![Carrying case for sighting attachment](https://coimages.sciencemuseumgroup.org.uk/303/754/large_smg00064386.jpg)
Carrying case for sighting attachment
Carrying case for sighting attachment, patt.57, for compass with Kelvin's Azimuth mirror replaced with prism, unsigned, 1883-1939
Sighting attachment, patt.57, for compass with Kelvin's Azimuth mirror replaced with prism, unsigned, (1913-1939). Based on William Thomson, Baron Kelvin's 1883 patent.
Carrying case for sighting attachment, patt.57, for compass with Kelvin's Azimuth mirror replaced with prism, unsigned, 1883-1939
Sighting attachment for compass, patt 57, No781