﻿52 Prof. E. Edlund's Experimental Proof that 



Thus the electromotive force = that of 29*3 elements, and its 

 limiting value = that of 21*7 elements. 



Experiment 23. The knobs were of brass. Distance 3 millims. 

 Formation of sparks. Position of equilibrium of the magnetic 

 needle =238-5. 



x-y. 



x+y. 



x—y. 



165-5 



1290 



163-5 



161-0 



135-0 



162-5 



162-0 



128-0 

 137-5 

 128-5 





Mean . . 131*6 



Mean of the first and last observations = 162*9. 

 From this we obtain 



x + y = 10&9, x-y=75-6, #=91'3, y=l r o'7, and- =5-815. 



The electromotive force in this case = that of 58*15 elements, 

 and its limiting value = that of 54*14 elements. 



Experiment 24. The distance of the brass knobs 0*5 millim. 

 Formation of sparks. Position of equilibrium of the magnetic 

 needle 238*7. 



x — y. #+3/- x ~y- 



224*0 206*5 218*0 



223*5 203-0 2190 



209*0 



Mean . . 206*2 



The mean for x—y is 221*1 . 

 From this we get 



x + y = S%-o, x-y = l7-6, # = 25-02, ^=7*45, and -=3-36. 



Consequently the electromotive force =33*6, and its limiting 

 value that of 25*2 Bunsen's elements. 



The electromotive force in the electric spark appears unexpec- 

 tedly great if it is compared with the electric force in the voltaic 

 arc. From a former determination, this, when the poles were of 

 brass, was about equal to that of 15 elements; but in the 

 electric spark, from what has been above said, it amounts to from 

 50 to 60 elements ; and yet the disintegration of the poles with 

 the luminous arc appears to be very much stronger than with 

 the spark. 



Two circumstances must here be taken into account. In the 

 first place, the voltaic arcis continuous and the spark discontinuous. 

 The duration of the spark, as is well known, depends on several 

 circumstances. Under the circumstances of the present experi- 



