[53] FISHERIES OF THE UNITED STATES. 565 



the roping (lead line) forward and making it fast to the runners at each 

 end of the front beam. The roping was given a longer bight to trail 

 on the ground, and the upper bight was prevented from falling and 

 closing the mouth by netting stretched between the beams. When 

 using the double trawl in deep water, it is customary to weight the 

 runners and the hinder end of the net. 



For rapid trawling in pursuit of fish and Crustacea, Prof. Alexander 

 Agassiz recommends a slight modification of the above trawl, in which 

 the runners are 18 inches high in front and 24 inches high behind. 

 The iron of which they are made is only 2 inches broad, but otherwise 

 the dimensions of the entire trawl are about the same as already given. 



Tangle-Frame and Swabs for collecting marine animals having a spiny 

 or otherwise roughened exterior, or bushy growths, especially on 

 rocky bottoms where they cannot be reached by the dredge. 



United States Fish Commission. 



The old style of tangles, which consisted of several hempen swabs 

 attached to a cross-bar at the hinder end of the dredge, has never been 

 used by the United States Fish Commission, although frequently em- 

 ployed by the United States Coast Survey. The tangles, as a separate 

 instrument, were devised by Prof. A. E. Verrill for the Fish Commission, 

 in 1871, and in the same form, somewhat modified, have been in use ever 

 since. The original set of tangles was constructed of three flat iron 

 bars forming a triangle, the dredge or drag-rope being fastened at one 

 of the angles, and the opposite bar having attached to it several small 

 iron chairs, each about 15 feet long and bearing bunches of unraveled 

 hemp rope at intervals of about 3 feet. Since then the triangular 

 frame-work has been dispensed with, and the cross-bar or chain-bar is 

 supported on two immovable wheels, one at each end, as shown in the 

 sample exhibited. "The wheels are not intended to revolve, but to 

 serve merely as runners and supports for the iron bar, in order to keep 

 it off the bottom and diminish the chances of its getting caught among 

 the rocks, as well as to keep it from breaking and destroying the speci- 

 mens before the tangles themselves can touch them. An oval or ellip- 

 tical form for these runners would answer the same purpose, but the 

 circular form was adopted as the simplest and, perhaps, the least lia- 

 ble to become caught among the rocks." Following are the dimensions 

 of the tangles now used by the Fish Commission: The chain-bar meas- 

 ures about 4 feet in length, and is made of one-half inch iron, 2 inches 

 broad. The wheels are 12 inches in diameter, 2 inches broad, and one- 

 fourth of an inch thick. The cross-piece to the wheels is of the same 

 size iron as the chain-bar. The chains are 15 feet long, of one-fourth-inch 

 iron, and the tangle bunches are about 2 feet long each. It may be 

 advisable to increase the size of the iron for use from large vessels. 



