On the Physical Geography of Norway. 297 



parallels of latitude. But as the continents are hotter than 

 the ocean between the tropics, and colder in higher latitudes, 

 the lines of temperature have a descending loop over the 

 Atlantic and Pacific Oceans in the former circumstance, and 

 an ascending one in the latter.* Thus, for example, the iso- 

 thermal line of 40° Fahr., which passes nearly over Thrond- 

 hjem in Norway (lat. 63°), and attains perhaps the 66th de- 

 gree of latitude over the Atlantic, falls to the 48th degree 

 in Canada (a little north of Quebec), and to the 50th or lower 

 in the eastern parts of Asia, but rises again under the influ- 

 ence of the Pacific Ocean to about 60° of latitude on the west- 

 ern coast of North America. 



A farther step in these important and curious generaliza- 

 tions (which are due primarily to Von Humboldt) consists 

 in distinguishing the summer and the winter curves of tem- 

 perature, which have an important bearing on the existence 

 of perpetual snow and glaciers. Places with the same aver- 

 age temperature may be yet, the one temperate and whole- 

 some, the other nearly uninhabitable from extreme cold dur- 

 ing winter, which is compensated by the almost tropical heat 

 of the summer months. Thus whilst at Throndhjem the dif- 

 ference of temperature of January and July is 40° Fahr., at 

 Jakutzk, in Siberia, which is nearly on the same latitude, 

 this difference amounts to 114°; and mercury is sometinies 

 frozen for three months of the year. In the Faroe Islands, 

 on the other hand, the climate of which is perfectly insular, 

 the variation between January and July is only about 18°. 



Whilst then, Norway enjoys the average climate superior 

 to any other continental country in the same latitude, it is 

 also, on the whole, less visited by extremes of summer heat 

 and winter cold. No doubt, the different portions of the 

 country vary distinctly in this respect, the coast possessing 

 the moderate or insular character, the interior or Swedish 

 side a much severer one ; still, on the whole, the statement is 

 true. It is vividly represented by the isothermal lines for 

 January and for July, drawn by Professor Dove of Berlin, and 



* See the map of Isothermal lines in Berghaus' and Johnston's Physical Atlas. 

 or in the neat and cheap maps published by the National Society. 



