A College Science Master and a frog that changed history
24 Nov 2025
An X-ray tube used to produce the earliest surviving X-ray in New Zealand – an image of a frog – has been discovered in the Christ’s College Science Block.
Science Master Dr William Percival Evans took the X-ray while teaching at College in September 1896. College Physics Technician Dr Ian Farrell recently found the tube in a box at the back of the department laboratory following a request from Health New Zealand – Te Whatu Ora physicist Steven Muir to help with his research.
The glass plate image of the frog – identified as Leiopelma hochstetteri – was added to the Canterbury Museum collection in 1883, along with the subject. Both the X-ray and well-preserved frog were recently rediscovered. Dr Evans had sourced the X-ray subject from leading geologist and museum curator Frederick Hutton.
The original X-ray tube is now on display in the College Museum in an exhibition created by Head of Department – Physics David Newton.
Archivist Anne Gabrielsson describes the X-ray tube as “an extraordinary artefact in New Zealand’s scientific history”.
“We are fortunate to have meticulous records in our Archives, including our 1896 Board Minutes outlining the purchasing of science equipment,” she says. “Working with Steven Muir, we realised that this confirmed the value of our discovery in our College laboratory.”
A high-voltage generator, the Wimshurst machine – built by former College Master Edward King – is still in use in the Physics Department. It can be used to power up the original tube.
