeburg” hemispheres.

Created by: Boris Jardine

FM:42655