INRAIN AND SNOW, IN THE UNITED STATES. 



207 



The following table gives the monthly per centage of the mean annual rain-fall 

 obtained by dividing, in each series, the amount in each month by that of the 

 year, and shifting the decimal point. 



Monthly Per Centage of Rain- Fall. 



Month. 



i") 



(*) 



(0 



Mean of 





1738-59 



1841-61 



1842-59 



d and c. 



January- 



4.q 



5-9 



5-7 



^.8 



February 



6.S 



S-S 



S-5 



5-5 



March 



6.,^ 



9.0 



9.2 



9.1 



April 



4.0 



4.0 



3.8 



3-9 



May 



7-4 



8-5 



8.4 



8.S 



June 



10.5 



8.7 



9-5 



9.1 



July 



13-5 



13.8 



14. 1 



13-9 



August 



iS-9 



16.4 



16.8 



16.6 



September 



12.4 



II. 2 



10.8 



II. 



October 



6.0 



6.^ 



4-7 



5-5 



November 



4.8 



4.2 



4.6 



4.4 



December 



6.9 



6-5 



6.9 



6.7 



The numbers of columns (a), (h), and (c) are plotted on the accompanying 

 gram 4, the first by a full line, the second by dashes, and the third by dots, 

 accordance of these lines is sufficiently close to indicate no material change. 



Diagram 4. 

 J. F. M. A. M. J. J. A. S. O. N. D. J. 



dia- 

 The 



In the following tables the monthly percentage of the annual rain-faU is given 

 for successive periods for two of the longest series available, and for a third station 

 selected on account of its geographical position. 



18 July, 1871. 



