448 Stress and Strain and the Properties of Matter. [May 27, 



tion, provided the magnetising current be, previously to experiment- 

 ing, reversed a great number of times. When no previous reversals 

 have been made the internal friction is slightly increased by intense 

 magnetisation. 



2. When the deformations produced by the oscillations are large 

 the internal friction is very sensibly increased by sustained longi- 

 tudinal magnetisation of large amount. 



3. The torsional elasticity is entirely independent of any sustained 

 longitudinally magnetising stress which may be acting upon an iron 

 or steel wire, provided the deformations produced by the torsional 

 oscillations be small. When the deformations are large, the number 

 of oscillations executed in a given time is very slightly lessened by 

 sustained longitudinal magnetisation of large amount. 



4. When the magnetising current is interrupted and, to a greater 

 extent, when it is reversed repeatedly whilst the wire is oscillating, 

 the internal friction is increased, provided the magnetising stress be 

 of moderate amount. The increase of internal friction may become 

 very considerable when the magnetising stress is great. 



When the number of interruptions or reversals in a given time of 

 the magnetising current exceeds a certain limit the effect on the 

 internal friction begins to decline. 



5. When the deformations produced by the oscillations are small, 

 the torsional elasticity is not affected by either repeatedly interrupted 

 or reversed longitudinal magnetisation even when the magnetising 

 stress is large. 



6. There exists a limit of magnetic stress within which no per- 

 manent rotation whatever of the molecules is produced. This limit 

 may be widened by previous repeated reversals of a large magnetising 

 stress. 



7. The passage of a moderate electric current, whether sustained or 

 interrupted, through a torsionally vibrating wire of iron, steel, or 

 nickel does not affect, except by heating, "either the internal friction 

 or the torsional elasticity, provided the deformations produced by the 

 oscillations be small. 



8. The effect of longitudinal magnetisation, even when carried to 

 the point of saturation, on the longitudinal oscillation of an iron or 

 steel wire, is nil. 



9. The passage of an electric current, whether sustained or inter- 

 rupted, through a longitudinally oscillating wire of iron or steel does 

 not, except by heating, affect the number of oscillations executed in a 

 given time. 



10. When the deformations produced by the oscillations do not 

 exceed a certain limit, the internal friction cannot apparently depend 

 upon the permanent rotation of the molecules about their axes. 

 When, however, the deformations exceed this limit, the internal 



