Accession No

1970


Brief Description

3 glass discharge tubes, 1875-1925


Origin


Maker


Class

physics


Earliest Date

1875


Latest Date

1925


Inscription Date


Material

glass; metal (silver, copper, aluminium, white metal); wax


Dimensions

1970.1 length 480mm; beadth 120mm; thickness 35mm; 1970.2 length 375mm; breadth 120mm; thickness 40mm; 1970.3 length 445mm; breadth 103mm; thickness 40mm


Special Collection

Cavendish collection


Provenance

Transferred from the Cavendish Laboratory, University of Cambridge, in 1974.


Inscription


Description Notes

3 blown glass vacuum tubes in form of triple S with spherical chambers joining each semi-circle.
1970.1 has silvering on internal faces of end spheres

Condition good; complete


References


Events

Description
Glass has been prized for centuries for its transparency and moldability. It’s these qualities that make it one of the most important materials in the history of physics. The Whipple cares for a large collection of glassware from the University of Cambridge’s Cavendish Laboratory of Experimental Physics.

Most of it dates from the 1880s to the 1930s, when Cavendish Professor J.J. Thomson and his students were studying the mysterious glows and rays that can be seen through the glass when electricity is run through a gas in a partial vacuum. These studies led to Thomson’s discovery that cathode rays were made up of sub-atomic negatively charged particles in 1897. He named them corpuscles: we know them as electrons.

The Laboratory’s technical team included gifted glassblowers. They created and repaired the intricate vessels to order: whatever the researcher needed for his or her experiments.

Many of the technicians joined the Laboratory as young boys and remained there throughout their careers. This meant there was an unbroken continuity of craft and technical knowledge across the Laboratory’s first six decades.

Scientific glassblowers work with prefabricated tubes of set diameters and thicknesses. They use a flame and their own breath to expand and bend them into the shapes needed for each experiment.

At the Cavendish Laboratory, all students were encouraged to learn glassblowing, but it was very difficult to master.

“Only those who have tried it know how exasperating glass-blowing can be, and how often when the apparatus is finished it breaks and the work has to be begun again.”
J.J. Thomson, Cavendish Professor, 1936

These intricate forms were blown and shaped using standard glass tubing. It would take the craftsman about half a day using a pump to remove the air from one tube. It might then be filled with a specific (sometimes hazardous) gas, such as helium. It contains metal terminals to enable an electric current.

10/07/2025
Created by: Hannah Price on 10/07/2025


FM:40453

Images (Click to view full size):