A rare Prismatic Pocket Compass by Thomas Cooke & Sons of York, dating from c.1868. This type of compass was a development of Schmalcalder's Patent compass of 1812 which introduced the idea of using an optical prism, combined with a sighting vane, to improve accuracy when taking bearings. This compass has an oxidized brass case with a push-fit lid, green compass card and jewelled pivot, an optical prism and a folding sighting vane. The distinctive bright green card design is very similar to one commonly used by Francis Barker & Son around this time, and was intended to enhance the night marching capabilities of the compass. This type of compass was used by the British Army from around 1860 to 1900. This particular example is very unusual in that it is only 45mm in diameter. Most examples of this type of compass were larger, at around 70mm.
In very good condition and full working order, with just some wear to the original oxidized finish of the case.
Dimensions: 45mm (diameter)
Thomas Cooke (1807-1868): Established his business in a small shop at near York Minster at 50 Stonegate in 1837 and later moved to larger premises in Coney Street. He built his first telescope for William Gray. At that time, the excise tax on glass discouraged the making of telescopes which were usually imported from abroad. Cooke was thus one of the pioneers of making refracting telescopes in Britain. Cooke made many other scientific instruments and in 1855 he moved to bigger premises, the Buckingham Works at Bishophill in York. Thomas Cooke died in 1868 and the business was continued by his sons, Thomas and Frederick. T. Cooke & Sons eventually amalgamated with Troughton & Simms (London) to become Cooke, Troughton & Simms in 1922 and this later became part of Vickers.