Molecular Dissymmetry. ii 



may conceive the oscillatory motion of the light ra}- as 

 taking the path of least resistance, and being, so to speak, 

 twisted in consequence of the obstruction presented by the 

 dissymmetrical arrangement of the atoms or molecules of 

 the substance traversed, or, in other words, by the dissym- 

 metrical nature of the path presented to it. If, now, 

 Faraday's magnetic arrangement be introduced, we may 

 further conceive of the oscillating ether particles being drawn 

 aside to the lines of magnetic force as iron filings are drawn 

 to such lines, the motion being in some way thus compelled 

 to take a new plane. In this case, though the magnetic 

 lines produced in the inorganic medium a twist or rotation 

 of the plane, similar in appearance to the natural rotation in 

 the organic substance, and intensified the rotation in the 

 latter, it could not be said that the causes of the rotation, or 

 the molecular states of the two substances in which the 

 rotation took place, were identical. 



It must be conceded, however, that Faraday appears to 

 go a part of the way with Dr. Tyndall. Faraday tells us 

 that he was satisfied that " the magnetic forces do not act on 

 the ray of light directly and without the intervention of 

 matter, but through the medium of the substance in which 

 they and the ray have a simultaneous existence ; the sub- 

 stances and the forces giving to and receiving from each 

 other the power of acting on the light." This he considered 

 he had proved by demonstrating the non-action of the forces 

 in a vacuum, in air, and in gases ; and that it was also 

 further proved by the special degree in which different 

 substances displayed the phenomena of rotation under the 

 infliuence of the magnetic forces. If the action is direct 

 and irrespective of the substance, then there appears no 

 reason why the magnetic forces should not under all cir- 

 cumstances and in all substances affect the ray of light 

 equally ; and this is not so. Nevertheless Faraday contends 

 that there is a direct relation, though matter is necessary for 



