! 
OF THE DREDGE. 109 
always open, of which the edges have been attached, as we 
have said, one end to the back plate, B C, and the other to the 
transverse rod or bar, 6 c. 
This rod must be firmly fixed in its place; for this purpose, 
it is a little flattened, and pierced in its middle, D, with a hole. 
A bar, A D, figs. 1. and 2., which comes from the summit, A, 
of the dredge, and which is also flattened and pierced with a 
hole at its extremity, D, is joined, by means of that extremity, 
to the middle of the rod, bc, on the concave side, so that the 
two holes are adapted to each other. The extremity of a small 
cross bar of iron, Df is made to pass these, which issues by 
the other side of the rod, bc, and the bar, AD. The same 
cross piece of iron, Df, is attached, in a similar manner, by iis 
other extremity, 4, which is made to pass, that it may be after- 
_ wards bent, through one of the holes, with which the back of 
the plate, B C, is pierced. 
This plate, as we before mentioned, is pierced with eleven 
holes, of which eight only are employed in giving passage te 
the meshes of the net or bag. These holes are arranged twe 
and two together: an idea of their arrangement, and the use of | 
the three others, may be learnt by inspecting fig. 1. That in 
the middle serves to attach the cross bar, D£ The two others 
serve to attach, in like manner, two similar cross bars, dd, dd, 
fig. 1., which strengthen the whole machine, and of which the 
other extremity is attached to the rod, bc, by a kind of hook, 
which embraces that rod. 
The bar, A D, and the cross bar, D f, are inclined to one 
another. By means of this inclination, the bar A D, through 
which passes the cross bar D f, is strongly fixed to the rod 
| bc, from which it can be removed only by being elongated, 
This bar, A D, is a little less thick than the two ascending 
branches A B, A C; they are, however, nearly two inches in 
diameter. The three branches, A B, A C, A D, unite again 
at the summit of the dredge, where they are welded together 
so as to make only one, whose extremity is bent to embrace the 
ring, as seen at A, figs. 1. and 2. The common oyster dredge 
is smaller than that which we have described, and of a lighter 
make. 
We have still to describe the manner in which this instru- 
ment is used for the fishing of shells. A cord is passed through 
K 
