Negretti and Zambra hygrograph
Object No. 2014/91/2
A hygrograph measures and produces a graphic record of the relative humidity of the air in a building. Human hair is used as a component because it changes length as it absorbs water vapour. Relative humidity is measured by this change. Because raw wool is covered in flammable lanolin, it was extremely important to maintain a constant humidity in Sydney's wool stores which were large brick and timber structures. Hygrographs were essential monitoring equipment used in the wool stores. Negretti & Zambra were reputed to be the world's finest instrument makers of their time. They specialised in making metrological instruments. Sandra McEwen Principal curator, biosciences August 2014
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Summary
Object Statement
Hygrograph, S.N. R 17731, metal / glass / paper, made by Negretti and Zambra, London, England, 1950 -1960
Physical Description
The machine consists of a glass and metal box that encases a cylinder around which a paper chart is wrapped. A pen on an arm sits against the chart. A small 'chimney' is mounted on one side of the box.
DIMENSIONS
Height
355 mm
Width
265 mm
Depth
135 mm
PRODUCTION
Notes
The hygrograph was manufactured in London by Negretti & Zambra, scientific instrument makers to Her Majesty Queen Victoria, Prince Albert and Edward VII of the United Kingdom, the Royal Observatory and the British Admiralty. The firm was founded in 1850 by Enrico Negretti and Joseph Zambra and produced quality instruments for the next century.
HISTORY
Notes
All that is known of this hygrometer is that it was used in a wool store situated on the Alexandria Canal in the suburb of Alexandria, Sydney, New South Wales before 1950. It was rescued from the building before the building was demolished to make way for apartments in the 1950s.
SOURCE
Credit Line
Gift of Monica Daly, 2014
Acquisition Date
1 September 2014
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