NO. 17.] 



PRECIPITATION. 



533 



In 1895, the rainy season was rather late. 



Hail was observed only 5 times, viz. in 1894, June 10 and July 11, 

 in 1895, July 6 and 7, and in 1896, March 27. 



Counting the number of cases in which the precipitation has lasted one 

 day, two days, etc. (of course with interruptions during the 24 hours), and 

 taking the means for one month, we get the numbers in the following Table. 



NUMBER OF PERIODS LASTING 



We have the months October to July for 3 years, and August and September for 2 

 years. Thus, e. g. I'O signifies for March 3 cases in 3 years, 0"3 one case in 3 years, 

 1'5 for August, 3 cases in 2 years, etc. 



The most frequent period is that of one day. The frequency of the 



periods decreases with the length of the period. The frequency of the 16 



days' period is rather remarkable, but the number of years is too small to 



give more exact statistics. 



The following Table has been computed by Koppen's Method.^ 



For a certain period, e. g. a month, let 



n be the total number of observations made 



r - - - — • — of precipitation 



N - - - — - hours in the period (month) 



d - - number of days with precipitation (rain or snow). 



1 Oesterreichische Zeitschrifl ftir Meteorologie f. 1880 p. 362 and Meteorologische Zeit- 

 schrift f. 1885 p. 10. 



