September 12, 1884.] 



SCIENCE 



227 



The runner- frames, made of bar-iron half 

 an inch thick by three inches wide, form a 

 very broad D-shaped figure, being equally 

 curved above and below in front, and extend- 

 ing thence straight back to the upright binder 

 end, beyond which the runners project slight- 

 ly, the overlapping portions being perforated 

 for the attachment of the net. These frames 

 measure three feet and a half in height by 

 four feet in length, and are rigidly connected 

 by two beams of iron gas-pipe, ten feet and 

 three-quarters long and two inches and a 

 quarter in diameter, which screw into brass 

 collars riveted to the inner sides of the run- 

 ners. — one in front, and one behind. The 

 net, like the frame, is perfectly symmetrical in 

 shape, and consists of a cylindrical or slightly 

 conical bag of stout twine webbing, open at the 

 lower end. Its length may vary from eighteen 

 to twenty-five feet ; and, to give it increased 

 strength, a double thickness of webbing is 

 generally emploj'ed. The folds formed in 

 tying the lower end of the net for use serve 

 to retain a certain quantity of the fine bottom- 

 material. 



The method of attaching the net to the 

 runner-frame is simple. A two-and-a-quarter- 

 inch rope runs around the entire mouth, and 

 is laced to the hinder ends of the runners, and 

 secured to the four hinder corners of the same. 

 In common with the mouth of the net, this 

 rope is left sufficiently slack between the 

 runners on both sides ; so that, whichever side 

 is uppermost, the slack of that side curves 

 down to the level of the beams, and does not 

 obstruct the lower half of the opening : the 

 lower slack line naturally curves backward 

 upon the ground. These slack portions of the 

 line are weighted to serve as lead lines. 



There is an inner pocket, or trap, to the net, 

 and a series of four glass or cork floats to 

 assist in keeping it expanded. The runner- 

 openings, and the space between the beams, are 

 also closed in with netting. The bridle for the 

 attachment of the drag-rope may be fastened 

 to the fronts of the runners, or carried back to 

 the hinder end of the net, as before explained. 

 Other methods of arranging the net have been 

 tried, but that above described has proved 

 most satisfactory. 



Trawl-wings. 



It has long been observed, that enormous 

 quantities of small and delicate free-swim- 

 ming animals, especially Crustacea of the lower 

 orders, come up completely crushed in the 

 mass of material which frequently fills the 



trawl ; and it was also evident that still larger 

 quantities must escape through the coarse 

 meshes of the net. To collect and preserve 

 these forms, Capt. H. C. Chester arranged in 

 1880 for the use of the fish-commission, in 

 connection with the beam-trawls, a large tow- 

 ing-net, having a rectangular mouth-frame of 

 iron three feet long by eight inches wide, and 

 a moderately fine mesh bag of netting about 

 three feet in length. Into the lower end of 

 this bag is fitted one of the ordinary silk or 

 linen towing-nets for the purpose of retaining 

 the very smallest objects. Two of these tow- 

 ing-nets are fastened to each trawl of either 

 pattern nearly every time they are used ; being 

 attached, one at each end of the beam (as 

 shown in fig. 3) , by means of a piece of small 



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Fig. 3. — The trawl-wings attached to the beam-trawl> 

 in use. 



gas-pipe lashed by one end to the beam, or 

 extending a short distance into it, if the latter 

 is also of iron. The trawl- wings, as these 

 nets have been christened, give such excellent 

 results, that their appearance at the surface, 

 after a haul, is as anxiously watched for as is 

 that of the trawl proper. 



Tangles. 



While the use of hempen tangle-swabs at- 

 tached to the dredge was introduced b} T the 

 English exploring-steamer Porcupine in 1868 

 or 1869, the idea that they were worthy of be- 

 ing used separately appears to have originated 

 with Professor Verrill of the fish-commission in 

 1871 ; since which time other explorers, both 

 European and American, have employed them 

 to a slight extent in the same way. It has 

 been the experience of this commission, that 

 the combination of tangles with the dredge or 

 trawl is, to say the least, cumbersome ; and, 

 following in the wake of either, they generally 

 pick up only the more or less mutilated speci- 

 mens which have been injured by the iron 

 scrapers or the lead line. By attaching them 

 at the sides, however, as is sometimes done, 

 the latter objection is removed. 



The true province of the tangles is a very 

 rocky bottom, where neither the dredge nor 



