Interrogator for hygrometers of the VIT type, Zaporozhskaya oblast.

Product description.
The probe for hygrometers of the VIT type is intended for supplying water to a "wet" thermometer. The device is a glass tube bent at the end. Both ends of the tube are open. The tube is attached to the back of the hygrometer in such a way that the lower curved part is located under the "wet" thermometer. A fabric wick is inserted into the lower part of the tube, one end of the wick is lowered into the tube, and the other is wrapped around the reservoir with the thermometer's thermometer liquid. Then distilled water is poured into the tube, and it flows through the wick to the thermometer. Air humidity is determined by the temperature difference on "wet" and "dry" thermometers (according to psychrometric tables).(//tractor-service.com)

The questionnaire can also be used in the PBU household psychrometer.