288 Prof. Norton on Molecular Physics. 



must be attributed to the molecular polarization that precedes 

 and accompanies the act of combination, in conjunction with, 

 under special circumstances, the exertion of a separating force 

 due to heat, light, or an electric current. We have seen already, 

 in considering the process of decomposition of a molecule of 

 water by the chemical action of zinc (vol. xxx. p. 110), that such 

 action upon one of the elements of a binary compound tends to 

 separate it from the other, if the two are in conducting commu- 

 nication — as they would be in every true compound molecule, by 

 reason of the electric aether condensed between them. 



Chemical Action of the Actinic Rays. — We understand by the 

 actinic rays, the solar rays of high refrangibility, which are capa- 

 ble of producing chemical effects entirely distinct from the effects 

 of heat. From the view we have taken of the origin of rays of 

 heat and light (vol. xxviii. p. 430 &c), we are led to conceive of all 

 the solar radiations as essentially of the same nature, and differing 

 only in the rapidity of vibration and in the intensity of the im- 

 pulses propagated in the ray, and that they owe these differences 

 to the fact that they originate in the vibrations of the atomettes 

 of molecular atmospheres posited at various distances from the 

 central atoms of the molecules (/. c. p. 430) . The most refrangible 

 actinic rays should then emanate from the atomettes th,at lie 

 at the greatest distances from these atoms. 



The chemical action of light, and of the actinic rays in general, 

 appears to be a consequence of the feeble repulsive individual 

 impulses propagated in the rays that originate in the upper por- 

 tions of molecular atomospheres. Such feeble impulses cannot 

 penetrate far into the molecular atmospheres upon which they 

 fall, and must pass around them. They should accordingly tend 

 to urge a portion of the electric aether that may lie in their route 

 around to the further side of the molecule, and so to bring it 

 into a state of positive electrization. The nature of the action 

 that will ensue in consequence, upon the next molecule beyond 

 that which receives the ray, must depend upon whether there is 

 an electric conducting connexion between the two or not. If 

 there be such connexion, the tendency of the action of the free 

 electricity set in motion will be to separate or decompose the 

 two molecules, which, in the case supposed, will be chemically 

 united. The action here considered is essentially the same as 

 that which occurs in the decomposition of water by zinc (vol. xxx. 

 p. 110). Most cases of the chemical action of light would seem 

 to be explicable upon this idea. Thus, we may explain the action 

 of light upon an explosive mixture of chlorine and hydrogen by 

 the decomposition of the elementary molecules of the two gases, 

 and the resulting formation of two molecules of hydrochloric 

 acid. The reduction of the chloride of silver to a subchloride by 



