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Description: | KAG.3. (Green and Lloyd catalogue number) (in white paint). E. 162 ( old departmental catalogue number in black cellire). J. WHITE GLASGOW. MANU J. White. circa 1884 16, 18 and 20, Cambridge Street, Glasgow, Scotland. DES THOM and GRAY After 1884 DES after SCHWEIGGER,Johann,Salomo,Christoph. 1820 Halle, Germany. DES after NOBILI,Leopoldo. 1825 Florence, Italy. This instrument is a low resistance moving magnet mirror galvanometer with four fixed coils offset to ensure uniformity of the magnetic field. There were two astatic pairs, one of which is missing, that were made up of two shaped needle magnets supported on an aluminium frame, and enclosed in both of pairs of coils. The mirror was supported by the same frame or the suspension. There is a control magnet, placed above the coils on the outside of the case to compensate for the earth's magnetic field and any other extraneous magnetic influence. In this way the instrument can be orientated in any position and zeroed by moving the magnet. This form of the instrument was devised by Thom and Gray and reported in the Proc. Roy. Soc. 1884. N.B. Green and Lloyd assumed that the Gray was Kelvin's assistant and successor Professor Andrew Gray. This may not be the case . The discovery of the astatic pair is attributed to Professor Cummings of Cambridge and improvements to the arrangement were made by Leopoldo Nobili , Ann. de Chemie et Phys. T.XLIII, 1830. | 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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