246 THE PHYSICAL GEOGRAPHY OF THE SEA. 



raise the question in speculative minds, Is gravitation a universal 

 thing, and do its forces penetrate every aT3yss of space ? 



687. Could we not gauge the sea as well as the sky, and de- 

 vise an instrument for penetrating the depths of the ocean as well 

 as the depths of space ? j\Iariners were curious concerning the 

 bottom of the sea. Though nothing thence had been brought to 

 light, exploration had invested the subject with additional inter- 

 est, and increased the deske to know more. In this state of the 

 case, the idea of a common twine thread for a sounding-line, and a 

 cannon ball for a sinker, was suggested. It was a beautiful con- 

 ception ; for, besides its simplicity, it had in its favor the greatest 

 of recommendations — it could be readily put into practice. 



Well-directed attempts to fathom the ocean began now to be 

 made with such a line and plummet, and the public mind was as- 

 tonished at the vast de23ths that were at first reported. 



688. Lieutenant Walsh, of the United States schooner "Taney," 

 reported a cast with the deep-sea lead at thirty-four thousand feet 

 without bottom. His sounding-line was an iron wire more than 

 eleven miles in length. Lieutenant Berry man, of the United 

 States brig "Dolphin," reported another unsuccessful attempt to 

 fathom mid-ocean with a line thirty-nine thousand feet in length. 

 Captain Denham, of her Britannic majesty's ship " Herald," re- 

 ported bottom in the South Atlantic at the depth of forty-six 

 thousand feet ; and Lieutenant J. P. Parker, of the United States 

 frigate " Congress," afterward, in attempting to sound near the 

 same region, let go his plummet, and saw it run out a line fifty 

 thousand feet long as though the bottom had not been reached. 



689. The three last-named attempts were made with the sound- 

 ing twine of the American Navy, which has been introduced in 

 conformity with a very simple plan for sounding out the depths of 

 the ocean. It involved for each cast only the expenditure of a 

 cannon ball, and twine enough to reach the bottom. This plan 

 was introduced as a part of the researches conducted at the Na- 

 tional Observatory, and which have proved so fruitful and bene- 

 ficial, concerning the winds and currents, and other phenomena 

 of the ocean. These researches had already received the appro- 

 bation of the Congress of the United States ; for that body, in a 



