142 



TABLES AND RESULTS OF THE PRECIPITATION, 



Locality. 



Aggregate 

 years. 



Days. 



Locality. 



Aggregate 

 years. 



Days. 



New Hampshire .... 

 Massachusetts & Connecticut 



Delaware, Maryland, and 

 District of Columbia . . 



North and South Carolina . 

 Mississippi and Louisiana . 



89 



is 

 26 

 26 



50 



214 



12 



93 



58 

 37 

 5 2 

 18 



77 



17 



5° 



■ in 



is 



93 



76 



89 



98 



96 



109 



118 



119 



83 



85 

 89 



83 

 9 1 

 98 

 92 

 58 

 75 



Ohio 



Indiana and Illinois . 



Indian Territory .... 

 Washington Territory 3 . . 



10 

 Il8 



87 

 IO 



48 



47 

 19 

 49 

 60 



43 



10 



8 



47 

 8 



47 

 16 



*9 



14 



89 



116 



117 



I07 



89 



89 



98 



70 



73 



77 

 75 

 72 



56 



75 



5o 



131 



132 



235 



At Toronto, Canada, the number of rainy and snowy days averages 162 in a 

 year, as derived from 23 years of record; at Hamilton, Canada, ten years of record 

 gave 122 days. 



For Colorado, Dakota, and Utah, from three, four, and one year of record, we 

 have 51, 72, and 102 days of precipitation, respectively. 



From the above table, and by means of the ratios of amount for each month, 

 compared with the mean amount, we can readily deduce the probable number of 

 rainy days in any given month ; thus, for the month of May, in the State of New 



York, for instance, we have the average number of rainy days in a month = 



109 

 12 



by preceding table, and the monthly ratio 1.14 from Table, Type II, hence, number 

 of rainy days to be expected in May = 1.14 times zzf.= 10. 



The aggregate number of years upon which the average numbers for rainy and 

 snowy days of the preceding table depend is 1620. 



SECULAR CHANGE OF THE RAIN-FALL. 



The question whether the annual rain-fall is gradually increasing or diminishing, 

 stationary, of a periodic character, or apparently irregular, is one of great interest, 

 scientifically as well as practically. The preceding table B has been specially pre- 

 pared for the investigation of these changes of the annual amount of rain, and if 

 these records should not be of sufficient extent, they will at least form a basis for 



1 Average very uncertain, the precipitation depending too much upon the elevation and other 

 circumstances. Number of rainy and snowy days vary between 31 and 93. 



2 The extremes, Fort Yuma 11 days, and Fort Humboldt 82 days, also Fort Crook 83 days, are 

 not included in the tabular mean. Average hardly admissible without further specification, as in the 

 case of New Mexico. 



3 Averages uncertain without specification. 



