406 



Messrs. Carpenter, Jeffreys, and Thomson [Nov. 18, 



5. Every one of the numerous deep Soundings obtained in this Expedi- 

 tion was taken, not only under the superintendence, but actually by the 

 hands, of Capt. Calver himself; of whose skill in the conduct of this ope- 

 ration (which often requires great nicety in the management of the 

 vessel, so as to secure a good up-and-down direction of the "line) it is 

 enough to say that it is worthy of the distinguished Service to which he 

 belongs, and to his high position in it. Not a single fathom of line has 

 been lost, and not a single instrument has suffered damage, throughout the 

 whole Expedition. 



6. The Dredges supplied to the ' Porcupine 9 by the Admiralty were con- 

 structed upon the model of those which were found to work best in the 

 'Lightning' Expedition. The experience of the First Cruise, however, in 

 which the dredging was carried down to more than twice the depth attained 

 last year, led Capt. Calver to have a still heavier dredge constructed at 

 Belfast, upon a somewhat different pattern ; and it was with this that the 

 very deep Dredgings of the Second cruise were executed, by which the con- 

 dition of the sea-bottom was successfully investigated at a depth of 2435 

 fathoms (§§ 45-50)*. An ample supply of strong Dredge-rope was pro- 

 vided ; and a very simple and convenient arrangement was devised by Capt. 

 Calver for hanging this in coils upon pins attached to the inner side of the 

 quarter-deck bulwarks (§ 46), so that the three nautical miles of line 

 required for the deepest Dredging could be thus disposed without at all 

 encumbering the deck, and in a manner which enabled it to be most con- 

 veniently handled both in paying-out and reeling-in, with the additional 

 advantage of keeping it remarkably free from " kinks/' 



7. An importaut addition to the Dredging-apparatus, which was devised 

 by Capt. Calver before the commencement of the Third cruise, will be 

 described in its proper place (§ 63). The result of its employment was 

 so extraordinary, that no deep dredging can hereafter be accounted of any 

 value in which it has not been used ; and it is only now to be regretted 

 that the idea had not presented itself earlier, so as to have been carried out 

 in the First and Second Cruises. 



8. The whole of this equipment would have been ineffective if a suitable 

 Donkey-engine had not been supplied for working it. The experience of 

 the ' Lightning ' had shown that a single-cylinder engine is not adapted for 

 this purpose, being liable to stop at either end of its stroke when a heavy 

 strain is put on the drum, and then moving onwards with a jerk, so as to 

 throw on the line a tension which may very probably cause it to part. It 

 was therefore urged upon the Authorities at Woolwich that a double- 

 cylinder engine should be supplied to the 'Porcupine'; and a 'donkey' on 

 this plan was accordingly fixed, which proved most efficient. Nothing 

 could exceed the steadiness of its working, or the facility with which its 

 speed and power could be regulated in accordance with the purposes to 



* This is nearly equal to the height of Mont Blanc ; and exceeds by more than 500 

 fathoms the depth from which the Atlantic Cable was brought to the surface. 



