^{page 680 note *} Particle = unit of ether. Atom or bubble = ordinary atom of matter.

^{page 681 note *} Readers will gather from the present paper that I have altered my mind on this subject.

^{page 684 note *} Two substances of the same kind rubbed together may be electrified if in different physical states. For instance, rough and smooth glass. The explanation is, that in rough glass a greater proportion of the surface of each atom is free from its fellows, and therefore contains a greater quantity of motion than that of those of the smooth glass; the latter is therefore positively electrified, and the former negatively so.

^{page 688 note *} “In the usual notation of dynamics, assuming simple harmonic motion, we have Therefore, when the vibration frequency is increased n times, the displacement produced by the same force becomes 1/n ² of its former value; and so, per vibration, under the action of the same force, the energy involved becomes 1/n ² of its former value. But the number of vibrations per unit time is increased n times, so that the rate of emission of energy, under the usual law of damped vibrations, would become 1/n ^th of the former rate.”

^{page 689 note *} “If μ represent the mass of a particle in an atom of radius r, while there are n such particles per unit area of the surface, the external pressure p is balanced when nuv²=pr. That is when Mv²=3p^V , where M is the mass and V the volume of the atom.”

^{page 690 note *} Elasticity.—I am inclined to think that there must be two conditions of elasticity, viz., the elasticity of great particle-speed and small density, and the elasticity of great particle-density, or close-grainedness, as I have called it, and slow speed. I should say that the permanent gases possess the former and the metals the latter, other substances ranging between these. The former can be overcome by great pressure, but the latter only slightly, or not at all.

^{page 692 note *} It is found that electrified bodies when heated lose their charges, but that negative electrification is more readily discharged than positive. This is in accordance with the present theory, for negative electrification is a lack of electricity which heat can readily supply—that is to say, that some of the latter becomes transformed into the former till the neutral state is reached. In the case of positive electricity the heated body would retain its charge for some time, till by the increase of the vibrations the whole of it would be transformed into heat.

In flames a chemical change is going on where both positive and negative electricity are present and being converted by their great affinity for one another into heat.

^{page 702 note *} The sulphion of sulphuric acid is negative to the hydrogen with which it was united after the latter comes away from it, but before their union the sulphion was positive to the hydrogen, and in the act of union parted with some of its electricity to it, which made the hydrogen positive and the sulphion negative. Similarly the sulphion, before union, is positive to the zinc with which it unites, and during the act of union makes the zinc positive, leaving itself far more negative than when it parted with its hydrogen. This can be explained by the fact that its union with the zinc is far closer than it was with the hydrogen.

^{page 705 note *} There seems to be some difficulty in accepting this statement. There is a liability to come to the conclusion that because the ions are in contact the speeds of their particles must be equalised. But this could never happen, for they cannot have the same speed with different radii or their “centrifugal force” would differ, nor can they have the same radii with different masses or their speeds must differ. The particles of the different ions never come into direct collision, because if they did the ions would break up, and it is chiefly by their centrifugal tendencies that momentum is exchanged.

^{page 707 note *} Compounds would be dissociated by heat in much the same way, the bonds of the positive body being the first to fill up, and the charges of the components would be neutralised by the surrounding neutral bodies.

^{page 709 note *} This property of bodies I propose to call by the name of “Self-Compression.”

^{page 711 note *} Pendulums of the same length have the same period of vibration irrespective of amplitude or weight of bob.

^{page 713 note *} 273° to be added for reduction to absolute temperature.

^{page 714 note *} Assuming, of course, that when atoms have the same atomic volume their particles move with the same speed.

^{page 716 note *} Plus 273° for reduction to absolute temperature.