189S-1902. No. 4.] DURATION OF PRECIPITATION. 



343 



with precipitation for the year (io, can be. found by dividing d by 4. 

 For the incomplete months, July to October, the mean value of d for 

 4 years may be computed in the following manner: 



Galling the number of liours with precipitation in one day of pre- 

 cipitation h, we have 



r, r N , ^ r N 



n = - -T, whence d = -^. 

 nd' nh 



Introducing, instead of the given shorter period of observations the 

 normal value Nq of the number of hours in each month, we have, for 

 4 years, 9 



AT ^^0 



* n h r N 

 nd 



^ N 



By employing these numbers, we get the following Table, in which 

 D is the number of days with precipitation, and H the hours of preci- 

 pitation in on day of precipitation, Comp. indicating computed, and Sm. 

 smoothed. 



