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 Ankithera Mechanism and had extensive knowledge of calculators, analogue computers, logic, stereopsis, totalisators, clocks and time keeping and mechanical engineering.

Casella, London
for Air Ministry Meteorological office, UK.

Optical calibration device with case and cleaning cloth, neutral density contrast gauge, Bakelite / glass / rubber / cotton, made by Casella London for Air Ministry Meteorological Office, England, c.1940s

Neutral density contrast gauge
A test instrument with a graded neutral density filter mounted in a slide out support with grade markings on the side. The eyepiece has blocked and open sections. Made in black Bakelite in purpose built wooden box.

Mfr: Casella, London (makers of meteorological and photogrammetry and dust measuring instruments)

Has Air Ministry, Meteorological Office ticket marked "For Use in Test Laboratory", dated 27 Nov 1946.

Made: 1935 - 1945

Hold in Left Hand
Casella, London
MK II . M 1789/44

2010/1/184

1935 - 1945