714 PLiJCKEK ON THE DETERMINATION OF THE 



minute particles of any magnetic substances, placed in succession 

 at the same spot, experience attractions, which stand in any 

 relation, this relation is not altered when both the particles are 

 placed in succession in any other spot, provided it be the same for 

 both; an admission which must necessarily be made, if magnetic 

 forces diminish in any definite way with the distance. It then 

 follows mathematically from this admission, that the relation of 

 the attraction of the entire mass is also the relation of the attrac- 

 tion of the individual atom ; supposing merely that the magnetic 

 attraction of each individual atom is not disturbed by the mag- 

 netic excitement of the remaining atoms, and that the attracted 

 mass does not by its reaction increase the magnetism of the pole 

 of the magnet. On this supposition, the relation of the attrac- 

 tion of the masses remains unchanged even when the form of 

 the watch glass is exchanged for any other form, provided it 

 remain the same during the comparison of the attractions with 

 each other. 



If, where previously there existed only a single atom of iron, 

 there are now two or three of the same atoms of iron, or in other 

 woi'ds, if in the same space twice or thrice as much iron is xmi- 

 formly distributed in a definite chemical compound, according to 

 the above method of deciding the magnitude of the attraction, 

 inasmuch as it emanates immediately from the pole of the magnet, 

 it is evidently twice or thrice as great. 



4. When the substance to be examined as regards magnetism 

 is of a greasy or waxy consistence, the watch-glass may be com- 

 pletely filled with it in the same manner as with fluids, as may 

 also be effected when it is susceptible of reduction to fine powder. 

 In the latter case, for the purpose of diminishing the attraction, 

 the powder may be mixed with extreme uniformity with fresh 

 hog's lard, and the mixture placed in the watch-glass. 



If, for instance, we take on the one hand finely divided iron 

 and on the other finely divided nickel, both at first in the same 

 atomic number, or secondly in equal weight, and mix it with 

 a given quantity of lard, and then fill the watch-glass with the 

 mixture, the relative of the attractions in the first case gives 

 the relative of the magnetism of the atoms of the two metals, or, 

 in the second supposition, the relative magnetism of these metals 

 when of the same weight. 



5. To determine the strength of the attraction, I place the 

 watch-glass with its contents and its cover in a thin ring of brass. 



