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LI. Change of the Modulus of Elasticity oj Ferromagnetic 

 Substances by Magnetization. By K. Honda, Rigakushi, 

 S. Shbiizu, Rigakushi, and S. Kusakabe, Rigakushi *. 



TT has been generally admitted that magnetization 

 has very little effect upon the elasticity of ferro- 

 magnetic substances. Wertheim f first measured with a 

 micrometer the elongation of an iron wire due to tension in 

 the magnetized and in the unmagnetized state with exactly 

 the same result. Griiillemin + placed an iron bar horizontally 

 and fixed it at one end and hung a small weight at the other, 

 which was left free. The magnetization of the bar by a 

 coaxial coil produced a small rise of the weight. Wartmann § 

 used Chladni's figures to investigate the change of elasticity 

 of magnetized iron and steel plates, and also examined the 

 sound accompanying longitudinal and transversal vibrations 

 of magnetized iron wires. Xo influence of magnetization 

 was observed. Treves || set in vibration two tuning-forks 

 having the same period of vibrations. When one of them 

 was placed in a coil and magnetized by a strong electric 

 current, its vibration was accelerated producing beats ; but 

 when the current was broken the beats were no more to be 

 heard, and the two notes were in unison. This experiment 

 shows an increase of the modulus of elasticity by mag- 

 netization. H. TomlinsonH found, on the contrary, that the 

 elongation of an iron wire by loading is independent of 

 magnetization. Bock** found the effect to be smaller than 

 ^ per cent., if there is any. By passing an electric current 

 through a stretched piano forte- wire, M. G. Noyesjt noticed 

 an increase of elasticity, which was less than 1 per cent. 

 Maurain %% also found a small increase of elasticity by means 

 of tuning-forks placed in a very strong magnetic field. In the 

 investigation on the effect of tension upon magnetic elongation 

 of a pianoforte- wire, B. Brackett§§ observed a small increase 



* Communicated by Prof. Xagaoka, 



t "Wertheim, Ann. de Chim. et de Phys. [3] xii. p. 610 (1842). 



% Guillemin, Comp. Rend. xxii. pp. 246, 432 (1846). 



§ "Wartmann, Ann. de Chim. et de Phys. xxiv. p. 360 (1848). 



l| Treves, Comp. Rend lxvii. p. 321 (1868) ; Archives des Set. Nat. n. s. 

 xxxiii. p. 74 (1868). 



H Tomlinson, Proc. Rov. Soc. xl. p. 447 (1886). 



** Bock, Wied. Ann. liv. p. 442 ^1895) ; Phil. Mag. [5] xxxix. p. 548 

 (1895). 



ft M. G. Noves, Phys. Rev, [4] ii. p. 277 (1895); Phys. Rev. [6] iii. 

 p. 432 (1896). 



XX Maurain, Comp. Rend. exxi. p. 248 (1895). 



§§ B. Brackett, Phys. Rev. [5] v. p. 257 (1897). 



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