This object is part of a collection relating to the history and development of calculating devices assembled by Assoc Professor Allan Bromley of Sydney University, comprising mathematical instruments, slide-rules, mechanical and electronic calculators, electronic analogue computers, computer components, kit computers, education computers, and associated ephemera.

Allan Bromley was a lecturer and researcher at the University of Sydney Basser Department of Computer Science from 1978 until his untimely death in August 2002. He specialised in Computer Architecture, Computer Logic and in particular the History of Computing. He was regarded as the world authority on Charles Babbage's Calculating Engines (instigating the building of the Difference Engine No.2 at the Science Museum London) and the Antikythera Mechanism and had extensive knowledge of calculators, analogue computers, logic, stereopsis, totalisators, clocks and time keeping and mechanical engineering.

Dollond of London, late 19th century

A Level or sighting device
Probably a Vertical Circle

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.

Made: 1875 - 1900

Inside lid of case, manufacturer's label: 'Hydrometer and mathematical instrument maker., 'Chart agent', '31 Poultry London'.

2010/1/40

1875 - 1900

110 mm

140 mm