15 .-(3N THE APPLIANCES FOR COLLECTING PELAGIC ORGANISMS, WITH 
SPECIAL REFERENCE TO THOSE EMPLOYED BY THE 
UNITED STATES FISH COMMISSION. 
By commander Z. L. TANNER, U. S. NAVY. 
THE SURFACE TOW NET. 
The tow net for collecting minute animal and jilant forms from tbe surface of the 
sea was among the first devices of the naturalist, and the same apparatus has been 
used at intermediate depths. The range was formerly confined within narrow limits, 
generally not exceeding a few fathoms, and even then it was not altogether satisfac- 
tory, as specimens would naturally find their way into the net while it was being 
hauled to the surface, the exact depth of their habitat remaining a mystery. 
The rings of surface nets in common use by the Fish Commission are of one- 
fourth inch brass or iron wire, from 12 to 18 inches in diameter; the nets are generally 
of silk gauze, although they may be made of cheese cloth or other suitable material. 
The usual practice is to tow them with a small line either astern or over the side while 
the vessel moves slowly through the Avater. Another method has been practiced suc- 
cessfully on board the A for ten years, which, in combination with a submarine 
electric light, has added many new species to our collections. 
A ring, slightly heavier than ordinarily used with a surface net, has a shank which 
is inserted into a stafit, nsuaily a bamboo pole of sufficient length. The net is of silk 
bolting cloth. This device may be used at any time when the vessel is lying without 
headway, or moving very slowly through the water. Its greatest achievements have 
been in connection Avith the electric light. At night, preferably from one to three 
hours after dark, the vessel lying broadside to the Avind and Avithout headway, an 
ordinary Edison 50-candle incandescent lamp, attachetl to ai properly insulated cable, 
is lowered from the lee gangway, 0 feet or more from the ship’s side, just sufficiently 
to keep it submerged Avith the ordinary motions of the vessel. Slow-moving forms 
which are floating on the surface, collect in large nnuibers at the water line as the 
vessel sags slowly to leeward, and more active siAecies gather to feed upon them; as 
soon as the light is lowered, the latter gather around it, as moths about a candle, 
sometimes in great swarms, and it is then that the net reaps its richest harvests. 
Surface collecting hasahvays been a marked feature in the work of tire Albatross, 
and improved methods were sought from the first. The opi)ortuuities for this line of 
investigation, Avithout iuterfering with other work, were unprecedented, as the net 
above described could be used Avhenever the vessel was hove-to for sounding, etc., and 
<the toAV net A\ms available from the time the traAvl was put over the rail until it was on 
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