12 Mr Faraday on 



the action of that relation. " That magnetic force acts upon 

 the ray of light always with the same character of manner, 

 and in the same direction, independent of the different 

 varieties of substance, or their states of solid or liquid, or 

 their specific rotative force, shows," he says, "that the 

 magnetic force and the light have a direct relation ; but that 

 substances are necessary and that these act in different 

 degrees, shows that the magnetism and the light act on 

 each other through the intervention of matter." 



Moreover, it is clear that Faraday held that the magnetic 

 influence effected some change in the state of the matter, of 

 which the rotation of the ray was a symptom. " It cannot 

 be doubted," he goes on to say, " that the magnetic forces 

 act upon and affect the internal constitution of the dia- 

 magnetic just as freely in the dark as when a ray of 

 light is passing through it, though the phenomena produced 

 by light seem, as yet, to present the only means of observing 

 this constitution and change." Further, he adds, "any 

 such change as this must belong to opaque bodies, such as 

 wood, stone, and metal, for as diamagnetics there is no dis- 

 tinction between them and those which are transparent." And 

 then, proceeding to point out that the substances in question 

 are not made into magnets, he remarks that the " molecular 

 condition" of these bodies, when in the state described, 

 must be a "new magnetic condition" distinct from that 

 of magnetized iron, and that the force which the matter in 

 this state possesses must be "a new magnetic force," or 

 " mode of action " of matter. 



Now, accepting this exposition of Faraday's, I submit 

 that we are still a long way from being justified in assuming 

 that the induced state of the substance is, as Dr. Tyndall 

 assumes, the result of a displacement of symmetry by 

 Pasteur's molecular dissymmetry ; or that the fact that a new 

 mode of action on light is induced, which resembles the 

 natural rotatory influence of organic compounds, in any way 



