What is dew point temperature, dry bulb temperature and wet bulb temperature of the atmospheric air?
It is as Irv S says. However, here is a bit more information: The wet and dry bulb thermometer has been used for at least a century on ships to predict the fog. The wet & dry bulb thermometers were installed outside of the bridge, in a place open to the wind but protected from direct sunlight. The wet bulb was kept constantly wet with water on cotton wool. Both wet and dry temperatures were plotted and also the sea water temperature taken in a bucket. If a projection in time would show that the curves were to meet, i.e. the average of both bulbs equal the sea temperature, it was the time fog would appear; something that was usual on coastal navigation in places of strong tidal streams. Meteorologists on land, as at airfields, would swing the thermometers in a slinge in order to create wind and evaporate the water to measure the wet bulb temperature. Dew point temperature is the temperature at which the air is so saturated with water (relative humidity = 100 percent) that it has to cond
