274 NOTES OF A NHTURALLST. 



at the mouth of the St. Lawrence, lat. 49 '^ 24' north, 

 the main yearly temperature is only 3 5 "8°, or more 

 than 7° below that of the Falkland Islands. But it 

 may be truly said that, although the stations now 

 under discussion are on the eastern side of the South 

 American continent, they virtually enjoy an insular 

 climate, and that there is probably little difference 

 between their temperature and that of places on the 

 west side of the Straits of Magellan. 



On comparing the few places out of Europe from 

 which we possess observations in high northern 

 latitudes, I think that the station which admits of 

 the fairest comparison is that of Unalaschka in the 

 North Pacific. The observations at Illiluk in that 

 island, in lat. 53"^ 53' north, show a mean annual 

 temperature of only 2)^'2° Fahr., while at Ushuaja, 1° 

 farther from the equator, the mean temperature is 

 higher by more that 4°. It is true that at Sitka, in 

 lat. 57° north, we find a mean temperature of 43*28° 

 Fahr., or about the same as that of the Falklands. 

 But the position of Sitka is quite exceptional. It is 

 completely removed from the influence of the cold 

 currents that descend through Behring's Straits, and 

 a great- mountain range protects it from northerly 

 winds ; south-westerly winds prevail throughout the 

 year, and a very heavy rainfall, averaging annually 

 eighty-one inches, imports to the air a large portion of 

 heat derived from equatorial regions. On the coast 

 of Western Patagonia and Southern Chili, this source 

 of heat is partly counteracted by the cold antarctic 

 current that sets along the western coast of South 

 America. 



