306 THE ADDRESSES, LECTURES, ETC., OF 



dependency of my present speculation, the experiments may 

 prove useful in extending our knowledge regarding the laws of 

 dissociation. 



It should be here observed that, according to Professor Stokes, 

 the ultra violet rays are in large measure absorbed in passing 

 through clear glass, and it follows from this discovery that only a 

 small portion of the chemical rays found their way through the tubes 

 to accomplish the work of dissociation. This circumstance being 

 adverse to the experiment only serves to increase the value of the 

 effect observed, whilst it appears to furnish additional proof of the 

 fact, first enunciated by Professor Draper, and corroborated by 

 my own experiments on plants, that the dissociating power of 

 light is not confined to the ultra violet rays, but depends in the 

 process of vegetation chiefly upon the yellow and red rays. 



Assuming, for my present purpose, that dissociation of aqueous 

 vapour was really effected in the experiment just described, 'and 

 assuming, further, that stellar space is filled with aqueous and 

 other vapour of a density not exceeding the a-oV^h part of our 

 atmosphere, it seems reasonable to suppose that its dissociation 

 would be effected by solar radiation, and that solar energy would 

 thus be utilised. The conjoint presence of aqueous vapour, 

 carbonic acid and nitrogen would only serve to facilitate their 

 decomposition, in consequence of the simultaneous formation of 

 hydrocarbons and nitrogenous compounds by combination of the 

 nascent hydrogen and the nitrogen with carbon in a manner 

 analogous to what occurs in vegetation. It is not necessary to 

 suppose that all the energy radiated from the sun into space 

 should be intercepted, inasmuch as even a partial return of heat 

 in the manner described would serve to supplement solar radiation, 

 the balance being made up by absolute loss. To this loss of 

 energy would have to be added that consumed in sustaining the 

 circulating current, which however need not relatively be more 

 than what is known to be lost on our earth through the tidal 

 action, and may be supposed to be compensated as regards the 

 time of solar rotation by gradual shrinkage. 



By means of the fan-like action resulting from the rotation of 

 the sun, the vapours dissociated in space to-day would be drawn 

 towards the polar surfaces of the sun to-morrow, be heated by 

 increase in density, and would burst into flame at a point where 



