﻿the Electric Spark is an Electromotor. 51 



Experiment 20. Distance between the iron knobs 0*5 millim. 

 Formation of sparks. 



x—y. 



x+y. 



x—y. 



2205 



202-0 



2205 



2210 



201-8 

 2000 



220-0 



201-3 



Mean of the first two and last two observations . . =220*5. 

 Position of equilibrium when the machine was at rest =243*1. 



From this we obtain 

 a? + y=41-8, x-y = 22'6, x=32% y = 9-6, and- =3-35. 



The electromotive force was thus now equal to that of 33*5 

 Bunsen's elements. If from # = 32*2 we subtract 6*3, it is 

 found that the same force cannot be less than that of 27 elements. 



Experiment 21. The knobs were of tin. Distance 3 millims. 

 Formation of sparks. Position of equilibrium of the magnetic 

 needle =242*5. 



x—y. x+y. x—y. 



169-5 136-0 174-5 



169-5 141-0 173-0 



135-5 



137-5 



Mean of the first two and last two observations = 171 "6. 

 From this we obtain 



# + y = 105-0, x-y = 70'9, a? = 88'0, y=l7'l, and - = 5-15. 



The electromotive force amounts therefore to 51*5 elements. 

 If 6- 3 is subtracted from 88*0, we get as the limiting value for 

 the same force that of 47 "8 elements. 



Experiment 22. The distance between the tin knobs 0*5 millim. 

 Formation of sparks. Position of equilibrium of the magnetic 

 needle =241*5. 



x—y. x+y. x — y. 



225-0 208-0 227-0 



224-0 209-0 226-5 



2100 



Mean . . 2090 



The mean for x — y = 225 -5. 

 From this we obtain 



a? + y = 32-5, x~-y = 16*0, x = 24 i S, y = 8-3, and -=2'93. 



E 2 



