164 COLLECTING AND CLEANING SHELLS. 



tlirough 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, D/. The two others 

 serve to attach in like manner, two similar cross bars, d d, d d, 

 fig. 1., which strengthen the whole machine, and of which the 

 other extremity is attached to the rod, b c, hy a. kind of hook, 

 which embraces that rod. 



The bar, A D, and the cross bar, D/ 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 

 b 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 

 the ring attached to the point of the dredge, another cord is 

 attached to the middle of the rod, 6 c, by a knot which em- 

 braces the rod b c, the perpendicular branch A D, and the 

 small cross-bar D /at the point where they unite„ When the 

 boat has reached the place of fishing, the dredge is thrown 

 cut at the stern in the same manner in which an anchor is 

 thrown out, the last named cord serves to keep the dredge in 

 its place, the plate being turned below till it arive at the bot- 

 tom of the sea, and to prevent it from being overturned by the 

 way. When the dredge has reached the bottom, it is hauled 

 along by rowing and sailing. Should the dredge be stopped 

 by any rock or irregularity at the bottom, the rope attached to 

 the ring should be pulled. When the bag is supposed to be full, 



