216 Dr Forry on the Climate of the United States. 



its mean temperature is augmented by a sudden vernal m- 

 crease. These results, comprising some of the posts in the 

 Northern Division of the United States, are exhibited in the 

 followina; table : — 



It is thus seen that in excessive climates the law above 

 stated holds good invariably. There is but one exception in 

 thetables appendedto the author's work before alluded to, viz., 

 Fort-Crawford ; but the results of this post are based on only 

 two years' observations. Fort-Howard, it is seen, has, in 

 April, a somewhat lower mean than that of the year, which, 

 as it differs from the rest in this respect, in consequence of 

 having its temperature partially modified by the waters of 

 Green Bay, is an exception which confirms the rule. At the 

 posts in the modified climates, the mean temperature of April, 

 with the single exception of Fort- Sullivan, is generally as 

 much lower as that of October is higher than the annual mean. 

 This law is beautifully illustrated in the results obtained at 

 Salem, based on thirty-three years' observations ; the mean 

 of Api'il being 2^ 50' lower, and that of October being 2° 54' 

 higher than the annual mean. Fort-Vancouver, which is not 



