Europe : — a popular Physical Sketch. 405 



from the interior of which flows lava (' Hraun') which with 

 ashes, stones, water, sand, and clay, thrown out through the 

 craters, frequently cover extensive districts. Of useful mi- 

 neral productions, are found sulphur (the most extensive 

 mines at Husabig and Krisuvig,) and ' Surtarbrand,' i. e., flat 

 pressed, carbonized trunks of trees found among the strata. 



Considering the locality, Iceland enjoys a mild climate, 

 and particularly mild winters. 



Annual. Winter. Summer. 

 Reykiavig, ... 64° north lat. 39.8 29.8 55.6 



Eyafiord, ... 66° 32 20.8 45.5 



The mean temperature of Reykiavig is consequently equal 

 to that of Norway of equal latitude, and 4.5° higher than 

 that of Umea. 



The winter is 6.8° milder than at Drontheim, and 15.7° 

 milder than in Umea, but then the winter is of much longer 

 duration, for during five months (November to March) the 

 mean temperature is below freezing point. The mean tem- 

 perature of the summer in Reykiavig is 3.3° lower than 

 at Drontheim, and not quite so high as in Umea. 



The climate of Reykiavig is still milder compared to that 

 of North America, particularly the interior part ; for at Nain 

 in Labrador, situated 7° more southerly, the annual mean 

 temperature is 7.8° below the freezing point, and the win- 

 ter 32.6° below the same. In Fort Enterprize, at the latitude 

 of Reykiavig, in which Capt. Franklin wintered, the annual 

 mean temperature, from probable calculation, appears to be 

 20° below the freezing point, and that of the winter — 55.5° 

 below zero. 



But the results found at Eyafiord tend to prove that there 

 is a great difference between the southern and northern part 

 of Iceland, much more so than might reasonably be expected 

 from difference of latitude. 



At Eyafiord the mean temperature is 32°, about equal to 

 that of the North Cape, notwithstanding Eyafiord is situated 



