/ 



fe'/ 



JoLY — On the Investigation of the Deep-sea Deposits. 267 



away from the float (fig. 2), it being assumed that the winding machinery 

 is forward in the boat. This manoeuvre results in pulling the lifting wire 

 over the sheave, and, of course, in correspondingly raising the sounder. The 

 sea anchor only slowly drifts in the direction taken by the boat. When tlie 

 boat has run back about one or two hundred fathoms, she is brought to rest, 

 and her motion reversed. The lifting wire is now gripped by the nipper, 

 which seizes it just below the pulley: it cannot, therefore, run back again 

 over the sheave. The wire is taken in on the boat as the boat approaches the 



buoy. It may for safety be kept stretched by a weight running on a block 

 and sheave sent out from the boat, and left upon the wire, throughout the 

 whole of the operations. This operation is repeated till the soimder is brought 

 to the surface. 



The advantages of this mode of raising the sounder are many. There 

 can be no sudden stress put on the wire due to heaving of the boat, and the 

 heaving of the float is mitigated by its ready submergence. The speed of 

 raising the sounder may be very considerable without risk either to winding- 

 engines or to lifting wire. The float acts as a spring, absorbing excessive 

 stresses, and revealing them by its submergence. The wire, finally, is 

 brought on to the winding-drum in a state of low tension, and all danger of 

 bursting the drum is avoided. 



SCIENT. PKOC, R.D.S., VOL. XIV., NO. XYIII, 



2u 



