As for me - its very nice for some DIY, just right now I'm making my first nixie thermometer based on this device and neon noise generators, maybe also will try with IN-13 nixie tubes. Case is very nice for base and mounting thermo-indicators. But of course thats for any of your own purpose, just telling my story with this device. Maybe could also use winding part as electric generator to make HV and supply neon tubes (with transformer of course). But at now thats just ideas.
Info from internet:
The MB-4M psychrometer is designed to determine relative humidity and air temperature.
The operation of psychrometers is based on the dependence of the temperature difference between dry and wet thermometers on the humidity of the surrounding air. The psychrometer consists of two identical mercury thermometers (GOST 112-78) mounted in a special frame and an aspiration head. The frame represents an oboe tube, bifurcating downward, and protective strips. Two pipes are attached to the lower bifurcated part of the tube using plastic bushings, which act as radiation protection for thermometer tanks. The upper end of the tube is connected to an aspirator. The aspiration head consists of a winding mechanism and a fan, closed by a cap. The spring of the winding mechanism of the MV-4M psychrometer is wound with a special key.
When the fan rotates, air is sucked into the device, which flows around the thermometer tanks, passes through the air pipe to the fan and is thrown out through the slots in the aspiration head. A dry-bulb thermometer will show air temperature, but a wet-bulb reading will be lower due to cooling caused by the evaporation of water from the surface of the cambric surrounding the thermometer reservoir. To determine humidity from dry and wet bulb readings, psychrometric tables are used.
Before work, the reservoir of the right thermometer is wrapped in cambric in one layer, and the edges of the cambric should only slightly overlap each other (no more than 1/4 of the circumference of the thermometer reservoir). After this, a piece of cambric prepared to size is moistened in distilled water and, while wet, tightly wrapped around the thermometer reservoir.
Having prepared two loops of thread, first tighten the cambric tightly at the top of the tank with one loop, and then, putting the second loop in the middle of the tank, gradually pull it all under the tank. while straightening the cambric. The thread under the reservoir should not be pulled too tight. Pulling the loop under the tank, it is tied. Having finished tying the cambric, the excess fabric is cut off directly under the thermometer reservoir.