Optical Square Rangefinder c.1905 R. H. Stocken Soon afterwards he was assigned

Soon afterwards he was assigned to military service in Egypt

thanks largely to their Canadian instructors

aluminium dial with black painted centre and luminous paper markers

and allied air forces

Optical Square Rangefinder c.1905 R. H. Stocken Soon afterwards he was assignedAn Optical Square rangefinder, dating from c. 1905, complete with its original fitted leather case. Reputed to have been invented by George Adams Senior in the middle of the 18th century, the optical square appeared in the 1795 catalogue of George Adams Junior as 'A small instrument for surveying by right angles'. In the 1907 Negretti & Zambra catalogue it was described as being used 'for fixing a right angle, and in the laying off of offsets'. A