464 Prof. W. Beetz on the Molecular Changes 



least, is very improbable. On the hypothesis of moveable par- 

 ticles, however, this difficulty entirely disappears, since the very 

 natural supposition, that the particles of the magnet are at un- 

 equal distances from each other, completely explains the observed 

 differences between different magnets. From the same supposi- 

 tion it follows, moreover, that there never can be a magnet com- 

 pletely saturated with temporary magnetism. The most power- 

 ful magnetizing currents will never be able to bring the axes of 

 the particles into perfect parallelism with each other. The posi- 

 tion of the axis of each particle will depend on the resultant of 

 the force of the current and the forces exerted on it by the 

 neighbouring molecular magnets ; so that, as the strength of the 

 current increases, the temporary magnetism approaches asympto- 

 tically to a limit. It is sufficient to refer to W. Weber's* re- 



searches on the magnitude of the ratio — and the accompanying 



graphic delineation of his results, to be convinced of the truth 

 of this fact. 



Additional vouchers for the truth of the hypothesis of rotatory 

 particles are furnished by the phsenomena which accompany the 

 reversal of the poles of a magnet. From a series of experiments 

 in which a hard steel bar is magnetized by rubbing it with a 

 magnet first in one direction and then in the other, Suchelett 

 came to the conclusion, that the primary magnetism is the 

 strongest; that by reversing the poles the magnetic power is 

 diminished, and, moreover, that it continues to diminish for 

 every subsequent change that may be made, but only to a fixed 

 limit. Moser J, in communicating these experiments, adds the 

 remark, " It is very natural that the reversal of the original 

 polarity of a magnet should weaken its intensity, as in fact it is 

 known to do, since, owing to the coercive power of the bar, a 

 residuum of its original polarity is always left behind ; but that 

 the same diminution of intensity should accompany subsequent 

 reversals of polarity does not admit of the same explanation, and 

 is therefore, at first sight, very remarkable." 



To this observation, which relates only to the permanent 

 magnetism of a steel bar, may be added another, which is just 

 as little explicable on the hypothesis of magnetism consisting of 

 a separation of magnetic fluids. Wiedemann § found that a steel 

 bar, magnetized by means of a current of intensity I, and after- 

 wards unmagnetized by a weaker current of intensity — I, can- 

 not be further magnetized in the opposite direction by the latter 

 current. Now the hypothesis of the separation of magnetic fluids 

 * Op. cit. p. 569 et seq. 



t Ann. de Chimie et de Physique, vol. liii. p. 248. 

 £ X Dove's Repertorium der Physik, vol. ii. p. 140. § Op. cit. p. 173. 



