|| | ALTITUDE | || |+--------------------------------------+----------------+---------------+| || | TIME OF | || || | BEGINNING | || || | AND ENDING. | || |+--------------------------------------+----------------+ || || | KIND. | PRECIPITATION.|| |+--------------------------------------+----------------+ || || | 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.