V. CLOCKS AND SUNDIALS. 



361 



These consist of 



1st. An ordinary clock, requiring periodical winding, to serve as a normal 

 or motor clock for the system. 



Wires from the reverse poles of two galvanic batteries are connected with 

 slender insulated springs, so placed that the pendulum in vibrating touches 

 each alternately, and so transmits through the pendulum rod reverse currents 

 to the line wire and subsidiary clocks. 



This arrangement may be seen through the glass sides of the clock-case, 

 and in Fig. A. 



2nd. Electro-sympathetic clock. The pendulum consists of a coil of insu- 

 lated copper wire, the ends of which are led up the rod, and are introduced as 

 a loop into the line wire. Within the coil (which forms the ball or bob) a 

 double cluster of magnets, having their similar poles slightly separated in the 

 middle, is fixed to the casing of the clock. The currents from the motor 

 clock passing through the wire coil cause it to be alternately attracted and 



Fig. B. 



