164 



SUBMAKINE CABLE LAYING AND KEPAIRING. 



small damping. The mirror magnets are very small, and the 

 resistance of the coils high, so that there is very little induced 

 current due to the motion of the magnets to produce damping, 

 and the suspension swings round with the ship notwithstanding 

 the soft iron shield. Further, the instrument is quite unsuited. 

 for the measurement of momentary currents, such as electrostatic 

 discharges, owing solely to the absence of inertia in the sus- 

 pended magnets ; but such measurements are seldom required 

 on board. 



Countersink 



for 



Mirror. 



I Magnet. 



Side Elevation of 

 Damper. 



Front, showing Mirror. 



Back, showing Magnet. 



Fig. 81a. — Weatherall and Clark's Damping Suspension for Marine 

 Galvanometers. 



Messrs. Weatherall and Clark, of the Telegraph Construction 

 and Maintenance Company, have devised an improved damping 

 arrangement to this galvanometer, which gives exceedingly 

 good deadbeatness. The arrangement is contained in the 

 ordinary suspension frame, and is therefore applicable to the 

 present form of instrument. 



The damping is effected by an aluminium strip shaded as in 

 Fig. 8lA on which is mounted the mirror and magnet, the usual 



