Antique Henry J Green Model 1164 Hair Hydrometer Antique Scientific Instrument

Description

FOR SALE
Hygrometers
Hygrometers are weather forecasting devices that measure humidity levels in the air. Changes in humidity, in turn, indicate the likelihood of pending dry weather or precipitation. Hair hygrometers like the one shown below, used horse hairs to measure and (sometimes) record air humidity.
This clever design works because hair relaxes and lengthens when humidity in the air increases, and contracts when the humidity decreases. Because of this predictable response to humidity changes, hair can be used to alternately pull and release a lever in response to humid and dry conditions. This device essentially records changes in the length of horse hairs as a proxy for changes in humidity.
The movements are then tracked by a nib which traces an ink along paper on a rotating drum. The drum is rotated once a week by an eight-day Clockwork. The hygrometer shown here is over 50 years old and continues to track ongoing changes in humidity on a week -long chart.
This hygrometer was made sometime after 1890. We know this because the company name shown in the image was only used after 1885 when Henry J Green took the company over from his Uncle, instrument maker James Green. HJ Green then moved from New York to Brooklyn in 1890.  Although the measurements are not as precise as could be achieved with other contemporary weather prediction devices, and the accuracy is particularly limited in conditions of extremely high or low humidity, hygrometers reduced the need for mercury based technologies, and provided sufficient information for their typical uses at the time.
This is a very rear model, I dont know on how to test it out so will be selling it for part
Enjoy