CHAP, v.] DEEP-SEA SOUNDING. 229 



and currents, and filling up liollows by drifting about 

 and distributing their materials. 



The first careful surveys of the Atlantic, in which 

 great depths were determined with considerable accu- 

 racy, are the cruises of Lieut. -Commanding Lee, in 

 the U.S. brig ' Dolphin ' (1851-52), and of Lieut.- 

 Commanding O. H. Berry man, in the same vessel 

 in 1852-53 ; but the sounding voyage in which 

 modern appliances were first employed with perfect 

 accuracy with a practical object was that of Lieu- 

 tenant Berryman in 1856, in the U.S. steamer 

 ' Arctic,' in which twenty-four deep-sea soundings 

 were taken with the Brooke's and Massey's sounding 

 machines on a great circle between St. John's, New- 

 foundland, and Valentia in Ireland, with a view 

 to the laying of the first cable. The same ground 

 was gone over by Lieutenant Dayman, in H.M.S. 

 'Cyclops,' in June and July 1857, and thirty-four 

 soundings were taken, the depth being estimated by 

 Massey's sounding-machine and a modification of 

 Brooke's machine already described. The next im- 

 portant sounding expedition was that of Commander 

 Dayman, in H.M.S. ' Gorgon,' from Newfoundland to 

 the Agores, and thence to England. The depths 

 were taken in this case with a lead usually 188 lbs. 

 in weight which was lost at each cast, and alba- 

 core line with a breaking strain of 420 lbs. Only 

 on one occasion, about a third of the way from the 

 Agores to England, a cup-lead was let go, attached 

 to a stronger line, in 1,900 fathoms, and came up half 

 filled with grey ooze. 



Another route for a telegraph cable having been pro- 

 posed, H.M.S. 'Bull-dog' started in July 1860, under 



