52 POPULAR LECTURES AND ADDRESSES. 



attached, although I have not yet tested it with 

 this adjunct. With or without the Massey fly it 

 can be hauled in quite easily by two men, though 

 the ship is going at a speed of twelve knots. The 

 whole watch in a large steamer is habitually em- 

 ployed in hauling in the ordinary deep-sea lead, 

 when soundings are taken with the ship going at 

 full speed. 



[37. ADDITION OF AUGUST 4, 1887. The 

 machine referred to in the preceding paragraph 

 has, since this lecture was delivered, been developed 

 and become a practical and useful aid to naviga- 

 tion. The diagram (Fig. 10) shows the machine 

 in the position for taking a cast. The steel wire 

 is coiled on a V' sria P e d ring, A. This ring A can 

 revolve independently of the spindle, or it may be 

 clamped to the spindle by means of the plate BB. 

 When the ring A is undamped from the spindle 

 the sinker descends and the wire runs out. As 

 soon as the sinker touches the bottom the wire 

 slacks. The ring is then clamped to the spindle, 

 which prevents any more wire running out, and 

 winding in commences. The sinker is a hollow 



