62« DEEP-SEA SOUNDING. 



is of a negative character ; for it is evident that the wire would be carried 

 down and run out by its own weight. 



One of the earHest specimens of bottom obtained at great depths was 

 by Commander C. H. Davis, U.S.N., in October, 1845, when greenish mud 

 was brought up in the " Stellwagen cup" from a depth of 1,350 fathoms, in 

 the Gulf Stream. In 1850 — 1851, the United States Government des- 

 patched the sloop Albany, Captain Pratt, to continue the work of sound- 

 ing the depths of the Atlantic, and numerous soundings were made in 

 depths up to 1,280 fathoms. 



The possibility of obtaining a knowledge of the great depth of the ocean 

 being established, the United States Government first commenced utilising 

 this knowledge, on a more extended scale, by the expedition of the brig 

 Dolphin, in 1851 — 1852, under the command of Lieut. Lee, and afterwards 

 of Lieut. 0. H. Berryman. The result of this voyage was the disproof of 

 the existence, in their reported positions, of many of those shoals and 

 dangers which had long held a place on our charts, to the continual annoy- 

 ance and embarrassment of navigation, as recited in previous pages. The 

 cruise of the Dolphin was confined to the North Atlantic Ocean, except a 

 portion in South latitude about Fernando Noronha and the Eocas. 



The question of connecting Europe and America by submarine electric 

 telegraph now brought the subject of the depth of the ocean prominently 

 to the fore, and the first trustworthy and systematic series of soundings, 

 24 in number, was obtained by Lieut. 0. H. Berryman, in the U.S. steamer 

 Arctic, in August, 1856, on the great circle joining Valentia, Ireland, with 

 St. John's, Newfoundland. The depths were estimated by a Massey's 

 Sounding Machine, and a similar one by M. Lecointre, and the line was 

 wound in by a small engine on the deck. 



The same round was gone over, with the same object, by Lieut. J. 

 Dayman, in H.M.S. Cyclops, in June and July, 1857, and 34 soundings 

 were obtained, the depths being estimated by the length of line and by 

 the machine as heretofore. The sinker employed was self- detaching upon 

 touching the bottom, and in a quill attached to the support, samples of 

 the bottom were brought up in almost every instance in small quantities. 

 The nature of these specimens is alluded to hereafter, and the very inter- 

 esting features it first brought to light are there related. 



The first failure of the Atlantic Cable having suggested the necessity of 

 shorter sea sections of the cable, Lieut. Dayman was despatched in 

 H.M.S. Gorgon, in September and October, 1858, and obtained soundings 

 between Newfoundland, the Azores, and England, gaining much experience 

 as to the best methods of sounding, and also of estimating the depths. 



Another project for the telegraph cable, to pursue a more northern route, 

 having arisen, in July, 1860, H.M.S. Bulldog started under the command 

 of Admiral Sir Leopold M'CHntock, of Arctic celebrity, and obtained the 

 depths between the Faeroe Islands and Iceland, and thence to Greenland 

 and Labrador, with most satisfactory results. 



The subject of the Atlantic telegraph cable being still of great importance, 

 and it being desirable that the apparent sudden dip from 550 to 1,750^ 

 fathoms on the parallel of 52° 15' N., at about 170 miles West of Valentia, 

 found by Lieut. Dayman, in 1857, should be avoided, H.M.S. Porcupine 



