§ 420, 421. THE SPECIFIC GRAVITY OF THE SEA, ETC. 20o 



CHAPTEK IX. 



§ 420-460. — ^THE SPECIFIC GRAVITY OF THE SEA, AND THE 

 OPEN WATER IN THE ARCTIC OCEAN. 



420. The crust of the planet upon whicli we live, "with the 

 Interesting physical foices that have been and are at work upon it, is 

 inquiries. ^]^g j^^g^ interesting subject of physical inquiry and 

 study that can claim the attention of diligent students. Precisely 

 as the progress of man has been upward and onward, precisely 

 has he looked more earnestly and with deeper longings toward 

 the mysteries that encircle this crust. It is but a shell, and at 

 most we can reach only a little way either above or below its very 

 surface, and yet upon the tablets of this thin shell are the records 

 of all that he may ever know concerning this his cosmical hearth- 

 stone. 



421. Eesearches have been carried on from the bottom of the 

 Voyages of discovery dcepcst pit to the top of thc highcst mountain, but 

 to the Nortii Pole. thcsc havc uot Satisfied. Voyages of discovery, 

 with their fascinations and their charms, have led many a noble 

 champion both into the torrid and frigid zones; and notwith- 

 standing the hardships, sufferings, and disasters to which many 

 northern parties have found themselves exposed, seafaring men, 

 as science has advanced, have looked with deeper and deeper 

 longings toward the mystic circles of the polar regions. There 

 icebergs are framed and glaciers launched. There the tides have 

 their cradle, the whales their nursery. There the winds complete 

 their circuits, and the currents of the sea their round in the won- 

 derful system of oceanic circulation. There the Aurora Borealis 

 is lighted up and the trembling needle brought to rest ; and there 

 too, in the mazes of that mystic circle, terrestrial forces of occult 

 power and of vast influence uj^on the well-being of man are con- 

 tinually at play. Within the arctic circle is the pole of the 

 winds and the poles of the cold, the pole of the earth and of 

 the magnet. It is a circle of mysteries ; and the desire to enter 

 it, to explore its untrodden wastes and secret chambers, and to 



