CONSERVATION OF DEEP SEA BEDS. 1043 



scraper is called the " bit " or " knife," and to its ends are 

 welded two iron rods ; these, after curving to form the 

 narrow sides of the mouth, are united together and form 

 two sides of a triangle, which is bisected by a strengthening 

 piece, the base of the triangle being made by a piece of 

 iron called the " warbin ;" this is welded into each side, its 

 apex fitted with a shoulder for convenience of working on 

 the gunwale, and with a ring to which the dredge-rope is 

 made fast. 



The free ends of the bag are fastened to three pieces 

 of wood, the "side-sticks' 3 and "catch-stick;" the side- 

 sticks help to distend the bag, and the catch-stick gives a 

 convenient hold when the bag is turned out. 



A great deal of skill is necessary in using the dredge, 

 and the greatest attention must be made to the force and 

 direction of the wind and tide ; but of that more hereafter. 



The size of the. iron rings forming the under side of the 

 bag are regulated by the size of the ring which in certain 

 localities is used for measuring the oysters ; those that pass 

 through the ring being unmarketable. 



The meshes of the netting forming the other side are 

 of about two inches square. 



Where the grounds are occasionally rocky, or where 

 large stones are sometimes found, the dredge-rope is first 

 shackled into the left lower edge of the framework ; it is 

 then brought along the middle-bar, and a clove-hitch 

 taken round it with a strong, thin piece of hide, about six 

 inches below the ring ; the rope is then stopped to the 

 ring with a piece of spun yarn, leaving a few inches of 

 slack between the hide and the ring. The dredge, thus 

 fitted, hangs square until it meets an impediment ; on it 

 " setting" fast, the spun yarn breaks, the rope slips through 



