266 Prof. A. P. Cliaitock on the Forces at the 



law of force expressed by 4ze 1 s^e 2 s 2 l i^2 4 - The true significance 

 of the relation of Mills seems to me to be the indication of 

 broad simple dynamical law in the kinetics of electrons 

 forming atoms. These ideas lead at once to the following 

 speculation. 



11. The nature of chemical potential energy. 



If the view proposed in the last section is correct, namely, 

 that a part of the latent heat of vaporization of a liquid is 

 kinetic energy supplied to the electrons of atoms to establish 

 dynamical equilibrium under changed conditions of hetero- 

 geneity, it follows that the heat of chemical reactions is 

 energy given out because of changed heterogeneity of the 

 electrons in the reacting atoms. Is it possible that the pairs 

 of electrons of two chemically combined atoms mingle like 

 the molecules of two mixed liquids? Even if such mixture 

 does not take place, the close approach of two different 

 swarms of pairs of electrons may produce instability in the 

 dynamical equilibrium of each and a fall into a new position 

 of equilibrium with evolution of heat in the process. The 

 internal energy of the radium atom is of the type here 

 supposed to reside in all atoms as kinetic energy of the 

 constitutive pairs of electrons. 



Melbourne, April 1910. 



XXI. On the Forces at the Surface of a Needle-Point dis- 

 charging in Air. By A. P. Chattock, Professor of 

 Physics in the University of Bristol *. 



THE strength of the field at a spherically ended electrified 

 needle-point may be measured in terms of the pull of 

 the lines of force upon its surface |, if the pull is due to the 

 lines of force alone ; a condition which is only strictly 

 fulfilled when the point is not discharging. 



In 1897, while attempting to extend this method to a 

 discharging point, I tried the effect of supplying the latter 

 with ions of opposite sign to itself obtained from a second 

 point in its neighbourhood. Some rather interesting effects 

 were observed in air at atmospheric pressure ; but as at the 

 time no explanation of them was forthcoming their discussion 

 was postponed, and they remained unpublished. 



Recently while looking over the record of the experiments 



* Communicated bv the Author. 



t Chattock, Phil. 'Mag. [5] xxxii. p. 285. Young, Phil. Mag. [6] 

 xiii. p. 542. 



