114 DISCOVERY REPORTS 



the bucket and the ring and in this position large catches in first-rate condition were 

 obtained in the bucket at all depths down to 2000 m. The modified net in its open and 

 closed positions is shown in Fig. 2. 



With the rope working externally, as described, this is probably the most suitable 

 arrangement that can be contrived for closing such a large net. Where throttling now 

 takes place the circumference of the net is 32 ft., and a drop of 20 ft., which is not unduly 

 large, is required to effect a satisfactory constriction. There is still, after closing, 30 ft. 

 of the forward coarse-meshed end to keep up the even fishing strain, and this not only 

 steadies the collapsed portion tailing out a further 30 ft. astern, but is enough to 

 "float" the heavy ring so that even with the winch stopped there is little fear of its 

 sinking and fouling the warp. The net, of course, is still a double-acting one, yielding 

 large catches in the I in. netting of the forward section. In general condition the front 

 section material is naturally somewhat inferior to that in the bucket, yet the bulk of 

 it is in a very passable state. 



The throttling rope it is true might be moved still farther up the net to operate at its 

 normal position, the canvas band, but for various reasons such an arrangement might 

 not prove altogether satisfactory. In the first place it would be necessary to fall back 

 on an internal rope, and it is rather doubtful if the 50 ft. of material composing the 

 canvas band could be constricted internally without leaving, as already explained, an 

 undesirably large hiatus. Further, apart from the much longer drop that would be 

 required, and the increased risk of straining the gear that this must entail, there would 

 be greater difficulty after closing in controlling the heavy ring, unless it were being 

 hove very fast, for the net behind, being completely collapsed, would no longer impart 

 to it the necessary buoyancy. 



In recent practice the faster oblique method of towing, in which the speed of the ship 

 can be augmented by that of the winch, has superseded the horizontal. The importance 

 of rapid fishing, already suspected, was established at an early stage in these experi- 

 ments, when oblique nets travelling more quickly through the water, but covering com- 

 paratively little ground, produced consistently better results — bigger catches and larger 

 individual animals — than horizontal tows of twice the duration. In spite of its advantage 

 in speed, however, the oblique method has certain obvious limitations, for whereas a 

 horizontal net can be towed indefinitely within the limits of the same restricted horizon, 

 the oblique net, as long as it remains open, must unavoidably widen its horizon, slowly 

 or rapidly according to the speed at which it is being hauled. At first sight therefore it 

 would appear impossible with a fast-moving oblique net to examine a sufficiently narrow 

 horizon without a drastic shortening of the haul — a serious disadvantage, especially 

 when working in deep water, where, since the animal community is so widely scattered, 

 the time of fishing should be as long as possible. 



The tendency of a large fast-moving oblique net to rise through too wide a horizon 

 can however be effectively controlled without unduly curtailing the actual period of the 

 haul. At normal towing speeds of from i to i| knots the N 450, if hauled obliquely, 



