MISCELLANEOUS NOTES. 581 



net attached to about the middle of the inner side of the outer net, with 

 its rather small open mouth hanging freely about two foet from the bottom 

 of the outer net. The iron framework for the support of the net consists 

 of two stout and broad U-shaped pieces of iron, held rigidly apart at a dis- 

 tance of ten to twelve feet by a very strong iron bar passing between the 

 curved part of the U's, To the extremities of this bar ropes are attached 5 

 these unite in an eye to which the wira rope for trawling is shackled. The 

 mouth of the trawling net is firmly bound to a light chain, which in turn is 

 strongly tied to the extremities of the limbs of the U pieces. Round 

 the margin of the bag-net passes a stout rope to which the net is fixed on 

 one side, and at intervals on the other side, hemp swabs. The end of the 

 bag-net is tied up, made fast to this rope, and weighted with a couple of 

 iron sinkers. The trawling rope is a wire rope, thin and flexilile, but very 

 strong, and is kept coiled on a heavy iron drum bedded in the lower par 

 of the ship aft. From this the wire passes, when in use, up a hatch way, 

 through a series of blocks to the fore-part of the ship where it makes several 

 turns round the drum of a winch, passes through the hawse-hole, through 

 a block attached near the bowsprit end, and so to the trawl. Alongside the 

 bowsprit is suspended a strong spring consisting of a series of rubber discs 

 in an iron framework, so arranged that when the ends of the framework 

 are separated the rubber discs become compressed. One end of this spring 

 is firmly fixed to the bows of the ship, while to the other is attached the 

 last block through which the trawling wire passes. Consequently, any strain 

 put on this wire is at once indicated on the spring by the compression of the 

 rubber discs. 



Before trawling, the positions, depth, and character of the bottom have to 

 be ascertained. The first is obtained by the customary sea methods, the last 

 two by the deep-sea sounding apparatus, the one commonly used consisting 

 of a hollow iron tube furnished inside at its lower end with a pair of butter- 

 fly valves, opening up wards and suspended from a galvanized iron piano wire. 

 This wire is kept coiled on a drum fixed on the fo'castle, and, when running 

 (ut, passes over a second drum, the circumference and number of revolutions 

 of which are accurately known, and recorded on a dial. To cause the sound- 

 ing tube to sink in deep water a couple of iron weights, with cylindrical holes 

 bored in the centre for the tube to pass through, are suspended near the 

 bottom of the tube by a wire loop passing over a tumbling apparatus above 

 the tube. Immediately on striking the bottom the tumbling apparatus, only 

 kept in position -by the weight of the sinkers, is released and liberates the 

 sinkers which are left on the bottom when the sounding tube is 

 reeled in. The velocity with which the tube descends causes it to 

 sink into the mud or sand of the bottom, which rises up and partly fills the 

 tube. On its withdrawal from the bottom the butterfly valves falling back 

 close the tube, and retain the contents for examination and record on the 



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