Balloon Observer’s/Early RFC Mapholder/Rangefinder. A very interesting example in wood and brass 25.5 x 18.8 cm. Manufactured by Aston & Mander Ltd, London, 1912 with further numbering ‘IV’ and ‘4478’ plus the broad arrow. The obverse with fitted compass and the legends ‘Line of Direction’ and ‘To Clamp Roller’ and two graduated scales. The reverse with fitted brass crescent shaped graduated indicator. Provision for belt (?) mounting, good overall condition £300-500