Humidity

—The watery vapor always present in the atmosphere; it varies with the temperature, being greater during warm weather. The degree of saturation, or relative humidity of the air, is determined by the use of the wet and dry bulb thermometers. The feeling of wetne or dampne in the air does not depend mainly on the absolute amount of vapor present, but chiefly on the nearne of that vapor to its saturation point Thus, on a warm day in summer, there is probably much more vapor present than on a damp winter day. | In the latter case, the temperature of the air is very little above the dew point; that is, the air is nearly saturated and a very small fall of temperature will cause the vapor to be deposited as moisture. On the summer day, a greater fall is needed before the dew point is reached and the air begins to feel damp.