Proceedings of the American Academy of Arts and Sciences. 

 Vol. XLVI. No. 20. —April, 1911. 



CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL 

 LABORATORY, HARVARD UNIVERSITY. 



THE EFFECTS OF SUDDEN CHANGES IN THE INDUC- 

 TANCES OF ELECTRIC CIRCUITS AS ILLUSTRATIVE 

 OF THE ABSENCE OF MAGNETIC LAG AND OF 

 THE VON WALTENHOFEN PHENOMENON IN FINELY 

 DIVIDED CORES. CERTAIN MECHANICAL ANAL- 

 OGIES OF THE ELECTRICAL PROBLEMS. 



By B. Osgood Peircb. 



With a Plate. 



