1884.] resistance between two neighbouring points on a conductor. 135 



copper wire, c is a resistance box of 1 — 200 ohms. The switch 

 keys connected with the galvanometer terminals enable us to 

 change the galvanometer circuit from ABG to PQG with as little 

 delay as possible. 



The readings which were taken are given in the following 

 table. The 1st column gives the resistance in the box c : the 2nd 

 column gives the deflection of galvanometer to the left when the 

 circuit P, Q, G is completed, and the 3rd column the corresponding 

 deflection to the right when the current is reversed. The 5th and 

 6th columns give the readings in similar order when the circuit 

 ABG is completed. To eliminate the slight variations in the 

 electromotive force of the battery the order of observations adopted 

 in any row was that recorded in 2nd, 5th, 3rd, 6th columns, or 5th, 

 2nd, 3rd, 6th columns : this made the total deflections correspond 

 as nearly as possible to the same instant of time. 



