The Hymans Pocket Range Finder is a compact optical instrument developed during World War I for estimating distances in the field. It was patented in 1915 by Charles Hymans of Cambridge and officially supplied to H.M. War Office. Designed for use by British military personnel, especially officers and cyclist corps, it allowed users to determine the range to a target using a wedge sighting principle. The device works by aligning two images through its optics and reading the distance from a calibrated scale. It was lightweight, portable, and often came with a leather case and instruction manual. These range finders were essential for artillery accuracy and tactical planning in trench warfare and open-field operations. This is a rare early-production Hymans Pocket Range Finder, marked “Patent Pending” and dating from early 1915. Designed by Charles Hymans of Cambridge and later officially supplied to H.M. War Office, this compact optical device was used by British officers during World War I to estimate distances in the field. Key Features: Date: Early 1915 (pre-patent issue) Inventor: Charles Hymans, Cambridge Function: Optical wedge sighting rangefinder Material: Brass and glass construction Accessories: Includes original leather case Condition: Excellent vintage condition, signs of wear consistent with age Optics intact and functional, although slightly stiff - handle with care Leather case shows minor wear consistent with age