THE LAYING OF SUBMARINE CABLES. 



16a 



small controlling magnets, by means of which the spot of light 

 can be brought to zero. 



This instrument is at its best in bridge balances and other 

 tests involving a simple balance to zero. It also does fairly well 



Fig. 80. — The Kelvin Marine Galvanometer. 



Fig. 81.— Suspension Frame. 



for false zero work, but in its original form it requires practice- 

 to read a deflection instantly, as the spot oscillates for some 

 time before coming to rest. This is chiefly due to the very 



m2 



