224 Dr. Forry oti the Climate of the United States, S^c. 



These results, comprising some of the posts in the Northern 

 division of the United States, are exhibited in the following 

 table : 



It is thus seen that in excessive climates the law above stated 

 holds good invariably. There is but one exception in the tables 

 appended to the author's work before alluded to, viz. Fort Craw- 

 ford, 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' observa- 

 tions ; the mean of April being 2°'50 lower, and that of October 

 2°"54 higher, than the annual mean. Fort Yancouver, which is 

 not situated near a large body of water, derives its uniform cli- 

 mate from its position near the western coast of the continent. 



A decision of this long mooted question is thus presented, illus- 

 trating the ancient axiom, that truth is never found in extremes. 

 Kirwan, however, was somewhat nearer the truth than Hum- 

 boldt. As regards any credit that may pertain to this explana- 



