Whitehead — Magnetic Effect of Electric Displacement. 123 



per ampere, thus of the same order of magnitude as in the cal- 

 culation for the first form of the apparatus. The suspension 

 fiber was also the same, and so, therefore, the order of magni- 

 tude of the calculated deflection. 



Position Volts 



Center 7-8 



1 8-1 



2 8-6 



3 9-9 



4 (near coil) 12-1 



Results. — With this apparatus, when the electric Held alone 

 was put on, the beam after a sufiScient time always found a 



5 



SI. 



5 20 



edge 



position of equilibrium, in some places stable and at others 

 unstable. The former seemed to be in a diameter which passed 

 through the hard rubber supporting chairs of the rings, doubt- 

 less owing to a slight concentration into the chairs of the field 

 of force ; a slight departure from this line was sufficient to cause 

 the beam to wander to some other position, and the indications 

 seemed to certif}^ a quite uniform electric field. On putting 

 on the electric and then the magnetic fields, (5 "3 amperes in 

 coil) there was a deflection of from 2°"^ to 3^°^, which, however, 

 did not reverse or show any regular difference in amount 

 when either field was reversed ; it was found that the magnetic 



