possession of the mighty sea. The greater the recess of the tide, the more curious, varied, and abundant are the creatures he discovers;—if then any mode could be devised to scrape the floor of the sea itself at different depths, and to secure the materials thus collected, how important might be the result. The dredge is the implement that does this. It is a strong bag with an iron frame around the mouth, which is dragged over the sea-bottom by a rope fastened to the boat, by which also it is drawn in when full.
The rudest form of the instrument is that used for procuring oysters for market. The bag is generally made of iron rings linked together, and the mouth, which is a four-sided frame of iron, has one of the longer sides turned out to form a scraping lip. But the naturalist's dredge is an improvement upon this form; the oyster-dredge, with all the care employed in heaving, will frequently turn over in sinking, so that the unlipped side of the frame is on the ground, which will not scrape. Hence we have each of the two long sides of the mouth made into a scraping lip, so that the instrument cannot fall wrong. Instead of rings our body is made of spunyarn (a sort of small rope), or fishing-line, netted with a small mesh, or, which is better still, of a raw hide, (such as those which the tobacconists receive from South America inclosing tobacco, the hides of the wild cattle of the Pampas) cut into thongs, and netted in like manner. Sometimes the bag is made of coarse sackcloth, or of canvass, but the former soon wears out, and the latter is not sufficiently pervious to water; an important point, for if there be not a free current through the bag, while on
