ISOTHERM OF 0°. 141 



degree, touching Council-Bluffs (10°), on the 

 river Platte, Detroit (10°'l), in Michigan, 

 North Salem (10°'l), in New York, and then 

 runs a little to the south of Boston (9°*6) to the 

 Atlantic, from which, during its course to Europe, 

 it turns quickly up to the 51st degree N. L. 



The isotherm of 0° C. (32° Fahr.) follows the 

 north coast of Iceland and the Arctic Circle; it 

 touches the North Cape (0°'l), on the continent 

 of Europe, under latitude 71° N ; from this point 

 it turns suddenly to the south-west, running along 

 the chain of mountains that separate Sweden from 

 Norway (Alten 0°, Enontekis, in Russian Lap- 

 land, — 2 0, 7). It then, bending first towards the 

 south-east, returns to the Arctic Circle, touches 

 Tornea, leaves Uleaborg (0 o, 7), in Finland, on 

 the south, descends, towards the interior of Eussia, 

 (Petersburg 4°, Moscow 3°'9, Casan 2°'2), 

 more and more to the south, almost touching 

 Slatoust (0 o, 3), under the latitude of Moscow 

 and Casan. It then, leaving Ekaterineburg 

 (0°'5) andPetropablousk (1°'9) on its south, and 

 Tobolsk ( — 2 0, 4) far on its north, passes more 

 nearly parallel with the lines of latitude on the north 

 of Barnaul (1°*8), and near to Irkutsk (-0°'2), 

 then bends again towards the sea, cuts through the 

 middle of Kamschatka, and seems to reach again 

 to the Polar Circle on the north west of America. 

 In the interior of this continent, however, it again 



