. Bulletin - United States National Museum. Science. [27] INSTRUCTIONS FOR COLLECTING MOLLUSKS DALL. rectangle. The lower and upper edges in front are liamiuered so as to flare a little, like the edge of a chisel, [a, a, Fig. 2) thus plowing up the Ibottom over which the dredge is pulled. The edges of the short verti- cal sides are left without this bevel. In each side are two holes, (h, h, Fig. 3) in which are inserted the Y-shaped ends of the arm (Fig. 5) of each side, made of a slender (about three-eighths of an inch) iron rod. The anterior part of each arm ends in a ring formed by turning
. Bulletin - United States National Museum. Science. [27] INSTRUCTIONS FOR COLLECTING MOLLUSKS DALL. rectangle. The lower and upper edges in front are liamiuered so as to flare a little, like the edge of a chisel, [a, a, Fig. 2) thus plowing up the Ibottom over which the dredge is pulled. The edges of the short verti- cal sides are left without this bevel. In each side are two holes, (h, h, Fig. 3) in which are inserted the Y-shaped ends of the arm (Fig. 5) of each side, made of a slender (about three-eighths of an inch) iron rod. The anterior part of each arm ends in a ring formed by turning the end of the rod round. Parallel with and near to the back edges of the frame is punched a row of holes, as many as may be convenient. By means. oh o^ /a^ h Tigs. 1 and 3.—Dredge frame. of rivets through these holes a thin strip of galvanized iron is attached, extending, on the outside, entirely around the back edge of the rectangle. The hinder edge of the galvanized iron extends about an inch behind the hinder edge of the frame. This is perforated with a row of small holes about an inch apart, extending entirely around the edge. To these holes a net (fZ, Fig. 2) and two flaps of stout canvas {c^ (?, Fig. 2) are laced with copper or galvanized iron wire. The object of the strip of galvanized iron is to hold the net away from the iron frame, which always rusts. This rust would very soon destroy the net, but if the latter is separated from the iron by the galvanized strip which does not rust, a single net may sometimes be used for a whole season, without need of repair. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States National Museum; Smithsonian Institution; United States. Dept. of the Interior. Washington : Smithsonian Institution Press, [etc. ]; for sale by the Supt. of Docs. , U. S. G
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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
