316 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Cordova. A preliminary discussion of these observations 

 seems to indicate an error in the received longitudes of the 

 east coast of South America of about twelve seconds of time. 



An interesting chain of deep-sea soundings has been made 

 by Commander Schley, U.S.N., in the U.S.S. Essex, from St. 

 Paul de Loando, by way of St. Helena, to Cape Frio, Brazil. 

 Thirty-nine satisfactory soundings were made at an average 

 distance apart of one hundred miles, serial temperatures and 

 bottom specimens being everywhere obtained. The depths 

 and temperatures harmonize perfectly with those obtained 

 by the Challenger and Gazelle in the same region. The bot- 

 tom specimens have been sent to Professor Hamilton Smith, 

 of Hobart College, for examination. 



The profile of this cross-section shows that the depth in- 

 creases quite suddenly on leaving the African shore, 2200 

 fathoms being found 100 miles west of St. Paul de Loando, 

 between which point and St. Helena the greatest depth is 

 3063 fathoms. The island of St. Helena is a mere pinnacle 

 of rock, rising from a base only 30 miles wide to a height of 

 16,000 feet. Five hundred and fifty miles west of St. Hele- 

 na, the elevated ridge spoken of by Sir Wyville Thomson was 

 found with a depth of 1365 fathoms on it, 2300 fathoms being 

 found on its eastern and 2700 fathoms on its western limit. 



From the large number of deep-sea soundings made within 

 the past few years, Dr. Krummel has attempted to make a 

 new approximation to the mean depth of the sea, and has 

 communicated an account of his labors in a note to the Got- 

 tingen Academy. Soundings are wanting for the Antarctic 

 Ocean, and for a part of the North Polar Sea, embracing in 

 all about 475,000 square miles, or about 7 per cent, of the 

 entire sea surface. From available data, however, he deduces 

 a mean depth of 1877 fathoms, the greatest depth yet meas- 

 ured in a trustworthy manner, and from which the bottom 

 was brought up, being 4356 fathoms, found by Captain Bel- 

 knap, U.S.N., off the coast of Japan. 



Ilydrographic work on the Atlantic, Gulf, and Pacific coasts 

 of the United States has been carried on extensively by the 

 United States Coast Survey; the actual work on board ship 

 having been in nearly, or quite, all cases performed by officers 

 and men of the United States Navy. 



In the steamer Blake, Lieut.-Commander Sigsbee, U.S.N. , 



