Vintage Negretti And Zambra Relative Humidity Meter. Wall Hanging

This is a very nice, small (4 1/4 inch diameter), Vintage Negretti And Zambra Relative Humidity Meter in a black cast casing with a hook for wall hanging. 

In pretty good working condition, with a few surface scuffs and scratches in the paintwork, and a few flecks of dirt under the glass, commensurate with age and use. I am not sure how accurate it is at measuring % Relative Humidity, and I haven't tried to calibrate it.

Approximate Face Diameter: 11cm
Approximate Rear Diameter: 9.8cm

A hair hygrograph measures the humidity (or dew point). It works by using the principle that a human or horse hair changes length depending on the level of humidity in the air. This particular instrument was manufactured, approximately, in the 1950s but the design dates back much earlier. They were also sold as pocket instruments, although you'd need fairly big pockets or a lab coat!

The face is marked as follows:-

Range 0/ 100%
Negretti and Zambra Logo
Percentage Relative Humidity
Made in England
Negretti & Zambra
London

All in all this represents a scarce opportunity to obtain one of these instruments for use or to add to your collection.

Please click on the following link for more vintage weather/meterological instruments

Some Trivia For You

Negretti & Zambra was founded in 1850 by Henry Negretti and Joseph Zambra. The company has a world renown reputation for producing some of the finest quality scientific, meteorological, and optical instrumentation. In fact, so good that they were appointed instrument makers for the Royal Observatory, British Admiralty and members of the British Royal Family; including Queen Victoria.

Negretti was acquired by Meggitt Holdings in 1985.
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