THE POLAR GLACIERS. 23 



desolate and ice-bound regions. The zone of the antarctic lias 

 been encroached upon only in a small space south of the Pacific. 

 On every other side, so far as has been discovered, mountains of 

 ice block the way on and near the polar circle, which seems to be 

 the great ice-barrier of the south pole. Discoverers suppose 

 what they have looked upon to be land, but rarely have they 

 ever seen anything but rolling ranges of ice and snow rising 

 higher and higher as far as the eye could reach. In the most 

 open of the south-polar seas, Sir James Ross, in 1841, sailed 450 

 miles along an unbroken cliff of ice from 150 to 250 feet high, 

 and of unknown depth beneath the water. It was one of the 

 vast antarctic glaciers pushing down into the sea, from which 

 some of those southern icebergs were broken off, that navigators 

 have frequently laid down for islands, while the next sailor that 

 voyaged that way found open water where they were charted. 



Not a sign of vegetation, not an indication of thawing, has 

 ever been discovered within or near the antarctic circle, whereas 

 there are aboriginal races and numerous settlements of civilized 

 communities on every side within the arctic circle. The whale- 

 boat or the dog-sledge has traversed the arctics and found the 

 sea-level in almost every degree of high latitude. In the south 

 no adventurer has yet penetrated within probably 1,500 miles of 

 the center of greatest cold. Whence comes this great differ- 

 ence in the climate and ice accumulations of the two poles of 

 the earth ? It is the object of this article to inquire if, in the 

 astronomical relations of our planet, there are found any sufficient 

 causes for such differences. 



The path of the earth about the sun once every year is an 

 ellipse, with the sun in one of the foci or centers. An ellipse is 

 a circular figure having two centers instead of one ; that is, the 

 circumference is everywhere equally distant from the two centers 

 taken together- the sum of the two distances is always the same. 

 Therefore, the sun being in one of these centers, the earth is 

 nearer to it in one half of the year than in the other. At the 

 present time the nearest approach, or the perigee, occurs about 

 the 1st day of January ; and the earth is at that time 3,200,000 

 miles nearer to the sun than it is on the 1st day of July. 



