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, b 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, b c, 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, b c, and the bar, A D. The same 

 cross piece of iron, D/, is attached, in a similar manner, by its 

 other extremity, y; 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 to 

 the meshes of the net or bag. These holes are arranged two 

 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, Df. 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, & c, 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 /, is strongly fixed to the rod 

 6 c, 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 



