SIXTH ORDINARY MEETING. 39 



By the way, we may notice that the term luminiferous ether which 

 is derived from its connection with the theory of light, and which 

 does not at all suggest the varied functions which this mysterious 

 medium is now supposed to fulfil is fast losing its appropriateness. 

 In view of the recent advances in Molecular Science, energipherous 

 would seem a much fitter term. 



Though this name is suggested by the nature of radiant heat the 

 -coining of a new word is further justified by the views as to 

 the nature of electricity, magnetism, &c, advanced by Maxwell, 

 and now held by the leading investigators in that important field of 

 knowledge. 



Further, analysing light by the spectroscope, and remembering 

 that on the undulatory theory of light, which is one of the most 

 ■completely verified hypotheses of modern science, refrangibility is pro- 

 portional to the wave-length, we can be certain that in any given 

 section of the spectral band, whether in the doubtfully so-called 

 thermal, luminous or actinic portions, we have vibrations of a deter- 

 minate wave-length. 



Now it is found by means of the thermopile that the luminous 

 portion of the spectral hand has a heating effect, proving that 

 luminous rays are also thermal rays, or that the identical rays, which 

 falling on the optic nerve would excite the sensation of light, when 

 allowed to strike the face of the thermopile produce the effects 

 •of heat. 



This important identity is rendered probable by the fact that cer- 

 tain substances absorb light, the only explanation of the disappear- 

 ance being that the substances are more or less heated. Leslie has 

 shown experimentally that this heating does in fact take place. 



Combining this conclusion with the property known as the trans- 

 mutation of rays, a property discovered by Stokes, who succeeded in 

 .so diminishing the wave-lengths of the ultra-violet rays of the 

 spectrum (by the interposition of thin plates of certain substances) 

 as to render them visible, it follows that the fact of heat-producing 

 chemical decomposition which can only be effected by an acceleration 

 in the motions of the constituent atoms of the molecules, or in other 

 words by interatomic forces, does not at all prove that heat consists 

 in atomic as distinguished from molecular vibrations. 



Even should Lockyer's hypothesis that in the enormously heated 

 atmosphere of the sun the supposed elementary bodies are dis- 



