466 



Prof. W. Beetz on the Molecular Changes 



wise, though in less degree, with the magnetism in the opposite 

 direction. Neither in the case of the electrolytic magnets, nor 

 in the case of the steel bars, was the magnetism induced by the 

 stream —I ever equal to that induced by the stream +1: the 

 difference between the two kinds of magnets is in this respect 

 only quantitative ; but in the case of electrolytic magnets, the 

 difference between the magnetisms induced by the — m and +m 

 currents is always greater than in the case of steel bars. The 

 former may be compared with steel bars which have been first 

 magnetized by a powerful current, and have been alternately de- 

 magnetized and remagnetized by a weaker one. In divisions 

 7, 8, and 10, there are small deviations from the general course, 

 to which we shall refer hereafter. 



With regard to permanent magnetism, the electrolytic magnets 

 behave quite differently from ordinary steel-bar magnets. If a 

 steel bar is magnetized alternately in one direction and the 

 other, the positive as well as the negative magnetisms continually 

 decrease, so that the two extremes lie between continually 

 narrowing limits, which is exactly what Wiedemann found to be 

 the case with respect to the magnetic maxima and minima of a 

 steel bar which had been magnetized by a current I, and de- 

 magnetized by a lesser current —I. 



If the magnetizing currents are weak, the positive values re- 

 main always much greater than the negative ; the stronger the 

 currents the more nearly the positive and negative values ap- 

 proximate to each other ; and in the case of currents which are 

 capable of almost completely saturating the bar, each positive 

 value lies between two negatives. This is shown in the following 

 Table :— 



On the other hand, the negative magnetism of electrolytic 

 magnets is always less than the positive, even when they are 

 subjected to the influence of the most powerful currents, which 

 would have completely saturated steel bars of the same dimen- 

 sions. The plates from which the following measurements have 

 been derived were those already described, with the addition of 

 No. 13, of which the length was 42 millims. ; breadth, 15 mil- 



