A very early example of the Francis Barker 'Prospecting’ hunter cased compass, dating from 1906. A version of Barker's 'Glow Needle' design, it was patented in June 1906 (Patent No. 12777). The compass has a raised metal graduated ring, luminous N. & S. flat needle, agate cap, side stop, transit lock, and a lid fitted with a magnifying lens. It was described in Barker catalogues as being useful for "examining any object; most suitable for Prospectors and others; can also be used as a burning glass". The compass used an early form of luminous paint, probably something similar to 'Balmain's Compound'. It would have been made luminous by exposure to a very bright light source, such as burning magnesium ribbon close to the dial. The compass has the patent number and the date 1906 engraved on the base, along with the maker's details: 'F. Barker & Son, London'.
An identical example of this type of compass can be seen on p.117 of Paul Crespel's book, Trade Mark London, and at trademarklondon.com.
The compass is in good condition and finds North well. The transit lock is working well. The magnifying lens in the lid is in good condition, with some scratches. The compass needle is in good condition, with some wear to the luminous paint. The case is in good condition. Most of the original oxidised finish of the case has worn away over time.