638 POPULAR SCIENCE MONTHLY. 



under the masses of ice we discover remains of plants that 

 demonstrate the presence not so very long ago of a nourishing 

 tropical or subtropical vegetation instead of the present ice. We 

 meet mountains of ice everywhere, and everywhere the arctic 

 region is sublime. Man's disposition to make all the earth his 

 home and himself at home everywhere in it is only sharpened by 

 the problems offered there, and the tendency to go becomes 

 irresistible. 



There is thus much to observe and much to learn in these 

 regions for the satisfaction of our irresistible longings. First, we 

 are able to study in the polar regions the division of land and sea, 

 the size, elevation, and topography of the land the whole question, 

 in short, of polar geography. The form of the earth's surface is 

 not casual, but is the result of interactions of the crust and the in- 

 terior of the globe. The discovery by Nansen's expedition of the 

 profundity of the polar sea tallies with Prof. Mohn's observations 

 of the great depths between Greenland and Spitzbergen and with 

 those of the fiords and interinsular channels of the North At- 

 lantic. Further, the sea bottoms are penetrated by volcanoes, 

 some of them still active here single, as in Jan Mayen Island, 

 there in groups, as in Franz- Joseph Land and Fire Island. A 

 marked difference exists in this respect between the Atlantic half 

 of the polar regions north of Europe and eastern North America, 

 where disturbance and divisions of the land are the rule, and the 

 Pacific side, north of Siberia and western America, where quiet 

 prevails, with regular coast forms and few islands. The lands on 

 the Atlantic side have, moreover, been gradually rising for an in- 

 calculable length of time, and are still rising, while those on the 

 opposite side have until very recently been subsiding. These 

 facts, selected as examples from a great number of phenomena, 

 may serve to illustrate how important is a knowledge of the polar 

 regions to that of the earth as a whole. Its importance is, in fact, 

 quite beyond comprehension. 



So the magnetism of the earth, the colored beams of the 

 northern lights, the flickering of their draperies and bands, are 

 of interest far beyond their relations to the earth alone ; for the 

 movement of the magnetic elements reflects the processes of the 

 sun's atmosphere, and may be connected with the immense 

 periods of the revolution of our solar system. Man could not 

 refrain from inquiring into the nature and reason of these things 

 even if he would, and hence he is willingly or unwillingly led 

 to the poles, where he is brought into the closest relations with 

 them, and where the explanation of them can be most hopefully 

 sought. 



A relation between the northern lights and the weather has 

 been established by repeated observations, and that brings us to 



