o>-V DEEP-SEA SOUNDING. 363 



topic to which I may refer, in conclusion, 

 and that is the sound continually produced 

 by the wire. All the time we are employing 

 pianoforte wire in this way we have " sounding " 

 in a double sense. During the whole process 

 of sounding we are continually reminded of 

 the original purpose of pianoforte wire by the 

 sounds it gives out. A person of a musical 

 ear can tell within a few pounds what pull 

 is on the wire by the note it sounds in the 

 length between the castor-pulley at the stern 

 and the haul-in drum which is about five 

 feet inboard of it. 



There are two methods of guarding against rust 

 of the wire. The Americans used oil submerging 

 the wheel in oil when it was out of use. Com- 

 mander Belknap having carried out the process of 

 wire-sounding with remarkable success, I suppose 

 that the Americans are satisfied with the pre- 

 serving power of the oil thus used. On board 

 the Hooper the deep-sea sounding-wire was pre- 

 served by caustic soda when out of use. That 

 substance, when bought wholesale, was so inex- 



