( 491 ) 



XVII. — The Superposition of Mechanical Vibrations (Electric Oscillations) upon 

 Magnetisation, and Conversely, in Iron, Steel, and Nickel. By James Russell. 



(MS. received November 23, 1906. Read May 7, 1906. Issued separately February 28, 1907.) 



CONTENTS. 



Objects of Investigation 491 



Apparatus 492 



Effect of the Load 493 



Superposition of Vibrations and Field . . . 495 



Diagrams .... 



Intensity of Vibrations, varied 

 Intensity of Vibrations, constant 



Results under B Conditions. 



Annealed. 



Permeability page 499 



Residual Magnetisation in Relation to Field . „ 500 

 Residual Magnetisation in Relation to In- 

 duction „ 500 



"A oo 



C OS 



p ft 



Coercive Force .... 

 Hysteresis Loss in Relation to Field 

 Hysteresis Loss in Relation to 

 tion 



Indv 



501 

 502 



502 



a ° 

 a © 



c 



be a> 

 cs op 



Q ft 



A Conditions. 



Diagrams 

 Results . 



Annealed, 

 page 502 

 „ 502 



Summary of Results 

 Magnetic Hysteresis 

 Molecular Theory 



PAGE 



509 

 511 

 511 



Metals. 



Quenched, 

 page 504 \ - 



505 I S § 



„ 506 



„ 507 

 „ 508 



„ 508 



Quenched, 

 page 506 

 ,, 508 



Q ft 



a &> 

 a o 



03 iO 



be <u 

 ea bD 



Q ft 



Electric Oscillations 



Conclusion ....... 



Electric Oscillations (Read December 17, 1906) 



PAGE 



. 496 



. 496 



498-508 



PAGE 



513 



514 

 515 



That mechanical vibrations affect magnetisation has long been known. The simple 

 experiment of hammering an iron rod (Gilbert) in the earth's magnetic field needs 

 only to be mentioned 



About twenty years ago Ewing published investigations upon the effects of vibra- 

 tions on magnetism. # These have been summarised in his subsequent work, Magnetic 

 Induction in Iron and other Metals. He states (§ 84, 3rd ed.) that the "influence 

 of vibrations and mechanical disturbances generally" "may be succinctly described by 

 saying that vibration lessens those differences of magnetic condition to which hysteresis 

 gives rise. Thus, if we tap a piece of iron during the application and removal of a 

 magnetising force, we find at each stage of the application that tapping increases the 

 susceptibility, and at each stage of the removal it reduces the retentiveness." 



The effects of vibrations upon magnetism have in general been investigated by 

 tapping. That is to say, vibrations have been superposed upon field (induction). But 

 the effect of vibrations cannot be limited to one method of relative superposition of 



*Phil. Trans., 1885, p. 564. 

 TRANS. ROY. SOC. EDIN., VOL. XLV. PART II. (NO. 17). 69 



