ON DEEP-SEA SOUNDING. 355 



the weight of the wire out. Then, the sinker 

 being 34 Ibs., we have 24 Ibs. weight left for 

 the moving force. That, I have found, is 

 amply sufficient to give a very rapid descent 

 a descent so rapid that in the course of half 

 an hour, or three-quarters of an hour, the bottom 

 will be reached at a depth of 2,000 or 3,000 

 fathoms. The person in charge watches a 

 counter, and for every 250 fathoms (that is 

 every 250 turns of the wheel) he adds such 

 weight to the brake-cord as shall add 3 Ibs. 

 to the force with which the sounding-wheel 

 resists the egress of the wire. That makes 

 1 2 Ibs. added to the brake-resistance for every 

 1,000 fathoms of wire run out. The weight 

 of 1,000 fathoms of the wire in the air is 

 i4Mbs. In water, therefore, the weight is 

 about 1 2 Ibs. ; so that if the weight is added 

 at the rate I have indicated the rule stated 

 will be fulfilled. So it is arranged that when 

 the 34 Ibs. weight reaches the bottom, instead 

 of there being a pull or a moving force, of 

 24 Ibs. on the wire tending to draw it through 



A A 2 



