Curiosities of Science. 181 



racters of a nearly homogeneous growth. The iceberg is true 

 ice, and is always dreaded by ships. Indeed, though modified 

 by climate, and especially by the alternation of day and night, 

 the polar glacier must be regarded as strictly atmospheric in 

 its increments, and not essentially differing from the glacier of 

 the Alps. The general appearance of a berg may be compared 

 to frosted silver ; but when its fractures are very extensive, 

 the exposed faces have a very brilliant lustre. Nothing can be 

 more exquisite than a fresh, cleanly fractured berg surface : it 

 reminds one of the recent cleavage of sulphate of strontian a 

 resemblance more striking from the slightly lazulitic tinge of 

 each. U. 8. Grinnel Expedition in Search of Sir J. Franklin. 



IMMENSITY OF POLAR ICE. 



The quantity of solid matter that is drifted out of the 

 Polar Seas through one opening Davis's Straits alone, and 

 during a part of the year only, covers to the depth of seven 

 feet an area of 3uO,000 square miles, and weighs not less than 

 18,000,000,000 tons. The quantity of water required to float 

 and drive out this solid matter is probably many times greater 

 than this. A quantity of water equal in weight to these two 

 masses has to go in. The basin to receive these inflowing wa- 

 ters, i. e. the unexplored basin about the North Pole, includes 

 an area of 1,500,000 square miles; and as the outflowing ice 

 and water are at the surface, the return current must be sub- 

 marine. 



These two currents, therefore, it may be perceived, keep in 

 motion between the temperate and polar regions of the earth a 

 volume of water, in comparison with which the mighty Missis- 

 sippi in its greatest floods sinks down to a mere rill. Maury. 



OPEN SEA AT THE POLE. 



The following fact is striking : In 1662-3, Mr. Oldenburg, 

 Secretary to the Royal Society, was ordered to register a paper 

 entitled " Several Inquiries concerning Greenland, answered by 

 Mr. Gray, who had visited those parts. " The nineteenth query 

 was, " How near any one hath been known to approach the Pole. 

 Answer. I once met upon the coast of Greenland a Hollander, 

 that swore he had been but half a degree from the Pole, show- 

 ing me his journal, which was also attested by his mate; where 

 they had seen no ice or land, but all water." Boyle mentions 

 a similar account, which he received from an old Greenland 

 master, on April 5, 1765. 



RIVER- WATER ON THE OCEAN. 



Captain Sabine found discoloured water, supposed to be 

 that of the Amazon, 300 miles distant in the ocean from the 



