COLLECTING SHELLS. 



211 



covered, which inhabit the mighty deep. Indeed we may 

 be said to know scarcely anything of the marine natural 

 history of foreign lands, as few or none of them have been 

 assiduously explored by the dredge. The following is a 

 representation of that instrument. 



To have a clear idea of the dredge, and the parts which 

 compose it, we must imagine a round bar of iron, forged in 

 the shape of an almost equilateral triangle. A, B, C, of the 

 above figure, and having its two extremities joined at A. To 

 form the summit or point of the triangle, each of the sides 

 should be above five feet. The two branches, A B, and 

 A C, are rounded and bent, as they approach the base of the 

 triangle. The base, B C, is forged into a plate, six inches 

 in breadth, with a sharp cutting edge in front, turned up- 

 wards at an angle of about sixty degrees. The back, or that 

 part opposed to the edge of the plate, is an inch thick. By 



