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DISCOVERY REPORTS 



Closing Mechanisms for Vertical Nets. The apparatus used during most of the com- 

 mission for the closure of vertical nets is that shown in Fig. i6: in general design it 

 closely resembles that employed by Hjort.^ In our hands this type was found to give 

 a certain amount of trouble: it was liable to release prematurely and sometimes the 

 wire was found to have come out from the slot in the top lever, and by jamming the 



^ 



Fig. 1 6. Closing mechanism for vertical 

 nets: a, mechanism; b, messenger. 



Improved closing mechanism 

 for vertical nets: xi. 



movement to have prevented release altogether. These difficulties were met by in- 

 creasing the strength of the spring and by inserting a cotter pin through the ends of the 

 forked lever to keep the wire in its proper place. With these alterations the apparatus 

 worked well in smooth water, but in bad weather, with the ship rolling, premature 

 releases were still liable to occur. If the wire strayed much from the vertical it would 

 bear on the cotter pin and eventually effect release. During the second year of the 

 commission a different pattern of closing mechanism was made by the engine-room 

 staff and this has been found to be a great improvement on the former model, working 



1 Hjort, Depths of the Ocean, p. 48, fig. 31, London, 1912. 



