176 Prof. TjTidall on the Nature of the Force by which 



Table XIII. 



Spheres of carbonate of iron. 

 Strength of mas;net. Ratio of attractions. 



m ^ 662 



89 892 



114 1 142 



141 14P 



In confirmation of these results I will cite a series obtained 

 by M. E. Becquerel*, whose experiments first showed that the 

 repulsion of diamaguetic bodies follows the same law as the 

 attraction of magnetic ones. 



Bar of sulphur. 



Length 25 niillims. ; weight 840 milligrms. 



Squares of the Quotients of the repulsions 



magnetic intensities. by the magnetic intensities. 

 36-58 0-902 



27-60 0-929 



26-84 0-906 



16-33 0-920 



The constancy of the quotient in the second column proves 

 that the ratio of the repulsions to the squares of the magnetic 

 intensities is a ratio of equality. 



I will also cite a scries of experiments by Mr. Joulelj which 

 he adduces in confirmation of the results obtained by M. E. 

 Becquerel and myself. 



Bar of bismuth. 



Strength of magnet. Repulsions. 



1 12 



2 22 

 4 42 



Let us contrast these with the results obtained by the same 

 gentleman, by permitting the magnet to act upon a hard mag- 

 netic needle. 



IMagnetic needle. 

 Length 1-5 of an inch. 



Strength of magnet. Attraction. 



1 I 



2 2 

 4 4 



* Annales de Cliimie et de Physique, 3rd series, vol. xxviii. p. 302. 

 t Phil. Mag. 4th series, vol. iii. p. 32. 



