88 " Attraction of Gravitation 



undetermined way, the moleculai' energy of these waves is 

 converted into the kinetic energy of the piece of iron. So in 

 the case of a permanent steel magnet, it has been shown 

 by Clerk-Maxwell, Verdet, De La Rive, and Wertheim, that 

 the attractive force is due to the molecular state both of the 

 attracting and the attracted body. 



Now, take the case of a steel magnet which has been 

 heated and allowed to cool. It has lost its special molecular 

 energy, and its special attractive force ; but it now possesses 

 the ordinary form of energy common to all matter, and like- 

 wise possesses the ordinary form of attraction common to all 

 matter. Since, then, in its former state, its attractive power 

 is known to be due to the energy of its atoms, there is a 

 strong presumption, in the absence of any other explanation, 

 that the attraction and the molecular state in the second 

 condition, are causally connected. 



The following, therefore, is the theory to which the facts 

 point : — When two bodies are placed near one another, the 

 internal energy with which each is actuated is radiated into 

 space, but such of it as is intercepted by the other is con- 

 verted into kinetic energy in a manner analogous to that in 

 which the molecular vibrations of an electro-magnet radiate 

 and produce kinetic energy in the attracted iron. 



If this theory could be shown to be true, it would explain 

 certain facts which seem otherwise to be inexplicable. 



For instance, suj)pose a mass of iron at the surface of the 

 earth to weigh one ton ; then, if it were to be carried fifteen 

 hundred miles upwards from the surface, it would weigh only 

 half a ton. Now, what would become of the lost weight ? 

 Faraday spent some months in trying to discover if weight 

 lost in this manner is turned into electricity ; but his experi- 

 ments gave no hopeful result. No other explanation has 

 been given of this apparent disappearance of something from 

 existence. But it is possible, that though this particular 

 mass of iron has lost something, yet that something has, 

 nevertheless, not been lost from existence. And this is the 

 result our proposition would give. For if we imagine a 

 body in a certain position to receive a certain amount of the 

 molecular waves proceeding from another body, then, when 

 removed to twice the distance, it would receive only one- 

 fourth the amount it previously received. The remaining 

 three-fourths would be lost to this particular body, but would 

 not be lost from existence — it would travel out into space ; 



