498 report— 1878. 



from one another, still, as explained in their paper on the ' Viscosity of Dielectrics,' 

 a succession of rapidly reversed charges would he accompanied hy true electric 

 conduction ; in fact, that it would be well worthy of consideration whether the 

 explanation of the result which Mr. Gordon had brought to their notice at this 

 meeting, viz., that his new method of measuring specific inductive capacity of solid 

 dielectrics had given the old results, might not be found to consist in this conduction 

 — this viscous conduction he might term it, although in reality there was but one 

 kind of conduction, the conversion of electric energy into heat — for this conduction 

 would occur unequally in the two apparently balanced condensers, since the two 

 dielectrics varied in viscosity, consequently the balance of capacities was not a 

 real one. 



Nevertheless Professor Ayrton thought it highly important that careful experi- 

 ments should be made, both with constant and with rapidly reversed charges, on 

 the inductive phenomena observed in such a water condenser as he had described. 



The abnormal rise in the specific inductive capacity of bees' wax, on solidifying, 

 which the experiments of Professor Perry and himself had shown, coincided with 

 an increase in the index of refraction ; he regarded this as furnishing an important 

 addition to the experimental proof of Professor Clerk Maxwell's electro-magnetic 

 theory of light, and he hoped that some of those philosophers of Trinity College, 

 Dublin, who had so successfully turned their attention to the elucidation of the 

 molecular vibrations causing Crookes's force, would give their views on the molecular 

 vibrations accompanying wave motion and electric induction. 



He thought that the experiments described in the paper on bees' wax and lead 

 chloride showed, in a sufficiently satisfactory way, that, where the resistance of an 

 electrolyte diminished by electrification, it was due to the electromotive force 

 employed being sufficiently great to decompose the damp in the pores of the elec- 

 trolyte ; but, in view of the fact that the resistance of water itself increased by 

 electrification, it seemed to follow that the products of the decomposition of the 

 damp must act chemically on the solid electrolyte and cause deterioration, and 

 hence a smaller specific resistance. But if there were deterioration we should 

 expect that the specific resistance of the material would steadily diminish day by 

 day, a result that was not obtained in the experiments of Professor Perry and 

 himself, on bees' wax at any rate, as will be seen on examining the table given 

 in their paper in the 'Philosophical Magazine 'for August. He therefore concluded 

 that further experiments on electrolytes, in which resistance diminishes by electri- 

 fication, were necessary to make the explanation quite complete. 



12. Theory of Voltaic Action* By J. Brown. 



The author described some experiments made with a Volta's condenser having 

 plates of iron and copper, and with a ring half of copper and half iron, which 

 show that the difference of electric potential of these metals when in contact 

 depends on the atmosphere surrounding them. 



"While in the ordinary atmosphere iron is positive to copper, in an atmosphere 

 of hydrogen sulphide copper is positive to iron. These effects are explained by 

 the chemical theory of electricity, as due in the first-mentioned case to the superior 

 chemical affinity of the iron for the oxygen of the watery vapour, and other oxygen 

 compounds present in the air ; in the second, to the greater affinity of the copper 

 for the sulphur of the hydrogen sulphide. 



13. Mutual Action of Vortex Atoms and Ultramundane Corpuscles. 

 By Professor G. Forbes. 



It is well known that amongst the numerous theories which have dealt with 

 the form of an atom, there is only one which is in accordance with the properties 



* A description of the experiments is given in the 'Phil. Mag.,' August, 1878. 



