508 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



here described, but only in one detail, viz., two ropes 

 with knots are present in place of the two wires. It will be 

 seen that the net can be supported in two ways — (jt) by the 

 lids; (b) by the three cords attached to the upper brass 

 ring of the net. The first is the condition when the net is 

 descending and whilst it is being pulled up through the 

 region which is to be fished. The second is the condition 

 when the net has been closed by a heavy weight run down 

 the rope, which falls upon the closing apparatus and 

 releases the two lids. In this condition it can be hauled 

 up to the surface without any water entering. I have 

 seen this closing apparatus used down to depths of 200 

 fathoms, and it has worked satisfactorily, though it 

 should always be watched in case anything catches and 

 the lids do not close at the proper time. 



It will be seen that the net when lowered is open. 

 This is the case for the ordinary net also, but since the 

 water only enters the net through the filtering tissue, the 

 various organisms will remain outside. It is only when 

 the water enters the net through the mouth that it will 

 make any catch. 



Method of Using the Quantitative Net. 



The wire or rope supporting the net should not run 

 directly from the winch over fixed pulleys to the net, but 

 should pass over a pulley which is supported by an 

 " accumulator." This is particularly important when 

 using the large net in a rough sea, or when the boat is 

 rolling considerably, since, otherwise, the sudden pull 

 as the side of the boat rises to a wave is liable to damage 

 the net, besides rendering the results inexact, owing to 

 the pressure constantly varying. It is essential that the 

 net should be pulled up with an equal speed, and therefore 

 pressure, and the accumulator aids this considerably. 



