242 THE DEPTHS OF THE SEA. [CHAP. vi. 



round iron of the same thickness, dividing beneath 

 into two branches which are attached to the ends of 

 the cross-bars by eyes allowing the arms to fold down 

 over the dredge- mouth, meet in two heavy eyes at a 

 point eighteen inches above the centre of the frame. 

 The total weight of the dredge-frame and arms is 

 twenty pounds. It ought to be of the best Low- 

 moor on Swedish wrought-iron. I have seen a stout 

 dredge-frame of Lowmoor iron twisted like a bit 

 of wax in extricating it from a jam between two 

 stones, and, singularly enough, the dredge which 

 came up in that condition contained the unique 

 example of an echinoderm never found before or 

 since. 



The thick inner edges of the scrapers are perforated 

 by round holes at distances of about an inch, and 

 through these, strong iron rings about an inch in 

 diameter are passed, and two or three like rings run 

 on the short rods which form the ends of the dredge- 

 frame. A light iron rod bent to the form of the 

 dredge opening usually runs through these rings, and 

 to this rod and to the rings the mouth of the dredge- 

 bag is securely attached by stout cord or strong 

 copper wire. 



In the dredge now before me, which has worked 

 w r ell and seen good service, the bag is two feet in 

 depth, and is of hand-made net of very strong twine, 

 the meshes half an inch to the side. So open 

 a network would let many of the smaller things 

 through, and to avoid this the bottom of the bag, to 

 the height of about nine inches, is lined with ' bread- 

 bag/ a light open kind of canvas. 



Many other materials have been used for dredge- 



