Spectrometer, by Charles W. Cook for H.G.J. Moseley, Manchester, Early 1914
|Inventory Number:|| 17217|
|Object Type:|| |
Charles W. Cook (Maker)|
|Date Created:||early 1914|
|Place Created:|| Manchester England United Kingdom Europe
|Brief Description:||This spectrometer was made by Manchester firm Charles W. Cook and was used by Henry Moseley 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.
Cylinder with lid. Within the cylinder there is an inner and an outer circular degree scale, 0 - . Both are divided to 10, 5, 1, ½, and numbered by 10. The central brass plate has a Vernier scale.
See attached narrative 'Henry 'Harry' Moseley and his experiments' for further details.
|Primary Inscriptions:||Plaque on lid: "CHAS. W. COOK, / Engineer & Scientific / Apparatus Maker, / UNIVERSITY WORKS, / MANCHESTER."|
|Provenance:||Presented by Professor J. S. Townsend
Used by H.G.J. Moseley at the Electrical Laboratory, Oxford|