DESCRIPTION OF A CLOSING SUBMARINE TOW-NET. 281 



brought to a full stop. The net is light and of small mesh, preferably 

 half inch. It is lined with bobbinet or mosquito netting - , with a delicate 

 inner lining of silk bolting-cloth, the last being the real collector, to 

 which the outer nets act as supports. 



In this combination of three nets all are of full width to the bottom, 

 where they are closed by a lashing, the inner nets being secured rather 

 slack, in order to avoid strain upon them in towing. As used on board 

 the Albatross, by steam power at all depths, the net and its appliances 

 have been constructed somewhat heavier and stronger. Additional 

 weight is secured by passing the tripping-arm through a GO-poundshot, 

 of the ordinary pattern used for sounding, the shot being secured by a 

 bolt to prevent its slipping when the arm is capsized. (See pi. 0, fig. 4.) 



A deep-sea tow-net, closed, with the folded jaws protecting its mouth, 

 offers little resistance to the water, and cau be heaved in rapidly 

 without the danger of being torn away from an open and widespread 

 net-ring, while the friction upon the contained organisms is reduced to 

 the minimum. 



The time gained in deep-sea work, with a folding-ring net which will 

 permit of the steam winch reeling in at full speed, and the small stowage 

 space required on shipboard for a net of this pattern, are matters of 

 considerable importance. The readiness with which this net can be 

 carried on deck by one man and attached to the wire dredge rope 

 without complicated adjusting is perhaps the most important point of 

 all in its favor, while its cost is less than that of any intermediate net 

 hitherto employed. 



This device has also been constructed in very light form, with a net 

 ring 18 inches in diameter, for use in lakes or at very moderate depths, 

 the heavier outside net being done away with, leaving merely the mos- 

 quito netting with its lining of silk bolting-cloth. 



In this form it will be useful in gathering the minute life, Crustacea, 

 etc., of the Great Lakes, a knowledge of which is essential in its bearing 

 upon the food of young whitefish and other important fishes now being 

 propagated artificially. 



The folding-ring tow-net is also available for use as an ordinary 

 surface tow-net, without the employment of the messenger and the 

 lead sinker. 



The collections made by the Albatross during the past summer with 

 the intermediate net were from depths of 20 to 200 fathoms, the net 

 being lowered in one instance to 575 fathoms, when it accidentally 

 touched bottom. The forms obtained consisted principally of minute 

 Crustacea, medusa;, annelids, and fishes, which have not yet been studied ; 

 but the ordinary surface tow-net having been used at the same stations 

 as the intermediate net, the contents of the two nets were usually found 

 to differ somewhat in character and quantity. As a rule, the surface 

 net contained a slightly greater quantity of material than the interme- 

 diate net, but at some stations the reverse was the case, while the inter- 



