168 Mb. J. Bktce on the Recent Progress of the 



will do very well for January. To show how completely other causes 

 modify those depending on latitude merely, we may mention, as strik- 

 ing facts, that the isothermal of 23° F. in April passes from latitude 

 52° in Canada across Labrador, up to latitude 75° or 80° in Green- 

 land, bends E. to touch Spitzbergen in latitude 80°, and then descends 

 steeply to the mouth of the White Sea in latitude 68°. In January 

 we may pass from the Shetland Islands to the English Channel with- 

 out changing the temperature ; while, if we pass W. of this isothermal, 

 we have a higher temperatm-e, as in Cornwall and Ireland. The line of 

 32" r. passes from Philadelphia (latitude 40°) across Newfoundland, 

 touches the S. of Iceland, and reaches the polar circle (latitude 66^°) 

 on the meridian of Brussels ; it then descends perpendicularly, and 

 crosses central Europe to the Balkan mountains ; thence it runs due E. 

 to the east of China. These remarkable inflections point to the action 

 of other causes than the sun's declination merely, and on the west of 

 Europe are now universally ascribed to the Gulf Stream, that immense 

 body of tepid water which passes to the coasts of France, Britain, and 

 Norway, from the great heated and constantly overflowing caldron, 

 the Mexican Gulf. Other ocean currents, the varying floor of the 

 atmosphere, and the diffusion of vapour by the winds are also modify- 

 ing causes. Some exceptional phenomena ai"e yet waiting for explana- 

 tion. The existence of a " polar basin," that is, an unfrozen sea 

 about the pole, is strongly suspected. A party of Kane's expedition 

 remained for thirty hours on lofty cliffs on the west coast of Greenland, 

 in latitude 81^°, and looked down upon an open sea, with its waves 

 " trooping tumultuously from the pole " under a N.E. breeze, and yet 

 no drift ice was to be seen. Farther south the cold was the most fearful 

 ever encountered. The mercury froze at about — 68° F., and when sohd, 

 indicated by its contraction still lower, but undetermined degrees of 

 cold. What a grand object it would be to solve this great mystery, 

 and reach the pole upon an open summer sea from the N.W. point 

 of Greenland.* 



The researches of Dove have led him to abandon the old notion of 

 Brewster, Kaemtz, Mahlmann, and Berghaus, that two poles of maxi- 

 mum cold existed in the northern hemisphere. He does not recognize 

 their existence at all, and even goes so far as to say that " Brewster, by 

 confounding the polar with the equatorial map-projection, was led to 

 suppose that the isothermals of lowest temperature curved in separate 

 branches roimd two such poles of maximimi cold." In North America 



* Dr. Rink of Greenland, in a paper lately laid before the Royal Geographical Society, 

 endeavours to show that these observations of Kane's companions are not trustworthy, 

 and doubts the existence of such open water as they have described. — {April 24, 1858.) 



