|
Date: |
|
Description: | P 19" ( Period of oscillation 19 seconds) . 7.5 Grams (written in black ink on the back of the bezel). DES THOMSON,William,Lord,1st Baron Kelvin of Largs. after 1876 MANU Kelvin Bottomley & Baird Ltd between 1913 and 1947 16, 18 and 20, Cambridge Street, Glasgow, Scotland. This six inch card is a production model of one of two forms of the dry card. The two types are form a, which has the needle assembly suspended below the plane of the card and form b which has the needle assembly above the plane of the card. In this type form a, the card is supported by a sapphire bearing at the nave on a platinum-iridium needle pointing upwards through the plane of the card . This variant has two pairs of steel needle magnets suspended on green silk threads below the plane of the card, arranged in parallel rows on either side of the nave. The paper bezel is supported by a thin aluminium ring and 16 radial green silk threads attached to the nave which consists of a fine, pierced aluminium disc. The space between the bezel and the nave on this variant is filled, as is GLAHM 105007, with an aluminised overprinted paper disc. The overall size of the box is 80x80x35mm. N.B. The card may be mounted on the bearing and needle and used as a compass by putting the needle in one of the two holes provided, in the base of the box. But when the compass is in storage the North poles of the magnets should always point north. This orientation can be achieved by lining the card and box as shown on the inside of the lid to the magnetic north indicated by the card in the area where it is to be stored. On loan to the Physics and Astronomy Department EXIT NUMBER 2092 it is object 23 in display case D Kelvin & 'the New Professors ', in room 470, The Kelvin Building, Department of Physics and Astronomy Glasgow University. | 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 |
|
|