History of Science Museum: Collection Database Search

Record Details

X-Ray Tube with Trolley, Bobbin and Line, by or for H.G.J. Moseley, Oxford, 1914

preview image for X-Ray Tube with Trolley, Bobbin and Line, by or for H.G.J. Moseley, Oxford, 1914
Object is on display.
Inventory Number: 30436
Object Type:
Persons: Henry Gwyn Jeffreys Moseley
Date Created: 1914
Place Created: Oxford England United Kingdom Europe
Accession Number: 1935-8
Brief Description: These pieces of apparatus were constructed for or possibly by Henry Moseley. He used them at Oxford from early 1914 onwards to study chemical samples using X-ray spectroscopy and hence determine their atomic number. These experiments were begun in Manchester in 1913 and continued in Oxford through to mid-1914. The results were published in the ‘Philosophical Magazine’ in 1913 and 1914.

Moseley used X-rays to analyse the properties of elements in a new and brilliant way: he generated characteristic X-rays of sample elements and analysed them in the spectrometer. Moseley placed the specimens he wanted to investigate in an X-ray tube and created a vacuum by evacuating air from the X-ray tube and spectrometer. He made use of the effect that when an element is bombarded with energetic electrons X-rays with characteristic wavelengths are produced. These different wavelengths led to the X-rays being reflected at different angles from the crystal in the centre of the spectrometer. So when X-ray beams of different wavelengths hit a photographic plate they will create distinct lines. The angular position and separation of these lines are unique for each element. These values helped Harry to determine the wavelengths of the lines and hence the number of protons in the element’s nucleus.

Moseley also used a trolley bobbin tube used a small trolley to move the target chemical element samples along a 'track', pulled by a cord wound around a brass bobbin. This meant the trolley could be moved without breaking the vacuum and hence the experimental apparatus did not need to be pumped out every time the sample was changed. This was a system of Moseley's own construction and design and meant his scientific experiments could be conducted quicker.

Long glass tube with the attachment at one end now broken off. The cathode has become detached from its glass bulb. The apparatus is likely to date from early 1914 as Moseley's Manchester apparatus broke shortly after he returned to Oxford at the end of 1913. Note that it also seems designed to fit with Inventory No. 17217 Spectrometer, by Charles W. Cook for H.G.J. Moseley, Manchester, early 1914 which was put into operation in early 1914.

See attached narrative 'Henry 'Harry' Moseley and his experiments' for further details.
Provenance: Used by H.G.J. Moseley at the Electrical Laboratory, Oxford
Collection Group:
Material(s): Glass
Cu
Copper alloy
vegetal fibre thread
plastic
Dimensions:
Height Width Depth Diameter Unit
280 60 mm

Narratives

Image with multimedia irn 53687Image with multimedia irn 53688Image with multimedia irn 53689Image with multimedia irn 53690

Permalink: http://www.mhs.ox.ac.uk/object/inv/30436