98 M. G. Wiedemann on Torsion. 



of temperature or slight shakings, already contain directly like- 

 wise another proposition, which F. Kohlrausch (1876)* de- 

 duced from the interesting temporal course of the torsion of 

 a wire repeatedly turned in opposite directions. According 

 to this proposition, u Different arrangements (of the molecules) 

 may coexist with one and the same configuration ; and there 

 are forces of elasticity which can temporarily remove the 

 shape of a body from the state of equilibrium/' Here even 

 different positions of equilibrium of the molecules come in, 

 which are at once manifested by the magnetic behaviour, and 

 out of which the molecules may be brought, by various causes 

 and in the course of time, into more stable positions. 



From all the foregoing experiments and many similar ones, 

 the investigation of the magnetism of deformed bodies appears 

 especially suitable for the purpose of gaining intelligence re- 

 specting the molecular processes within them, a knowledge 

 of which it is absolutely necessary to presuppose for a com- 

 plete theory of deformations. Only therein a complication 

 presents itself, inasmuch as with the purely mechanical re- 

 lations the reciprocal magnetic actions of the molecules are 

 secondarily combined. Apart from this, a force acting from 

 without upon a magnetizable body can in this relation be con- 

 ceived precisely like any other mechanically acting force, 

 except only that it moves the molecules in other paths. 



16. Agitation-Effect. — I have now shown, inter alia, that 

 the temporary torsion (or bending) of a body is augmented 

 by slight shakings as well as by magnetizing (i. e. by the 

 motion of the molecules in essentially different paths, as in 

 the first deformation), and likewise by changes of tempera- 

 ture, and the permanent torsion (or bending) diminished, and 

 that in like manner the first slight alterations of figure, 

 shakings, and heatings act upon both the temporary and 

 the permanent magnetism. These actions have not directly 

 any component coinciding with the original direction of dis- 

 placement of the molecules, and are at first independent of 

 the direction of the force that produces the first deformation. 

 I had, on that account, designated the action of this influence 

 as " agitation-effect," by which the molecules become movable, 

 and, more and more in correspondence with the forces acting 

 from without, place themselves in new positions of equili- 

 brium. I had separated this agitation- effect from the regular 

 deformations which indeed go on together with it, but do not 

 emerge undisturbed by it until after its close |. 



* Pogg. Ann. clviii. p. 375 (1876). 



t Streintz lias since (in 1874) analogously designated by the name 

 u accommodation " that property of wires in consequence of which their 



