THE MARINE DREDGE. 43 
The frame, or “scraper” as it is called, Fig. 17, is of iron, is 12 
inches long, 334 inches deep, and 1¥% inches broad. In front, and 
exactly in the middle of the two sides aa, a hole is drilled, into 
each of which a piece of strong iron wire, of the same length as the 
frame, is hooked, and the free end of each piece is bent in the 
form of aring. To the two rings the towing lineis tied. A writer 
in ‘ Science Gossip ” recommends that the line should be attached to 
one ring only, the two rings being tied together with a piece of 
spun yarn: this arranggment being said to facilitate the liberation 
of the dredge when it gets fast to a stone. I have never found any 
difficulty in liberating the dredge by retracing ground, but I am 
assured that the above arrangement is of great utility when work- 
ing over very rocky ground. At the back of the scraper, Fig. 18, 
four holes are drilled on each side, those marked pp receiving the 
Fig. 19. 
ends of the two lengths of strong brass wire, EE, which hold the net 
on to the frame, and into those marked cc, two v shaped pieces of 
brass wire, F, Fig. 19, are fastened, the object of which is to pre- 
vent the scraper from falling on its back, and so closing the mouth 
of the net. The net is an ordinary landing net of the best quality. 
It is important that the material of which the net is made should 
be very strong, on account of the wear and tear to which it is sub- 
jected ; and when new, the mouth should be considerably wider 
than the frame, to allow for the shrinkage which takes place after 
it has been in the water some time. It is also an advantage to 
