SURVEYING THE ROUTE. 17 



It is recommended that the friction brake should be adjusted 

 io almost counteract the weight of the sinker. The moment of 

 striking bottom can be detected by the hand placed on the 

 spring bar. 



The strain in winding in must be taken by the measuring 

 wheel. Should the wire be wound on the drum under the 

 strain it would probably collapse ; the wire between the 

 measuring wheel and the drum should be felt, and if too tight 

 the rope must be loosened by lowering the pulley P. 



The wire should be passed through a greasy cloth as it is 

 being guided on to the drum to wipe off the moisture. 



Handles are supplied which fit on the square ends of the 

 shafts, so that the machine may be worked by hand should 

 steam at any time not be available. After a sounding has been 

 taken the drum with the wire should be taken oflf and kept in 

 the oil tank until again required. 



With this apparatus the cable ship "Amber" took 380 

 soundings between Bonny, in the G-ulf of Guinea, and the 

 Cape, only losing 1 per cent, of sounding wire out of a total 

 length run out of over 212 thousand fathoms. These sound- 

 ings were taken over a zigzag course of about 3,400 miles, the 

 direct distance being about 2,700 miles, corresponding to one 

 sounding every 7 miles. 



A simple automatic attachment to a sinker for bringing up 

 specimens of bottoui has been devised by Mr. F. R. Lucas, 

 of the Telegraph Construction and Maintenance Co. (Fig. 13.) 

 The cup-shaped jaws are kept apart during descent by two 

 , fingers mounted on spindles, whose bearings are in the side of 

 the gunmetal cups. The brass stem supporting the jaws 

 screws into a bush in the interior of the lead sinker, as shown, 

 and a stout spiral spring bears down on the top of the jaws. 

 To set for lowering, the cups are opened and the two small 

 fingers inside placed horizontally so that the pointed end of one 

 engages in the recessed end of the other (while doing this one 

 looks after one's own fingers). This maintains the cups apart, 

 as in the illustration, during descent ; bat on striking bottom 

 the force of impact, if on a hard substance, suffices to disengage 

 the fingers, and the cups are brought smartly together by the 

 apring above them, thus cutting into and securing a sample of 

 the sea bed. It is found to be verv certain in action in all 



