An early example of the Francis Barker 'Prospecting’ compass, dating from 1906. It was a version of Barker's 'Glow Needle' design, which was patented in June 1906 (Patent No. 12777). The Patent number and the date '1906' are stamped on the base. The compass has a raised graduated ring, luminous painted flat needle, agate cap, side stop, and transit lock. The lid is fitted with a powerful magnifying lens, described in Barker's 1909 catalogue as being useful for 'examining any object; most suitable for Prospectors and others; can also be used as a burning glass'.
The luminous paint used in this compass was most probably a version of 'Balmain's Luminous Paint', a compound of calcium sulphide, which was made luminous by exposure to sunlight or by burning a strip of magnesium ribbon near the compass. It was patented in England by William Balmain in 1877, and was often used in compasses during the last quarter of the 19th century.
An identical example of this type of compass can be seen on p.183 of Paul Crespel's excellent book, Trade Mark London, available to view as a PDF at trademarklondon.com.
Condition:
The compass is in very good condition and finds North well. The transit lock is working well. The magnifying lens is in very good condition, with a couple of minor marks. The needle is in very good condition. The brass case is in very good condition, with a few marks, and some wear to the original bronzed finish.
Dimensions: 48mm diameter (65mm inc. loop)
