410 Intelligence and Miscellaneous Articles. 



observations on the deflections in the electrodynamometer, under 

 the influence of one or the other induction-spiral, it is possible to 

 deduce the relative magnitudes of the magnetic moments of the 

 iron tubes during the continuously interrupted magnetization, and 

 in this way to compare the heat produced with the magnetism 

 developed in the tubes. 



The result of numerous experiments was that there was no heat- 

 ing of the copper tubes, as must have been the case if the heating 

 observed in the iron had been due to an excitation of induction- 

 currents in iron. "With iron which had been exposed to repeated 

 magnetizations, the heat developed changes proportionally with the 

 number of breaks in the second, and increases almost proportionally 

 (though slower) than the increase of the temporary magnetism. In 

 tubes of the same thickness of sides and the same dimensions, but 

 not slit lengthwise, the heat developed is 1*5 times as great as in 

 tubes which are slit lengthwise. 



Tubes of hard metal likewise become heated, according to a law 

 analogous to the laws of the development of heat in iron. Tubes 

 of antimony which were subject to a discontinuous magnetization 

 showed also traces of a rise of temperature. 



At the end of the article the author favours the hypothesis of 

 vortical motion in order to explain the phenomena of magnetization. 

 In his opinion the phenomena observed in discontinuous magneti- 

 zation are a result of the vortical motion of the aether, and of the 

 material of the body in question. — Beibldtter cler Physik, vol. vii. 

 p. 721. 



MINOR ACOUSTICAL EXPERIMENTS. BY PROF. F. FUCHS. 



I. In order to observe the resonance notes of the mouth which 

 determine the vowel sounds, by Helmholtz's methods, a whole 

 series of tuning-forks is necessary, which are not in general at the 

 disposal of teachers and private persons. Hence it may not be out 

 of place to communicate the following method for this purpose, 

 which may be made with any musical instrument of sufficient 

 range. A small india-rubber tube is provided at one end with a 

 terminal of glass or horn for inserting in the ear, while the other 

 end is placed in the mouth. The other ear is closed by a wetted 

 piece of tissue-paper, if it is not preferred to observe the resonance 

 tone in both ears by a branch-tube. The mouth is then given the 

 configuration corresponding to the vowel A, and the various keys 

 of a piano in good tune are struck, beginning with the highest 

 notes of the scale. 



The cavity of the mouth acts then as a resonator put against the 

 ear. If in coming from the higher to the lower notes we strike a 

 string which accords with the special note of the mouth, or is suffi- 

 ciently near it, this, strengthened by resonance, stands out against 

 thejrest of the mass of sound. Proceeding, then, further in the 

 scale, the strengthening proceeds successively for the higher partials 

 of the strings in the order of their rank. The observation is faci- 



