Measuring air humidity.

This device is called psychrometer. You cannot do without it if you have an incubator. Of course, you can find it in specialized shops but you can make it yourself. You will need two thermometers for this. I fixed them in parallel on a small wooden board. Under one of them I placed a small pot for distilled water (a small trough for house birds will suit).

I wrapped the part of the thermometer where the mercury ball is, in thin cloth (cambric or gauze). I tied it up on top, but not very tight so as not to put obstacles in the way of water movement. Dip the lower edge of the cloth into the water approximately 5 mm deep, at this the cloth should not contact the pot walls.

The psychrometer should be installed in the incubator in such a way that thermometer reading should be seen when the incubator door is closed. The water will evaporate from the cloth surface and cool the mercury ball, this is why the wet thermometer will show the lower temperature.

We shall determine the relative humidity in the incubator with the help of the chart – it is given on the concurrence of lines of the dry and the wet thermometers readings.