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2014/91/2 Hygrograph, S.N. R 17731, metal / glass / paper, made by Negretti and Zambra, London, England, 1950 -1960. Click to enlarge.

Negretti and Zambra hygrograph

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.


Object No.


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.


A plaque on the top reads, Negretti & Zambra, London. A plate inside the box reads: Hygrograph, MADE IN ENGLAND,
SERIAL No R/17731
RANGE 10/100%
REG No 698680



355 mm


265 mm


135 mm



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.



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.


Credit Line

Gift of Monica Daly, 2014

Acquisition Date

1 September 2014

Cite this Object


Negretti and Zambra hygrograph 2021, Museum of Applied Arts & Sciences, accessed 17 October 2021, <>


{{cite web |url= |title=Negretti and Zambra hygrograph |author=Museum of Applied Arts & Sciences |access-date=17 October 2021 |publisher=Museum of Applied Arts & Sciences, Australia}}