TENSION IN THE ARCH. 



175 



fleeted. On the other hand, in two different paths of 

 conduction there must always be points at which the 

 tension is the same. For in each path the tension 

 begins at a certain positive value (at A), and passes 

 through a value = to a certain negative value (at B). 

 The needle of the multiplier must, therefore, remain at 

 rest if the two ends of the wire of the multiplier are 



Fig. 43. Paths of ellctkicity ix a conductor. 



applied, not to two points of different tension, but to 

 two points of equal tension. This enables us to ob- 

 serve whether in any body in w^hich electric currents 

 move in any form, two points have similar or dissimilar 

 tension, and by systematic experiments of this kind we 

 shall evidently gradually obtain an insight into the 

 form and relative position of the paths of conduction 

 within the body examined. 



