OF ARTS AND SCIENCES. 



197 



In Series I. and 11. the distance between the poles of the magnet was 

 not observed. These distances probably were not the same, for the pole 

 pieces were removed in changing condensers. 



Tables III. and IV. Magnetic force perpendicular to the plates 

 of the single condenser. This was made of two disks of copper eight 



TABLE III. 



TABLE IV. 



centimeters in diameter, with a sheet of mica between them. Between 

 the two series of experiments the direction of the magnetic force was 

 reversed. An increase of capacity equal to 3h per cent is shown 

 in both tables. Hence we conclude that tlie change in capacity is not 

 reversed in sign with the reversal of the direction of the magnetic 

 force. 



