produced by Magnetization, 



463 



was then dried and placed within the spiral, very near the mag- 

 netometer, and its own magnetism, as well as that induced in it 

 by a magnetizing current (produced by a 6-celled Grove's battery), 

 was measured. In two such experiments I found — 



1. 2. 



Original magnetism . . . 3*60 3*59 



Temporary 3*70 3*69 



Permanent 3'60 3*58 



Magnetic plates broader, but equally thin with the above, con- 

 sisting of precipitates of iron on the surface of silver, easily acquired 

 a temporary magnetism greater than their original magnetism ; 

 but neither by the most powerful current, nor by rubbing them 

 with the pole of a powerful plate-magnet, could a permanent 

 magnetism be induced in them greater than that possessed by them 

 originally. 



Thicker magnetic plates not only exhibited a greater difference 

 between their original and temporary magnetic powers, but their 

 permanent was greater than their original magnetism. 



Length 



Breadth 



Weight 



Specific gravity 



Thickness 



Original magnetism 



Temporary magnetism 



Permanent magnetism 



After friction with magnet 



5. 



72 millims. 

 15 „ 



8-825 grm, 



6-81 



1-2 

 19-36 

 64-5 

 24-28 

 22-37 



G. 



33 millims. 



M >, 



3-246grm, 



6-63 



1-06 

 16-34 

 35-38 

 18-26 

 16-90 



In experiments 3 to 6, a six-celled Groye's battery was em- 

 ployed. 



If we suppose that magnetizing currents effect a separation of 

 the two magnetic fluids in the metallic mass, which separation 

 partly continues after the cessation of the current only on 

 account of its coercive power, it is difficult to understand why 

 different magnets give results on measurement so totally at 

 variance. We must suppose that the coercive power of thin 

 magnets is greater than that of thick ones, which, to say the 



