326 FRAGMENTS OF SCIENCE. 



fest polar action of the bismuth cylinders ugon the 

 magnet; one pair of ends deflecting it in one direction, 

 and the other pair deflecting it in the opposite direc- 

 tion. 



Substituting for the cylinders of bismuth thin 

 cylinders of iron, of magnetic slate, of sulphate of iron, 

 carbonate of iron, protochloride of iron, red ferrocya- 

 nide of potassium, and other magnetic bodies, it was 

 found that when the position of the magnetic cylinders 

 was the same as that of the cylinders of bismuth, the 

 deflection produced by the former was always opposed 

 in direction to that produced by the latter; and hence 

 the disposition of the force in the diamagnetic body 

 must have been precisely antithetical to its disposition 

 in the magnetic ones. 



But it will be urged, and indeed has been urged 

 against this inference, that the deflection produced by 

 the bismuth cylinders may be due to induced currents 

 excited in the metal by its motion within the helices. 

 In reply to this objection, it may be stated, in the 

 first place, that the deflection is permanent, and can- 

 not therefore be due to induced currents, which are 

 only of momentary duration. It has also been urged 

 that such experiments ought to be made with other 

 metals, and with better conductors than bismuth; for 

 if due to currents of induction, the better the con- 

 ductor the more exalted will be the effect. This re- 

 quirement was complied with. 



Cylinders of antimony were substituted for those of 

 bismuth. This metal is a better conductor of elec- 

 tricity, 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 anti- 

 mony than with bismuth; but if it springs from a true 

 diamagnetic polarity, the action of the bismuth ought 



