﻿56 Dr. C. V. Burton on the 



the influence of external charges, currents, or magnets. In 

 the present state of science, indeed, such words appear neces- 

 sary to the completeness of demonstration, but they do not 

 need to be considered in any of our deductions from the 

 theorem, and for my own part I am persuaded that in reality 

 there is nothing corresponding to the possibility which they 

 suggest. 



Consider now the case of any body whatever, at any tem- 

 perature other than absolute zero. We know that electro- 

 magnetic radiations will spread out into the ether surrounding 

 the body, and we must suppose that the intermolecular spaces 

 within the body are also traversed by electromagnetic dis- 

 turbances. Let us suppose then, for a moment, that in the 

 molecules of the body there are some finitely conductive 

 portions which are not enclosed in perfectly conductive en- 

 velopes. The electromagnetic disturbances will give rise to 

 currents of conduction in these portions, and accordingly 

 energy will be degraded into a form which is not heat, since it 

 consists, not in the motion or relative positions of molecules 

 or appreciable parts of molecules, or in electromagnetic dis- 

 turbances of the intervening ether, but in something much 

 more fine-grained. We shall thus have a continual degradation 

 of heat into energy of a lower form ; for the electromagnetic 

 " damping " of the finitely conductive bodies involves a con- 

 tinual drain on the energy of internal radiation, and hence 

 indirectly on the energy of the molecules, so that heat will be 

 automatically dissipated in the interior of the body. This 

 process, in which the radiative molecules are continually 

 imparting to the ether more energy than they receive in 

 return, may be compared to the surface cooling of an isolated 

 body which radiates towards colder surroundings. 



Even if we suppose the finitely conductive bodies to be 

 extremely small and their conductivity to be either extremely 

 small or extremely great, it is not hard to see that the rate of 

 absorption of heat must be tremendous ; and when we con- 

 sider (for example) the effect which even a very slow absorp- 

 tion, continued for millions of years, would have had on the 

 temperature of our planet, we must admit that the absence of 

 that dissipation of heat implied in the denial of Theorem I. has 

 been established with an exactitude almost unparalleled. Thus 

 the theorem is established. 



3. In connexion with this result we are reminded that 

 Poisson's theory of dielectrics requires the molecules of in- 

 sulating substances to possess some conductive portions, though 

 whether the conductivity of such portions is finite or infinite 





