on the Polarity of the Diamagnetic Force. 181 



Thus far then the following substances have been submitted 

 to examination : — 



Diamagnetic bodies. Magnetic bodies. 



Bismuth. Penrhyn slate. 



Antimony. Caermarthen slate. 



Heavy glass. Slate perpendicular to cleavage. 



Calcareous spar. Chloride of iron. 



Statuary marble. Sulphate of iron. 



Phosphorus. Carbonate of iron. 



Sulphur. Ferrocyanide of potassium. 



Nitre. Oxide of iron. 



Wax. Iron filings. 



Liquids. Liquids. 



Distilled water. Sulphate of iron. 



Bisulphide of carbon. Muriate of nickel. 



Muriate of cobalt. 



Every substance in each of these lists has been proved to be 

 polar under magnetic influence, the polarity of the diamagnetic 

 bodies being invariably opposed to that of the magnetic ones. 



In his investigation on the supposed polarity of diamagnetic 

 bodies, Mr. Faraday made use of a core of sixpenny pieces, and 

 obtained with it the results he sought. Wishing to add the 

 testimony of silver as a good conductor to that of copper, two 

 cylinders were formed of sixpenny pieces, covered with paper, 

 and submitted to experiment. The following are the results 

 obtained : — 



XXVIII. 

 Silver cylinders (sixpenny pieces). 



Current direct. Current direct. Current direct. 



Position 1. 724 Position 3. 774 Position 3. 804 



The action here was prompt and energetic, strongly contrasted 

 with the neutrality of copper ; but the deflection was permanent, 

 and could not therefore be the result of induced currents. Fur- 

 ther, it was a deflection which shows magnetic polarity, whereas 

 pure silver is feebly diamagnetic. The cylinders were removed 

 and examined between the poles of an electro-magnet; they 

 proved to be magnetic. 



On observing this deportment of the silver, I tried the copper 

 cylinders once more. The results with a direct current were, — 



XXIX. 



Position 1. 766 Position 2. 767 Position 3. 768 



Here almost the same neutrality as before is evidenced. 

 Deeming that the magnetism of the cores of silver was due to 



