100 ELECTRICAL MEASUREMENTS 



the restoring moment due to the suspension strip. In other 

 words, the instrument is one having a long time of vibration. 

 This is necessary in order that the response to the impulse caused 



FIG. 51. Long-period ballistic galvanometer. 



by the passage of the transient current may be rendered so slug- 

 gish that the entire quantity due to the discharge of the condenser 

 the change of magnetic flux may have time to pass through the 

 SSSl^^^SSE^^^W^ appreciably. In the 



PROPERTY CF ELECTRICAL LABORATORY^ 



FACULTY OF APPLIED SCIENCE. 



