276 W. E. AND F. B. COOKE. 



rests against the magnets, but when the current is broken 

 it acts as a pendulum, swinging away and forming contact 

 at c for a period that is determined by the position of the 

 weight W. This arrangement has been in use for another 

 purpose at the Sydney Observatory for several months and 

 works very satisfactorily. 



