MAGNETIC AND DIAMAGNETIC ACTION COMPARED. 
55 
2426. In reference to the metals, as well as the diamagnetics not of that class (2286.), 
it is satisfactory to have such an answer to the opinion that all bodies are magnetic 
as iron, as does not consist in a mere negation of that which is affirmed, but in proofs 
that they are in a different and opposed state, and are able to counteract a very con- 
siderable degree of magnetic force (2448.). 
2427. As already stated, the magnetic force is so strikingly distinct in its action 
upon bodies of the magnetic and the diamagnetic class, that when it causes the 
attraction of the one it produces the repulsion of the other; and this we cannot help 
referring, in some way, to an action upon the molecules or the mass of the substances 
acted upon, by which they are thrown into different conditions and affected accord- 
ingly. In that point of view it is very striking to compare the results with those 
which are presented to us by a polarized ray, especially as then a remarkable differ- 
ence comes into view ; for if transparent bodies be taken from the two classes, as for 
instance, heavy glass or water from the diamagnetic, and a piece of green glass or a 
solution of green vitriol from the magnetic class, then a given line of magnetic force 
will cause the repulsion of one and the attraction of the other; but this same line of 
force which thus affects the particles so differently, affects the polarized ray when 
passing through them precisely in the same manner in both cases; for the two 
bodies cause its rotation in the same direction (2160. 2199. 2224.). 
2428. This consideration becomes even more important when we connect it with 
the diamagnetic and the optical properties of bodies which rotate a polarized ray. 
Thus the iron solution and a piece of quartz, having the power to rotate a ray, point 
by the influence of the same line of magnetic force, the one axially and the other 
equatorially ; but the rotation which is impressed on a ray of light by these two 
bodies, as far as they are under the influence of the same magnetic force, is the same 
for both. Further, this rotation is quite independent of, and quite unlike that of the 
quartz in a most important point ; for the quartz by itself can only rotate the ray in 
one direction, but under the influence of the magnetic force it can rotate it both to 
the right and left, according to the course of the ray (2231. 2232.). Or, if two pieces 
of quartz (or two tubes of oil of turpentine) be taken which can rotate the ray different 
ways, the further rotative force manifested by them when under the dominion of the 
magnetism is always the same way ; and the direction of that way may be made 
either to the right or left in either crystal of quartz. All this time the contrast be- 
tween the quartz as a diamagnetic, and the solution of iron as a magnetic body remains 
undisturbed. Certain considerations regarding the character of a ray, arising from 
these contrasts, press strongly on my mind, which, when I have had time to submit 
them to further experiment, I hope to present to the Society. 
2429. Theoretically, an explanation of the movements of the diamagnetic bodies, 
and all the dynamic phenomena consequent upon the actions of magnets on them, 
might be offered in the supposition that magnetic induction caused in them a con- 
trary state to that which it produced in magnetic matter ; i. e. that if a particle of 
