This brass trough compass dated 1918 was made by C. Haseler & Son for use by the British Military during WW1, and is engraved'C. HASELER & SON Ltd, II, 4777, 1918' with a military crowfoot arrow on the side. Not used as a traditional compass and known also as a plane table compass, it was used by surveyors to establish the direction of magnetic North when aligning a plane table or theodolite.
The needle of the compass consists of a long narrow magnetised bar of steel, pointed at both ends, with the usual gemstone bearing at its centre for reduced friction. In excellent condition and housed in a mahogany case with a sliding lid that activates a transit lock for when the instrument is not in use. Measuring 165mm x 39mm x 28mm, it weighs 294 grams and is in good working order. Please study the photos as they are part of the description, and I will be happy to answer any questions if I can. Please check out my other auctions for more interesting items.