372 POPULAR LECTURES AND ADDRESSES. 



APPENJDIX B. 



DESCRIPTION OF THE SOUNDING MACHINE. 



IT consists of a wire drum mounted on a 

 galvanised iron frame, and a box to keep it in 

 when out of use. The drawing Fig. 46 shows the 

 machine with the frame carrying the wire drum 

 lifted out of a box and resting on the supports 

 in the position for taking a cast. 



The wire is coiled on a V-shaped 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 machine has been lifted and 

 placed in the position shown in the drawing, the 

 handles should be shipped and fixed by tightening 

 up the thumb screw F. The arm C should then 

 be turned round till it is behind the upright of the 

 frame, and the catch D turned over to prevent the 

 arm C turning. To put on the brake, turn the 

 handle in the direction for winding in the wire ; 

 to take off the brake and allow the wire to run out, 

 turn the handle in the direction for paying out the 

 wire. Half a turn, or at most one turn, of the 

 handle in the direction for paying out is sufficient 

 to release the wire drum and allow the wire to run 

 out with the weight of the sinker hanging on the 

 wire. While the wire is running out the handle 



