344 FRAGMENTS OF SCIENCE 



the conductor the more exalted will be the effect. This 

 requirement was complied with. 



Cylinders of antimony were substituted for those of 

 bismuth. This metal is a better conductor of electricity, 

 but less strongly diamagnetic than bismuth. If therefore 

 the action referred to be due to induced currents, we ought 

 to have it greater in the case of antimony than with bis- 

 muth; but if it springs from a true diamagnetic polarity, 

 the action of the bismuth ought to exceed that of the anti- 

 mony. Experiment proves this to be the case. Hence 

 the deflection produced by these metals is due to their 

 diamagnetic, and not to their conductive capacity. Cop- 

 per cylinders were next examined: here we have a metal 

 which conducts electricity fifty times better than bismuth, 

 but its diamagnetic power is nearly null; if the effects be 

 due to induced currents we ought to have them here in 

 an enormously exaggerated degree, but no sensible deflec- 

 tion was produced by the two cylinders of copper. 



It has also been proposed by the opponents of diamag- 

 -netic polarity to coat fragments of bismuth with some in- 

 sulating substance, so as to render the formation of induced 

 currents impossible, and to test the question with cylin- 

 ders of these fragments. This requirement was also ful- 

 filled. It is only necessary to reduce the bismuth to pow- 

 der and expose it for a short time to the air to cause the 

 particles to become so far oxidized as to render them per- 

 fectly insulating. The insulating power of the powder was 

 exhibited experimentally; nevertheless, this powder, en- 

 closed in glass tubes, exhibited an action scarcely less 

 powerful than that of the massive bismuth cylinders. 



But the most rigid proof, a proof admitted to be con- 

 clusive by those who have denied the antithesis of mag- 



