378 Dr. G. J. Stoney on the 



which, judging from the transparent gases, we may conclude 

 would be 1*4, furnished by 5 degrees of freedom. The B6 

 motions in question would probably add something like three 

 times 6 or 8 more degrees of freedom if the molecule stood 

 alone, but by reason of the linkage only some fraction of this 

 addition has to be made. It appears from the table that in 

 chlorine, which is the least deeply-coloured gas, that is, the 

 gas in which the linkage is most effective, the addition to be 

 made is of 1*2 degrees of freedom ; while in bromine and 

 iodine an addition of 1*9 degrees of freedom has to be made, 

 indicating that the linkage is more lax in these gases. 



Since in so many bodies the electrons seem to be associated 

 with events which are very much isolated from those that are 

 chiefly affected by the encounters, the modification of the 

 dynamical condition which is introduced through them may 

 be regarded as a perturbation. It would perhaps not be 

 impracticable to discover in what way perturbating forces, not 

 obevino; the conditions of the Boltzmann-Maxwell theorem, 

 can influence the results of that theorem. This would be of 

 much value ; and if it can be made out, will perhaps explain 

 why in some transparent diatomic gases the value of 7 is 

 above 1*4, while it is less than that value in others. The 

 reason probably is that in hydrogen, nitrogen, and hydro- 

 bromic acid the motions associated with their two Ba degrees 

 of freedom are able to rouse a certain amount of activity in 

 adjoining B5 events, and that thus a part of their energy gets 

 to be exposed to linkage. 



Hitherto we have regarded molecules as acted on in two 

 ways only — by dynamical interactions between or within the 

 molecules, and by the effect of electromagnetic waves on 

 such of the electrons as are undisguised charges of electricity. 

 But there are other ways in which molecules may be acted 

 on, of which the most conspicuous intervenes energetically on 

 those critical occasions when chemical reaction takes place. 

 Here it is the electrons that are primarily concerned, as is 

 manifest from Faraday's law of electrolysis. In cases of 

 friction also, or of disruption of a crystal, it is manifest that 

 some of the electrons are started into activity. In fact it 

 may be presumed that the intermolecular bonds within a 

 crystal are fundamentally of the same kind as the interatomic 

 bonds within a molecule, and that in both it is interaction 

 between electrons that is principally called into play. It 

 should also be noted that the number of electrons within an 

 atom may be greater than its place in Mendeleeff's table 

 would seem to suggest, as is, for example, evidenced by the 

 chemical behaviour of potassium. 



