Vertical circle, sighting device with case, metal / glass / wood, made by Dollond of London, London, England, late 19th century
This object, when assembled sits on a base with three adjustable feet. The top array has a spirit level and a calculating dial. The object folds into its wooden case.
A vertical circle is an instrument used to measure the decliination of a celestial body, or in geodesy to measure the altitude of a mountain or hill. It is similar in fuction to a clinometer.
Inside lid of case, manufacturer's label: 'Hydrometer and mathematical instrument maker., 'Chart agent', '31 Poultry London'.