4 PICTURE OF ORGANIZED NATURE. 



some change, in consequence of the different situations 

 of countries in the same degree of latitude : hence it 

 is, that countries in North Ameiica in the same lati- 

 tude are much colder than those in Europe; and 

 plants are found in Spitzbergen in 80 N. L. The 

 altitude of the snow-line is therefore drawn at a 

 mean ; the deviations from which are marked with a 

 star. 



The snow-line, when considered as to its position 

 to the Meridian, appears as a curve nearly resembling 

 an ellipse ; forming an eternal covering of snow ; 

 having its range, in every part of the globe, at a 

 certain unchangeable height, beyond which organic 

 life ceases. 



But besides this perpetual line of snow, there is 

 another, constantly varying according to the sea- 

 sons. In the Northern Hemisphere, after the Au- 

 tumnal Equinox, this line gradually becomes lower ; 

 being in the winter, according to circumstances, even 

 in the middle of the Temperate Zone, at the level of 

 the sea: on the contrary, in the Southern Hemi- 

 sphere, as the sun reaches the Southern Tropic, the 

 line rises, till it joins the perpetual snow ; and as the 

 sun returns towards the Northern Tropic, it again 

 gradually descends towards the sea. Thus organic 

 life fluctuates perpetually from North to South, and 



