• Vintage Mechanical Thermo-Hygrograph by Barruet Monnet (France) • Function: The device continuously measures and records both ambient temperature and relative humidity • Working principle: Temperature is measured with a bimetallic strip, and humidity with a bundle of degreased human hair • Data recording: Data is transmitted to the pins, which draw a graph on paper around a rotating drum • Mechanical key: Includes the original mechanical key on top used for winding and locking for safe transport • Application: Traditionally used in meteorology, agriculture, laboratories, and museums for long-term climate monitoring • Dimensions: Approximately 27 cm x 13 cm x 25.5 cm • Weight: 3000 g (3 kg) • Condition: Good vintage working condition. Note: there is a small internal crack/chip on the transparent acrylic cover (visible in photos, does not affect functionality)