34 



information: Each diagram represents a month's time and is di- 

 vided into 30 or 31 equal sectors in accordance with the number of 

 days. The outer margin gives the wind direction averaged for each 

 12-hour period and also the force in terms of Beaufort scale. The 

 next adjacent ring contains information on the amount of fog and 



Fig. 2. — April weather diagram 



low visibility experienced during the month; the fog is filled in full 

 black and the low visibihty in crosshatched shading. The third 

 band in contains a continuous barograph record for the entire month 

 and is drawn to scale. The numerals on the innermost ring signify 

 the days of the month. 



