Bodies are repelled from the Poles of a Magnet. 167 



cloven from the ci'ystalline mass, is suspended from ;the angle 

 at which the ci-ystallographic axis issues, there is great difficulty 

 in causing the plate to set axial. If the points are neai", on 

 exciting the magnetisui the whole mass springs to one or the 

 other of the points ; and when the points are distant, the plate, 

 although its length may be twenty times its thickness, will set 

 strongly equatorial. An excitation by one cell was sufficient to 

 produce this result. In the experiment cited the residual mag- 

 netism was found to answer best, as it permitted the ends of 

 the plate to be brought so near to the points that the mass was 

 pulled into the axial position. When the magnet was more 

 strongly excited, and the plate raised so far above the points as 

 to prevent its springing to either of them, it was most interesting 

 to watch the struggle of the two opposing tendencies. Neither 

 the axial nor the equatorial position could be retained ; the plate 

 would wrench itself spasmodically from one position into the 

 other, and, like the human spirit operated on by conflicting 

 passions, find I'est nowhere. 



The conditions which determine the curious effects described 

 in the present chapter may be briefly expressed as follows : — 



An elongated diamagnetic body being suspended in the 

 magnetic field, if the shortest horizontal dimension tend, in 

 virtue of the internal structure of the substance, to set equatorial, 

 it is opposed by the tendency of the longest dimension to take 

 up the same position. Between the pointed poles the influence 

 of length usually predominates; above the points and below 

 them the directive action due to structure prevails. 



Hence, the rotation of such a diamagnetic body, on being raised 

 or lowered, is always from the equatorial to the axial position. 



If the elongated mass be magnetic, and the shortest dimension 

 of the mass tend, in virtue of its structure, to set from pole to 

 pole, it is opposed by the tendency of the longest dimension 

 to take up the same position . Between the points the influence 

 of length is paramount ; above and below the points the influence 

 of structure prevails. 



Hence, the rotation of magnetic bodies, on being raised or 

 lowered, is always from the axial to the equatorial position. 



The error of the explanation which referred many of the above 

 actions to the presence of two conflicting forces, one of which 

 diminished with the distance in a quicker ratio than the other, 

 lies in the supposition, that the assuming of the axial position 

 proved a body to be magnetic, while the assuming of the equa- 

 torial position proved a body to be diamagnetic. This assump- 

 tion was perfectly natural in the early stages of diamagnetic 

 research, when the modification of magnetic force by structure 

 was unknown. Experience however proves that the total mass 



