SERIES III: RELIQUARIES for OBJECTS THAT MEASURE
Antique Horsehair Hygrometer
Hygrometer, wood sheet and trim, cloth, brass repousse, antique print
24 1/2" ht. x 18 3/4" w. x 3 1/4" d.
A horsehair hygrometer is an analog instrument that measures relative humidity by utilizing the natural tendency of hair to expand and contract based on moisture in the air. As humidity rises, the horsehair absorbs moisture and lengthens; as the air dries, it shrinks. The mechanical stretch is amplified by the levers and moves the needle across the dial to give a humidity percentage reading. (Whipple Museum)
The antique print references historical hygrometer examples. I love antique scientific engravings and etchings as well.