44 Dr. Forry on the Climate of the United States, fy 





In the United States, if the comparison is confined to the same 



system of climates, as for example the posts on the ocean or 



lakes, or those remote from the agency of large bodies of water, 



the limits of variation, as in Europe, are also narrow ; but if the 



whole extent of our domain is embraced, the results are strikingly 

 diverse. Thus 



Fort Vancouver, Oregon Territory, 



Council Bluffs, junction of Platte and Missouri, 



Difference, 



MEAN TEMPERATURE. 



Annual. 



f Winter. 



{Summer. 



51°-75 

 51°02 



41°-33 



2 4 o. 47 



4-16° 86 



65° -00 



75° -82 



- 10°-82 



0°73 



Here, then, although there is not a degree of difference in the 

 mean annual temperature of Fort Vancouver and Council Bluffs, 

 yet the mean winter temperature of the latter is nearly seventeen 

 degrees lower, while the mean summer temperature is nearly 

 eleven degrees higher. But this contrast is exhibited in a still 



more marked degree by comparing the difference between the 

 mean temperature of winter and summer, the former being 23°-67, 

 while the latter is 51°-35. 



" In tracing five isothermal lines between the parallel of Rome 

 and St. Petersburg," continues Humboldt, " the coldest winter 

 presented by one of these lines is not found again on the preced- 

 ing line. In this part of the globe, those places whose annual 

 temperature is 54°-50 have not a winter below 32°, which is 

 already felt upon the isothermal line of 50°." 



In the European climate, two points having the same winter 

 temperature may differ as much as 11° in latitude. Thus in 

 Scotland, in latitude 57°, and isothermal line 45°50, the winters 

 are more mild than at Milan, in latitude 45° 28', and isothermal 

 line 55°-S0. Consequently the lines of equal winter cut isother- 

 mal lines which differ 10°. At the isle of Maggeroe, at the 

 northern extremity of Europe, under the parallel of 71°, the 

 winters are 7° milder than at St. Petersburg, latitude 59° 56'. 

 In the United States, embracing the whole region between the 

 Atlantic and the Pacific, as great a contrast no doubt exists. 

 The mean winter temperature of Fort Vancouver, Oregon Ter- 

 ritory, latitude 450 37', is found about 9° farther south at a point 

 intermediate to Fort Gibson and Jefferson Barracks ; but if the 

 observations, like those in Scotland just referred to, were made 

 on the coast, (Fort Vancouver being 70 miles distant from the 

 lacific,) the winter temperature would necessarily be still higher. 



