Hygrometer - Metal - Hygrograph

Meteorological Hygrograph of the K.N.M.I. - 1950s
## **Auction Description:**
**Magnificent and historically unique vintage hygrograph from the absolute top manufacturer R. Fuess (Berlin-Steglitz). Executed in the iconic, glossy gray hammer-tone housing. This particular specimen is a rare piece of Dutch meteorological history: it originally came from the official inventory of the K.N.M.I. (Royal Netherlands Meteorological Institute).**
### **Operation & Mechanism**
A hygrograph (or hair hygrograph) continuously records relative humidity. This instrument uses the classical, highly precise scientific method with a vertical bundle of specially prepared human hairs (safely protected in the perforated metal tube). By the contraction and expansion of these hairs with changes in humidity, the long writing arm is mechanically driven.
In the drum there is a high-quality mechanical clockwork (type 'Werk 123 U-35') that is wound with the supplied original key. The clockwork is designed for a weekly registration cycle (1 revolution per 7 days).
### **Unique Provenance**
What makes this object truly special for collectors is the original metal nameplate at the handle with the inscription **K.N.M.I.** including the official inventory and calibration numbers (01 K.N.M.I. 07 / 004 - 07). This device actually stood in an official Dutch weather hut decades ago to accurately record the climatic data of our country.
### **Specifications and details:**
* **Manufacturer:** R. Fuess, Berlin-Steglitz (Germany)
* **Period:** Approximately 1950 - 1960
* **Serial number:** 85210
* **Drum type:** 221-a
* **Accessories:** Includes the original winding key and the fine writing mechanism with pen.
* **Condition:** In visually exceptionally beautiful, clean, and scratch-free condition. The hammer-tone lacquer shines superbly and the inner workings look very well cared for. The clockwork and mechanical transmission are present and the arm moves smoothly (operation with exact accuracy not tested, as is customary with this type of lots).
A splendid scientific precision instrument, a fantastic conversation piece and an absolute eye-catcher for lovers of industrial design, antique science and meteorology!