NARRATIVE OF THE CRUISE. 



75 



The Tread (see fig. 20) was of the ordinary pattern, consisting of a beam of wood 

 with an iron at each end, to which a large V-shaped net was attached, so that its mouth 

 was kept spread open by the trawl irons and beam. The size of the net depended on 

 the length of the trawl-beams, which were 17, 13, and 10 feet in length; the smallest 

 being used for very deep water and the others for lesser depths. On the trawl- irons and 

 bag of the net were hung 28 lb. leads, so as to 

 keep the net down to the bottom when trailing 

 alon^. At first, beams made of fir were used 1 

 for trawling in deep water, but were replaced 

 by oak or teak beams, as the fir spars came up 

 broken, and so much compressed from the pres- / 

 sure of the water that the knots in the wood stood 

 out three quarters of an inch above the surface 

 of the spar. The bottom of the netting was, as 

 in the case of the dredge, usually lined with 

 bread-bag stuff, to prevent the smaller animals 

 being washed out whilst being hove up through 

 the watery It is, however, preferable in place 

 of this bread-bag stuff, to use a small strip of 

 fine linen or cotton for the netting of both the 

 trawl and dredge, and to change it at each 

 haul. Improvements, both in the form and the 

 method of using the dredge and trawl, have 

 recently been suggested by Captain Sigsbee, 1 by 

 the naturalists of the Norwegian North Atlantic 

 Expedition, 2 and others. 



The Sieves. — Close to the place where the 

 dredge was emptied there were always one or two 

 tubs, about two or three feet in diameter and 

 twenty inches deep, each of which was provided 

 with a set of sieves, so arranged that the lowest 

 sieve fitted loosely within the bottom of the tub, 

 and the three succeeding sieves within one another 

 (see fig. 21). Each sieve was provided with a pair of iron handles, through which the 

 hand could pass easily, and those of the largest sieve were made long, so that the whole 

 nest could be lifted without stooping and putting the arms into the water. The upper 

 smallest sieve was usually deeper than the others ; it was made of a strong open net of 



1 Sigsbee, Deep-Sea Sounding and Dredging, Washington, 1880. 



2 C. Wille, Norwegian North Atlantic Expedition, 1876-1878, part iv., The Apparatus and How Used. 



°7 



) 



Fig. 20. — The Beam Trawl used in deep-sea work. 



