JWDEXFT- 



THE 

 LONDON, EDINBURaH, and DUBLIN 



PHILOSOPHICAL MAGAZIiNE 



AND 



JOURNAL OF SCIENCE. 



[SIXTH SERIES.] "^- / 



JULY 1903. 



I. On Electrostriction. By Louis T. Moee, P7uD.^ Professor 

 of Physics in the University of Cincinnati *. *^ '*' 



[Plate I.] 



IN a previous paper f, I published an account o£ some ex- 

 periments made on the supposed elongation o£ a dielectric 

 placed in an electrostatic field. The conclusion reached was 

 that glass and hard rubber do not elongate perpendicularly 

 to the field, and that the effects observed by others were due 

 to different causes. This conclusion was something o£ a 

 disappointment, as I had undertaken the work for the purpose 

 o£ solving a problem based on this effect of electricity. 



The laws of electrostriction had been so elaborately formu- 

 lated, and had been substantiated by so many experimenters, 

 that their results were accepted and an apparatus constructed 

 which would record changes of the given magnitude, allowing 

 for a margin of safety. In the early stages of the work, 

 when the tubes of glass operated on were charged, elongations 

 were observed and recorded in ray notes which agreed fairly 

 with those of my predecessors. But combined with them 

 were, at times, irregularities and discrepancies. The motion 

 of the recording image was jerky, and the return of the tube 

 after discharge sometimes great and at other times small ; 

 occasionally a tube was used which showed practically no 

 deflexion when charged. After considerable difficulty these 



* Communicated by the Author. 



t Phil. Mag. vol. 1. pp. 198-210 (1900). 



Phil Mag. S. 6. Vol. 6. No. 31. July 1903. B 



