34 THREE CRUISES OF THE '' BLAKE." 



dredge was over the side, and everything ready for lowering, 

 the reeling-engine was reversed slowly until the trawl was well 

 started, when the lowering could be done somewhat more rap- 

 idly ; and as soon as sufficient wire had been payed out, so 

 that its weight and that of the trawl were great enough to 

 overcome the resistance to the descent of the rope, then steam 

 was shut off and the wire was managed entirely by the fric- 

 tion-brake. During the lowering, the steamer was very slowly 

 backed, and as soon as the trawl was well planted she was 

 backed more rapidly, until, according to the soundings, an ad- 

 ditional amount of rope equal to from a third to twice the 

 depth had been payed out. Then, when the wire rope was 

 well fast, the steamer was backed at the rate of a mile and a 

 half to three miles an hour, according to the nature of the 

 bottom, dragging the trawl for a length of time varying from 

 ten to twenty minutes. In hauling up, the winding-engine was 

 again brought into requisition, great care being taken, when 

 the trawl or dredge broke ground, that the movement should 

 be slow at first when the strain of the trawl and its load came 

 upon the wire rope. 



A new crew requires a little practice to become familiar with 

 the working of the machinery, and in our first attempt off Ha- 

 vana we came to grief by paying out the dredge-rope too fast. 

 This produced a tangle of about two hundred fathoms of steel 

 wire, the cause of which was easily explained when we saw the 

 hopeless result ; but it also taught us the speed at which we 

 should lower and the proper manner of handling the vessel dur- 

 ing the operation, so that the accident was altogether a most 

 fortunate one for the future progress of the work. 



Intimately connected with the fauna of great depths is the 

 pelagic fauna. The innumerable marine animals which always 

 Hve at or near the surface, either during their whole life or 

 merely during their earlier stages of existence, play an impor- 

 tant part in the economy of the deep-water fauna. The surface 

 of the ocean on calm days swarms with pelagic mollusks, Crus- 

 tacea, echinoderms, jelly-fish, and the like, either adults or em- 

 bryos, associated with foraminifera and sponges. The surface 

 animals are collected by means of a hand-net (Fig. 31) made of 



