Fish are also dried in some factories in large, steam-heated shelf driers. This method is inclined to be too rapid, with the result that the fish are only surface dried instead of being uniformly dried right through. After drying, the fish are kenched in the store until required. They are then skinned, the bones are removed, and they are moulded into blocks which are cut up into cakes for packing and export. It is estimated that the loss in weight during the different operations is as follows— Dressing 40 per cent Salting (full pickle) 17 „ Drying 4 „ Skinning and boning 13 „ ----------- Total loss 74 „ =========== The fresh waste, skins, bones, etc., of the fish are worked up for glue, the residue being manufactured into fertilizer. The best glue is obtained from the skins. The cod and cusk skins are superior in this to the skins of hake and haddock. The oil is extracted from the livers. That from fresh livers is refined and used for medicinal purposes, while that from old livers is used for tanning chamois leather. The value of this oil is considerable, as much as £150 being received by a boat in one trip for the oil alone. In 1914, Newfoundland exported 60,000 tons of cod meat, worth £1,600,000. The chief market is the Mediterranean. CHAPTER VI TRAWL FISHERIES Unlike the drift net, which only catches fish of one species and of fairly uniform size when they are swimming near the surface, the trawl net scoops up practically all the inhabitants of the sea bottom, including round fish, e.g. cod and haddock; flat fish, e.g. sole and plaice, as well as various invertebrates (jelly fish), and marine plants and stones. The trawl is essentially a flattened, conical net that is dragged open-mouthed along the sea bottom. The two kinds of trawl in common use—the beam trawl and the otter trawl—differ in the method that is adopted for keeping open the mouth of the net. The beam trawl is used by sailing vessels, the otter trawl by steamers. Sailing trawlers are divided into two classes: first class smacks and second class cutters. The smack is a two masted vessel with fore and aft rig, generally making a five or six day voyage, and trawling in depths of up to 40 fathoms. The cutter makes shorter voyages—20 hours—and generally keeps within territorial waters.