1^30 THE DEPTHS OF THE SEA. [chap. v. 



the command of Captain Sir Leopold M'Clintock, and 

 took depths between the Eaeroe Islands and Iceland, 

 and thence to Greenland and Labrador. The sound- 

 ings were taken first by cod-line and an iron sinker 

 of about 1 cwt., the line and sinker being cut off at 

 each operation ; and the sounding was then usually- 

 repeated with the ' Bull-dog ' sounding-machine, with 

 Avhich large samples of the bottom were procured. 

 A diary of this voyage was kept by Dr. Wallich, 

 Naturalist to the Expedition, and Avas afterwards 

 published by him as part of the extremely important 

 memoir on the North Atlantic sea-bed, to which 

 I have already refeiTcd. Some further questions 

 having arisen as to the best line to be taken by 

 an Atlantic telegraph cable. Captain Hoskyn, E.N., 

 was despatched in the ' Porcupine ' to examine the 

 curious dip from 550 to 1,750 fathoms, described 

 by Captain Dayman in 1857 as occurring about 170 

 miles west of Valentia. One important result of this 

 cruise was the discovery of the ' Porcupine ' Bank, 

 about 120 miles west from Galwrsy Bay, with a mini- 

 raum depth of 82 fathoms. 



Towards the latter part of the year 1868 H.M.S. 

 ' Gannet,' Commander W. Chimmo, R.N., was 

 ordered by the Admiralty to define during her 

 homeward voyage from the "West India Station 

 the northern limits of the Gulf Stream, and to 

 take deep soundings and temjoeratures. Thirteen 

 soundings were taken with the Brooke's machine 

 over an area of upwards of 10,000 square miles 

 from Sable Island (lat. 43" 20' N., long.^60° W.), at 

 depths varying from 80 to 2,700 fathoms. 



Por many years past the American Government 



