S30 M. Humboldt oji the Difference (>fthe 



relative position of the transparent and opaque, of the fluid or 

 solid parts of the earth, modifies the absorption of the solar rays 

 falling under the same angles, and at the same time the produc- 

 tion of heat. These circumstances, the winter cover of ice and 

 snow, which is peculiar to the continents, and to a very small 

 part only of the seas ; the slowness with which large masses of wa- 

 ter are heated and cooled ; the radiation from smooth or rough 

 surfaces, towards a cloudless sky ; the regular currents of the 

 ocean and of the atmosphere, by which water and air from dif- 

 ferent latitudes and different depths and heights are mixed ; all 

 concur to produce the peculiarities of climate. It may therefore 

 be said, that every place has a double climate, one depending on 

 general and remote causes, on the general position and shape of 

 the continents, and another determined by the peculiar relations 

 of its locality. 



Since the problem of the geographical distribution of heat has 

 been considered upon general principles, meteorological ob- 

 servations have been conducted in a more efficient manner. 

 A smaller number of them now lead to certain results ; and 

 ibe discoveries made within the last twenty years, in the most 

 remote parts of the globe, have gradually enlarged the point 

 of view. Physical and geological inquiries have now become 

 equally important objects of all extensive voyages and tra- 

 vels. To begin with the extreme north, I shall here, in the 

 first place, mention a man, whom the dangerous and trouble- 

 some occupations of whale-fishing, which were the object of his 

 voyage, have not prevented from carrying on the most refined 

 meteorological and zoological observations. Captain Scoresby 

 has, for the first time, determined the mean atmospheric tem- 

 perature of the Polar Seas, which he has taken between the 

 volcanic Island of Jan Mayen, and that part of East Greenland 

 discovered by himself. In endeavouring to discover a north- 

 west passage, the English government has succeeded in affording 

 to geography, to climatology, and to the theory of magnetism, 

 services which were originally promised to the commercial inte- 

 rest of nations. Parry, Sabine, and Franklin have, for several 

 years, been employed in investigating the temperature of the at- 

 mosphere, and of the sea, in the polar regions ; they have pene- 

 rated to Port Bowen and Melville's Island, consequently nearly to 



