POLES OF LOWEST TEMPERATURE. 407 



for appreciating the nature of tlie evidence Ly whicli CHAFTEn 

 such results are established. Elevated plateaus, moun- * _^ ' 

 tain ranges rising within the region of perpetual snow. Causes of 

 vicinity to, or distance from the ocean, insular or inland 

 position, extensive natural irrigation, geological peculiari- 

 ties of soil and stratification, and the peculiar develop- 

 ment of vegetable life, all more or less influence the 

 temperature of regions, establishing temperate climes 

 alike within the torrid and the frigid zones, and filling the 

 ample beds of the Nile and the Euphrates, from the 

 snows that melt within the range of the equatorial sun. 

 It is now well known that the magnetic pole does not 

 coincide with the true geographical pole. The results of 

 Humboldt's isothermal system, as deduced from his own 

 personal investigation, has led to extended observations by 

 others, which also promise to be productive of the most 

 important results. One of these aims at establishing the Position of 

 actual position of the cold poles, or the precise points in lo^velt" 

 the northern and southern hemispheres, where the mean temperature, 

 temperature is lower than at any other part of the globe. 

 Already an approximation to this has been made, an<l 

 though it is still unsafe to attempt to deduce any abso- 

 lute or precise conclusions from this, it is remarkable that 

 the eastern and western poles of lowest mean tempera- 

 ture, appear very nearly to coincide with the magnetic 

 poles of the earth. This remarkable result is well calcu- 

 lated to excite the liveliest interest in men of science, and 

 to urge them to renewed zeal. It may, indeed, prove 

 that the connection of the cold and magnetic poles is 

 merely accidental, but meanwhile it seems more probable 

 that it points to some important, and hitherto imknown 

 law, which shall yet reveal the full nature and extent 

 of operation of that mysterious power which is known as 

 magnetism. 



A glance at the map of the two hemispheres, accompa- Variations 

 nied with some knowledge of the ascertamed isothermal temperaturs 

 data, is sufficient to show how great are the variations of 

 mean temperature that may be looked for. The geogra- 



