CALORIC. 443 



continent, as borne by the prevalent winds, by the wall of 

 mountains. 



Lorin Blodget describes the climate approaching the west- 

 ern side, and far interior of the continent, as " singularly 

 mild and warm," compared with the range of the eastern 

 coast. " On the Tipper Missouri an extensive region was 

 as mild in climate as St. Pauls in Minnesota." Wheat grows 

 on Mackenzie's River nearly to the sixty-fifth parallel. 



"The comparison of climates for the United States shows a rapid 

 increase of heat in going westward, on any line of latitude from 

 points in Minnesota, and this even when the elevation increases. It 

 is warmer at Fort Benton on the Missouri, in longitude 110^ west, 

 and latitude 472 during every season, than at St. Pauls, Minnesota. 

 The isothermal lines, even for winter, curve very largely northward 

 over this space, indeed they curve most for this season, making there 

 more difference in the temperature than in any other part of the 

 year. At Sitka, on the Pacific coast, in Kussian America, at 57 

 north, the winter temperature is 33-^, which is as warm as at St. 

 Louis, Washington City, and Philadelphia. Beginning at the coldest 

 side of the continent, we have not yet ascertained the value of the 

 west side. If the mountains were removed, the whole area would cor- 

 respond in climate to the west of Europe, very nearly at least; at 

 the latitude of St. Petersburg it would be as habitable as that part 

 of Russia is," etc. etc. 



From all of which statements of Mr. Blodget it appears 

 that the isothermals on the east side of the continent make 

 a most singular and rapid declension southward. 



On the subject of the causes of fluctuations of tempera- 

 ture on the eastern side of the continent, Mr. Butler has the 

 following suggestions as to the magnetic causes of the same 

 phenomena : 



"To the difference in the magnetic intensity of the eastern portion 

 of this continent, compared with Europe and our western coast, 

 very much of the difference of climate, so far as temperature is in- 

 volved, may be attributed. We have seen in what manner the 

 isothermal lines surround these areas of intensity. So the most 

 excessive climate, that is, the climate where the greatest extremes 

 alternate, other things being equal, is upon, or near, the line of area 

 of greatest magnetic intensity. I say other things being equal, be- 



