Bodies are repelled from the Poles of a Magnet. 173 



ting upon tlie bars being proportional to the squares of the 

 number of oscillations, the simple addition of the index figure 

 completes the expression of these forces. 



In these experiments the bismuth bar set across the lines of 

 magnetic force, while the bar of iron set along them ; the former 

 was so cut from the crystalline mass, that the plane of principal 

 cleavage was parallel to the length of the bar, and in the experi- 

 ments hung vertical. I thought it interesting to examine the 

 deportment of a bar of bismuth which should occupy the same 

 position, with regard to the lines of force, as the bar of iron ; 

 that is to say, which should set its length axial. Such a bar is 

 obtained when the planes of principal cleavage are transverse to 

 the length. 



Table V. 

 Bar of bismuth. No. 2. 



Length O'S of an inch ; width 0-13 of an inch ; depth 0-15 

 of an inch. 



Set axial between the excited poles. 



A deportment exactly similar to that exhibited in the fore- 

 going cases is observed here also : up to about 380 the repul- 

 sions are accurately proportional to the squares of the current 

 strengths, and from this point forward they increase in a less 

 ratio. 



A paramagnetic substance was next examined which set its 

 lenn-th at right angles to the lines of magnetic force : the sub- 

 stance was carbonate of iron. The native crystallized mineral 

 was reduced to powder in a mortar, and the powder was com- 

 pressed. It was suspended, like the bismuth, between the flat 

 poles, with its line of compression horizontal. When these poles 

 were excited, the compressed bar set the line of pressure from 

 pole to pole, and consequently its length equatorial. 



