112 Whitehead — Magnetic Effect of Electric Displaeement. 



In principle, the method is to subject a piece of dielectric to 

 an alternating electric field and also to an alternating magnetic 

 field, the directions of the two being at right angles in space ; 

 to adjust the phases of the two to give the maximum effect of 



the displacement current reaction against tlie magnetic field, 

 and to look for motion of the dielectric in a direction perpen- 

 dicular to the plane including the directions of the electric and 

 magnetic fields. In this form the idea was suggested to the 



