592 MISCELLANEOUS 



entrance to the purse. It is at this point the opening of the pockets 

 are placed ; and they are so arranged that the fish having passed into 

 the purse, and then seeking to escape by returning along its sides, are 

 pretty sure to go into the pockets, which extend for a length of about 

 15 or 16 feet along the inner side of the body of the net, and there, 

 the more they try to press forward, the more tightly they become 

 packed, as the pockets gradually narrow away to nothing at their 

 upper extremity. These pockets are not separate parts of the trawl, 

 but are made by merely lacing together the back and belly of the 

 net, beginning close to the margin or side nearly on a level with the 

 bosom, and then carried on with slowly increasing breadth down- 

 wards as far as the entrance to the purse. At this point the breadth 

 of the net is divided into three nearly equal spaces, the central one 

 being the opening from the main body of the net into the purse, or 

 general receptacle for the fish, which must all pass through it, and 

 those on each side being the mouths of the pockets facing the oppo- 

 site direction. The central passage has a valve or veil of netting 

 called the " flapper," which only opens when the fish press against it 

 on their way into the purse. To understand clearly the facilities 

 offered to the fish to enter the pockets, it is necessary to remember 

 that the trawl, when at work, is towed along, with just sufficient 

 force to expand the net by the resistance of the water. But this 

 resistance directly acts only on the interior of the body of the net 

 between the pockets and then on the purse; it does not at first ex- 

 pand the pockets, but tends rather to flatten them, because they are 

 virtually outside the general cavity of the trawl, and their openings 

 face the further end of it. The water, however, which has expanded 

 the body of the net, then passes through the flapper or valve, and 

 enters the purse, which, being made with a much smaller mesh than 

 the rest of the net, offers so much resistance that it cannot readily 

 escape in that direction; return currents are consequently formed 

 along the sides; and those currents open the mouths of the pockets, 

 which as before mentioned, are facing themj and the fish, in their 

 endeavors to escape, and finding these openings, follow the course 

 of the pockets until they can go no farther. The whole of the net 

 is therefore well expanded, but it is so by the pressure of the water 

 in one direction through the middle, and in the opposite direction 

 at the sides or pockets. 



The meshes of an ordinary deep-sea trawl vary in size in different 

 parts of the net, diminishing from 4 inches square near the mouth 

 to 1 inches in the cod or purse. The under part of the net, being 

 exposed to more wear and chafing than the upper, is usually made 

 with rather stouter twine; and the purse, being especially liable 

 to injury from being dragged over the ground with a weight of fish 

 and perhaps stones in it, has some protection provided by lavers 

 of old netting called " rubbing pieces " laced to its under surface. 

 The French fishermen frequently fasten a stout hide to this part of 

 their trawls with the same object. 



A deep-sea trawl, such as has now been described, is therefore an 

 immense beg-net, the largest size being about 50 feet wide at the 

 mouth and about 100 feet long. Many of these nets are much 

 smaller, some of them not having the beam more than 36 feet or 

 even less, and the net reduced in proportion; but there has been a 

 great increase in the size of the trawl- vessels in recent years, and at 



