Page:The American Boy's Handy Book edition 1.djvu/120

upon the most improved pattern, and it also shows how serviceable dredges and tangles may be made out of simple materials to be found about any house.

The dredge is an instrument made to drag along the bottom of the water and scoop up the objects, such as corals, sponges, etc., that are found there.

The common oyster dredge is a familiar object at all sea-side places, but it has two or three defects which make it objectionable to the amateur dredger. In the first place, it requires a skilled hand to keep it right side up when in use. Nothing is more discouraging to a beginner than to discover, after a long pull, that on account of the dredge being towed upside down the scraper has been unable to perform its duty. The meshes of an oyster dredge are made very large purposely, that all small objects may slip through. Among these small objects are some of the curiosities most prized by the collector.

To remedy the first defect, the collector's dredge is made with a scraper upon both sides (Fig. 65). The second defect is overcome by using a net with very fine meshes.

The net, if unprotected, would soon be cut and torn into shreds by the sharp-edged shells or rough bottom. To prevent this, it is enclosed in a leather or canvas bag open at both ends (Fig. 65). The dotted line shows the net inside.

The handles and scrapers are composed of iron.

If the machine become fast between the rocks of the bottom, the string that binds the joint marked in the diagram (Fig. 65) will part, thus allowing the machine to turn edgewise and free itself.

Many curious objects were frequently brought up clinging to the cable or the frayed edges of the canvas cover of the dredges first used, and it was noticed that the dredge itself seldom contained any of these objects. This fact gave birth to