NO. 17.] 



PRECIPITATION. 



529 



The most frequent winds with precipitation are southerly to south-easterly, 

 in July and August south-westerly. The westerly winds are much less 

 frequently attended with precipitation, and calms very seldom. 



Taking the number of cases in which precipitation has been observed 

 with a certain wind in a month, and dividing this number with the number 

 of cases in which this wind has been observed in the same space of time, 

 we get a number which gives an expression for the probability of precipi- 

 tation with that wind. The following Table shows the result of such a 

 computation. 



67 



