﻿50 Prof. E. Edlund's Experimental Proof that 



Position of rest when the currents went in opposite direc- 

 tions : — 



x — y. 



178-0 

 178-0 



The mean of the first two and last two observations is =177"5. 

 From this we get 



^ + 2/=94-0, <z>-?/ = 66-5, ^=80-3, y=13-8, and - = 5-82. 



As the battery consisted of ten elements, the electromotive 

 force of the spark was equal to that of 58*2 Bunsen's elements. 



It must here be at the same time remarked that the deflection 

 x is not exclusively caused by the spark-current, but part de- 

 pends on the electrical discharge of the machine. To obtain at 

 any rate a limiting value for this part the following experiments 

 were made : — 



Experiment 19. The knobs so far apart that no sparks were 

 formed. 



Position of equilibrium when the machine was at rest: — 



231-5 

 231-3 



Position of equilibrium when the machine was at work : — 



225-0 



224-7 



The battery-current was reversed by the commutator : — 



225-0 

 225-0 



Position of equilibrium when the machine was at rest; — 



231-0 

 231-0 



Mean of the first two and last two observations =231*2. 



From this experiment it follows that the battery-current has 

 no influence on the magnitude of the deflection — a natural con- 

 sequence of the circumstance that its circuit is open when no 

 sparks are formed between the knobs / and g. The discharge- 

 current, however, brings a deflection of 6'3 divisions. This de- 

 flection cannot, of course, be so great if sparks are formed between 

 / and g • for part of the discharge passes then through the path 

 of the sparks. That part, therefore, of the deflection x which is 

 caused by the current forming in the spark fg cannot be less 

 than 80-3 — 6-3 = 74-0 divisions. We thus find that the elec- 

 tromotive force of the spark cannot be less than that of 53 '6 

 Bunsen's elements. 



