DEEP-SEA SOUNDING. 



INTRODUCTION. 



Standing against the wall of the Hydrographic Office 

 are two large plaster casts showing the contour of the 

 bottoms of the North and South Atlantic Oceans with 

 their submarine peaks, plateaux, and depressions as 

 revealed by deep-sea soundings. Prominent thereon 

 are two submarine peaks in the South Atlantic Ocean 

 and an extensive sand-bank several hundred miles from 

 the coast of South America, which were discovered by 

 the Enterprise while on a cruise around the world from 

 1883 to 1886 when deep-sea soundings were taken across 

 the Atlantic, Indian, and South Pacific oceans. There 

 is also shown to the northward of Porto Rico the deepest 

 depression yet discovered in the North Atlantic, and into 

 this the Enterprise sounded, bringing up a specimen of 

 the bottom from a depth of 4529 fathoms, the position 

 of the cast being within 40 miles of that taken by Com- 

 mander Brownson in the Blake, which showed a depth 

 of 4561 fathoms and which to this day remains the deep- 

 est cast ever taken in the Atlantic Ocean. 



