588 



U. S. BUREAU OF FISHERIES 



without hindering the free circulation 

 of brine. The endless chains and 

 netting are supported by two drums, 

 one of which is connected with a 

 gear by which the whole system is 

 set in motion. 



At distances of 3 feet 6 inches the 

 links of the chains carry light iron 

 frames, on which netting is stretched, 

 thus forming a kind of paddle, the 

 apparatus having to some extent the 

 appearance of a caterpillar tractor, 

 the paddles, however, being of excep- 

 tionally large size. The whole appa- 

 ratus is immersed in a brine tank up 

 to the axle of the drum. 



At a small distance from the lower 

 part of the endless net are placed 

 lines of cocks with their apertures, 

 underneath, by which cold brine from 

 a double-pipe brine cooler enters the 

 tank at a certain pressure, causing 

 sufficient agitation in the whole body 

 of brine. 



The drums, chains, and netting be- 

 ing set in motion at very slow speed, 

 a crate of fish just landed from the 

 trawler is. emptied in the tank at one 

 end: the fish are caught beneath a 

 paddle and gently dipped into the 

 brine. When the paddle has passed 

 the vertical plane, the fish, on account 

 of their density being less than that 

 of the brine, begin to float in the 

 liquid and adhere to the underside of 

 the netting. The motion caused in 

 the water by the lines of cocks pre- 

 vents the fish forming thick masses 

 from which heat could not be elimi- 

 nated and spreads them thinly under- 

 neath the netting. The fish are thus 

 slowly moved in gently agitated brine 

 from one end of the tank to the 

 other, where they arrive frozen hard ; 

 they are then taken out, packed in 

 convenient cases, and placed in cold 

 storage. The motion of the netting 

 and the paddles is so slow and gentle 

 that in no case can the skin or scales 

 of the fish be injured, and special 

 fittings are provided with a view to 

 prevent any fish being caught and 

 pressed between the paddles and the 

 walls of the tank. 



Except at the ends, where the fish 

 are dropped in or picked out, the 

 tank is covered to avoid any undue 

 loss of cold, and, of course, the 

 whole external surface of the tank is 

 thickly insulated. The excess of 

 brine coming from the tank is passed 

 through a settling tank, then pumped 

 through a filter to take out dirt, 

 scales, or mucus, after which it passes 

 through the brine cooler and back 

 again to the freezing tank. The out- 

 put of a tank supplied with fish up 



