Accession No

2038

Brief Description

air pump, by the Pulsometer Engineering company, English, 1/2 20th C

Origin

9 Elms Iron Works; Reading; England

Maker

Pulsometer engineering company

Class

physics

Earliest Date

1900

Latest Date

1950

Inscription Date

Material

metal (cast iron, brass); wood; oil

Dimensions

length 400mm; breadth 320mm; height 520mm

Special Collection

Cavendish collection

Provenance

Transferred from Cavendish Laboratory, University of Cambridge, 1974.

Inscription

‘PULSOMETER ENGG CO LTD
9 ELMS IRON
WORKS
READING’ (plate on base)

Description Notes

Vacuum / air pump, by the Pulsometer Engineering company, English, 1/2 20th C.

Rectangular black-painted cast iron base carries brass piston and iron standard which carries arm which moves inner part of piston; driven by fly wheel with wooden handle. Stop cock on piston, also short pipe for connection to item being evacuated.

Condition fair; complete.

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:44782