116 LIGHT SCIENCE FOR LEISURE HOURS. 



make their way, have become gradually less and less 

 firm, until at length no doubt could remain that there 



7 O 



lay an open sea beyond them. How far that sea may 

 extend is a part of the secret of the North Pole ; but 

 we may assume that it is no narrow sea, since other- 

 wise there can be little doubt that the ice-fields which 

 surround the shores of Northern Siberia would extend 

 unbroken to the farther shores of what we should thus 

 have to recognize as a strait. The thinning-ofF of these 

 ice-fields, observed by Baron "Wrangel and his com- 

 panions, affords, indeed, most remarkable and signifi- 

 cant testimony respecting the nature of the sea which 

 lies beyond. This we shall presently have to exhibit 

 more at length ; in the mean time we need only remark 

 that scarcely any doubt can exist that the sea thus 

 discovered extends northward to at least the eightieth 

 parallel of latitude. 



"We may say, then, that from Wellington Channel, 

 northward of the American Continent, right round 

 toward the west, up to the neighborhood of Spitz- 

 bergen, very little doubt exists as to the general 

 characteristics of arctic regions, save only as respects 

 those unexplored parts which lie within ten or twelve 

 degrees of the North Pole. The reader will see pres- 

 ently why we are so careful to exhibit the limited 

 extent of the unexplored arctic regions in this direction. 

 The guess we shall form as to the true nature of the 

 north-polar secret will depend almost entirely on this 

 consideration. 



