Practical Exercises in Elementary Meteorology

by Robert DeCourcy Ward

Date.
Hour.
Pressure (in inches).
Temperature.	Dry Bulb.
	Wet Bulb.
	Max.
	Min.
Humidity.	Dew-Point.
	Relative Humidity.
Wind.	Direction.
	Velocity (miles per hr.).
	Total Miles per Day.
Clouds.	Kind.
	Amount (in tenths).
	Direction of Movement.
	Angular Altitude
Precipitation.	Time of Beginning and Ending.
	Kind.
	Amount.
Remarks.

A similar operation applied to the minimum temperatures gives the mean minimum temperature for the month.

In meteorological summaries it is customary also to include the absolute maximum and the absolute minimum temperatures, i.e., the highest and lowest single readings of the thermometer made during each month. These can easily be determined by simple inspection of your record book. Note also the dates on which the absolute maximum and the absolute minimum occurred.

The absolute monthly range of temperature is the difference, in degrees, between the absolute maximum and the absolute minimum.

Humidity.—The mean relative humidity is obtained by adding together all the different percentages of relative humidity obtained during the month, and dividing this sum by the whole number of observations of this weather element.

Wind.—The mean velocity of the wind corresponding to the different wind directions is readily obtained by adding together all the different velocities (in miles per hour) observed in winds from the different directions, and dividing these sums by the number of cases. The wind summaries will thus give the frequency of the different directions during each month, and the corresponding mean velocities.

The maximum hourly wind velocity is obtained by inspection of the velocity column.

The total monthly wind movement is readily deduced from the daily records in the twelfth column of the table on p. [44].

State of the Sky.—In connection with the more advanced records described in this chapter, the observations of cloudiness should record the number of tenths of the sky cloudy, as closely as the amount can be estimated by eye, instead of indicating the state of the sky as cloudy, fair, etc. A detailed record of