PART I.] 



Average Characters of the Monthly Rainfall. 

 TABLE XXVII. 



?25 



CoTnparison of the Rainfall tvith the amount of Cholera in the months of Intermediate 



Prevalence. 



Here, on comparing June and October, there is diminished rainfall and diminished 

 prevalence ; on comparing October and November, diminished rainfall and greatly 

 increased prevalence ; and on comparing November, December and January, what is 

 practically unaltered rainfall with considerable decrease in prevalence. 



There are other conditions in reference to rainfall, however, which remain to 

 be considered. As yet the total fall per month alone has been dealt with, but it 

 is also necessary to inquire into the distribution of the fall, into questions relative 

 to the average number of rainy days in each month, the average fall on each of 

 these and the average of the heaviest falls occurring within 24 hours in each month. 



The following table, constructed on the data furnished by the observations at 

 the Surveyor GTeneral's Office, shows the average number of days on which rain fell 

 in each month of the past 21 years, together with the average per day of fall, and 

 the averages of the heaviest falls in 24 hours. 



TABLE XXVIII. 



Average Characters of the Rainfall of each month (21 years). 



These data regarding the characters of the rainfall in diflferent months fail to 

 show any correspondence between the phenomena of rainfall and prevalence beyond 

 that already indicated by the quantitative data alone. They show the same fact of 

 the coincidence of minimum prevalence with maximum rainfall, but with this all 

 indication of the existence of any definite relation between the two sets of phenomena 

 ceases to present itself. At one time — February and March — there is increase in the 

 average amount of individual falls with increased prevalence ; at aaothejc — rj^^ovember 



