Whitehead — Magnetic Effect of Electric Displacement. 113 



writer by Professor Rowland shortly before his death. Some 

 twelve years before he made the same suggestion to Dr. Louis 

 Duncan, who constructed a crude form of apparatus, but 



□ 



B Ti 



h 



d 



S^ 



abandoned the work on account of the difficulty of obtaining 

 a uniform field. 



In each of four modifications of the form of the apparatus 

 embodying the above principle, a block of dielectric was hung 



