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Description: | LO.121, (old departmental catalogue number in aluminium paint). 50. ( Kelvin bequest number in white cellire). MANU Unsigned. Mid 19th century
[ENGLAND] DES after NICOL,William,Professor. 1838 Edinburgh, Scotland. For the demonstration of bi-refringence and interference patterns. The overal size of each instrument is 167mm x 66mmx 38mm, They are contained in a red velvet lined, brown fish skin covered wooden box. The specimen holder is a wooden disc with 7 round spaces ocupied by 6 specimens and a blank. The disc is rotated between 2 crossed Nicols of tourmaline. On loan to the Physics and Astronomy Department EXIT NUMBER 2092 it is object 6 in display case A Kelvin & 'The New Professors', in room 470, The Kelvin Building, Department of Physics and Astronomy Glasgow University.
Described in the RLS project as
This pair of mid 19th century hand-held polariscopes were used for the demonstration of birefringence and interference patterns. The specimen holders are wooden discs each with seven diaphragms occupied by six specimens and a blank. The disc is rotated between two crossed Nicols made from crystals of the mineral tourmaline.
In 1838 William Nicol invented a prism which polarized light constructing it from two rhombs (blocks) of Iceland spar (calcite) glued together with Canada balsam (a clear resin). Polarization is a process in which light interacts with matter and is rotated. The amount of rotation that occurs is characteristic of the material through which the light has passed or the surface from which it has been reflected.
William Nichol also invented a means of analyzing rock specimens by examining them in transparent thin sections. Initially he used his sections to examine the internal structures of fossil plants. However, with the invention of his prism he was able to identify the individual crystals of which rocks are composed. Nicol prisms soon became indispensable components of geological microscopes. | License: | http://www.hmag.gla.ac.uk/spirit/rights/ | Publisher: | Hunterian Museum and Art Gallery, University of Glasgow | Rights holder: | Hunterian Museum and Art Gallery, University of Glasgow | Subjects: | SCIENTIFIC COLLECTION : | Source: | Hunterian Museum | Creator: | Hunterian Museum and Art Gallery, University of Glasgow | Identifier: | http://www.huntsearch.gla.ac.uk/cgi-bin/... | Language: | en-GB | Go to resource |
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