SURVEYING THE ROUTE. 11 



to balance the weight of wire outboard has long since been 

 discarded. 



The Lucas hand sounding machine is illustrated in Figs. 8 

 and 9. This machine is used principally for depths up to 

 400 fathoms and for flying soundings. The chief point in the 

 design is the automatic application of a brake to the wire 

 drum immediately the sinker strikes bottom. The drum is 

 thus prevented from overrunning and shooting the wire out, 

 forming coils and kinks in it. The wire runs out freely while 

 the weight is sinking (the brake being slack), but the moment 

 l)ottom is reached the motion of the drum is arrested. The 

 wire is contained on the drum or reel A, and when in use is 

 unwound from the underside and taken one complete turn 

 round the wheel E. The spindle of the latter is mounted in 

 a frame B, capable of swivelling about the hollow bearing C, 

 through which the wire passes. 



The frame also carries a revolution counter gearing into a 

 pinion on the spindle. The hollow bearing C, and with it the 

 wheel and frame B and the upright F, are capable of moving 

 in a vertical plane about the centre D, taking up the position 

 shown in full lines when the wire and weight are running 

 out. 



In this position the bar J is moved to the left, and the brake 

 band I round the reel slackened, allowing the wire to run 

 out freely. Immediately the tension on the wire is relieved by 

 the weight touching bottom the spring G pulls the parts 

 F, B and C into the position shown by the dotted lines, causing 

 the bar J to be pulled to the right and the brake to be 

 instantly applied. 



The lever K moves with F, C and B about the centre D, and 

 the pawl which it carries can be engaged in the teeth of the 

 rack to lock the above movable parts in any position. Thus, 

 when putting sinker on to end of line previous to running 

 out, it is convenient to have the brake applied to the machine, 

 which is done by locking the lever K in the position shown by 

 dotted lines. In this machine, which is not used for great 

 depths, the wire is reeled in by hand, 



A modified form of the apparatus is shown in Fig, 9. 

 The wire passes from the large reel, and makes one turn 

 round the suspended wheel, which also carries the indicator 



