26 Dr. Forry on the Climate of the United States, <^c. 



The climate of Fort Snelling, which is the most excessive 

 among all the military posts in the United States, resembles that 

 of Moscow in Russia, as regards the extremes of the seasons, not- 

 withstanding the latter is 11° farther north; but at Moscow the 

 mean temperature both of winter and summer is lower — that of 

 winter being as 10°'78 to 15°-95, and that of summer as 67°-10 

 to 72°-75. At Edinburgh, Scotland, in the same latitude as Mos- 

 cow, the difference between the mean temperature of winter and 

 summer, is, on the other hand, not one-third as great, being only 

 17°-90 ; and even at North Cape, on the island of Maggeroe, in 

 latitude 71°, which is the most northern point of Europe, this 

 difference between the two seasons, so great is the modifying 

 influence of the ocean, is no more than 19°-62, while at Uleo, in 

 the interior of Lapland, the difference between the mean tempe- 

 rature of summer and winter is 45°-90. 



In these comparisons of the Northern division, no particular 

 reference has yet been made to Fort Vancouver, in Oregon Ter- 

 ritory. This region bears the same climatic relation to our coast 

 and to that of Eastern Asia, as the western coast of Europe does. 

 The mean annual temperature is about 10° higher than that of 

 the posts on the same parallel on our own coast. So mild and 

 uniform are the seasons at Fort Vancouver, that the difference be- 

 tween the mean temperature of winter and summer is only 23° -67, 

 a mean which is less than that of Italy or southern France, and 

 only about two-fifths of that of Fort Snelling, Iowa, notwith- 

 standing the latter is nearly 1° farther south. This contrast is 

 well exhibited in Plate I ; for while the mean temperature of 

 spring, summer and autumn, at Fort Vancouver, is about the sam^e 

 as at Fort Wolcott, Rhode Island, the winter line comes nearly 

 as far south as Fort Gibson, Arkansas. But even this compari- 

 son, at first view, falls short of the reality ; for, as regards the dif- 

 ference between the mean temperature of winter and summer, 

 the contrast is less at Fort Vancouver l^an at Cantonment Clinch 

 near Pensacola, or Petite Coquille near New Orleans. These 

 results, however extraordinary they may appear, find, as will be 

 seen, an explanation in physical causes. 



The next point demanding attention is the difference between 

 the mean temperature of winter and spring, which is much the 

 greater in the excessive or rigorous climates. Taking places in 

 the same latitude and in opposite, systems of climate, it is found 



