Introductory 



The worst of all nets of this kind is that the amount of plankton 

 captured is often very small, and it is only the smaller animals 

 which cannot escape, while larger beasts, endowed with great activity, 

 can avoid the snare ; but as Copepoda form the great bulk of the 

 plankton in deep water, and their distribution in relation to ocean 

 currents is perhaps the most important, these little Crustacea are 

 captured in sufficient quantity by the horizontally-towed net. 



As it may be of interest to some to describe how these operations 

 are conducted on a small sailing-vessel, I give a short description of 

 the disposal of apparatus and method of working on board ship. 



A steam boiler is fixed under deck, and supplies motive power to 

 a capstan amidships, of the type generally employed on the larger 

 fishing vessels. 



In series with this is a strongly-made winch, specially designed for 

 the purpose by Messrs. Bullivant and Co., which carries two drums, 

 one for 2,000 fathoms of wire for the closing-net and water-bottle, 

 etc., the other a smaller reel containing fine sounding-wire. The winch 

 is fitted with clutch and brake. 



Thewire used is of seven strands, galvanizedjlZgauge/OSG" diameter, 

 each taking 520 pounds of strain, so that the total breaking strain is 

 about 2,800 pounds. There is a good deal of difference in wire, which 

 requires to be of the very best manufacture. In a wire of less perfect 

 make, which we once had from Birmingham, the strands overrode 

 the central core, so that the wire was from the first useless, the 

 messenger refusing to descend beyond the obstruction caused by the 

 overriding of the wire. 



In 1904 we used a wire of lfi gauge, also of seven strands, 2,000 

 fathoms, weighing 7 cwt., and with a diameter of "064", and breaking 

 strain of nearly 4,000 pounds ; but although on one occasion in very 

 deep water we nearly lost the heavy closing-net through the breaking 

 of all the strands except one, caused by the riding up and down in an 

 exceptionally heavy sea, the lighter wire is sufficiently strong for 

 ordinary purposes. The fact is that heavy closing-nets should not be 

 used in a heavy sea-way. The risk is great, and the results obtained 



