EQUIPMENT. 



friction-line, in order that any undue slacking and consequent 

 kinking of the wire may be avoided. To secure this quick stop- 



Fig. 4. — Sigsbee Sounding- Machine, profile view. (Sigsbee.) 



page, the reel should be made as light as 

 the very considerable strength required 

 for reeling in will permit. In reeling in 

 without the reeling-in or strain pulley, it 

 is necessary that the reel should be of 

 sufficient streno;th to resist the accumu- 

 lated strain of successive convolutions of 

 the wire under strong tension (the difficulty encountered by 

 Thomson in his first sounding). It is rigidly attached to its axle 

 by a key, and the easy removal of the key would be a conve- 

 nience, since the reel, without its axle, could be stowed into a 



