1882.] 



On the Conservation of Solar Energy. 



391 



physical experiments bearing upon the question, all of which have 

 served to strengthen my confidence and ripened in me the determina- 

 tion to submit my views, not without some misgiving, to the touch- 

 stone of scientific criticism. 



For the purposes of my theory, stellar space is supposed to be filled 

 with highly rarefied gaseous matter, including probably hydrogen, 

 oxygen, nitrogen, carbon, and their compounds, besides solid materials 

 in the form of dust. This being the case, each planetary body would 

 attract to itself an atmosphere depending for its density upon its 

 relative attractive importance, and it would not seem unreasonable to 

 suppose that the heavier and less diffusible gases would form the staple 

 of these atmospheres ; that, in fact, they would consist mostly of nitro- 

 gen, oxygen, and carbonic anhydride, whilst hydrogen and its com- 

 pounds would predominate in space. 



But the planetary system, as a whole, would exercise an attractive 

 influence upon the gaseous matter diffused through space, and would 

 therefore be enveloped in an atmosphere, holding an intermediate posi- 

 tion between the individual planetary atmospheres and the extremely 

 rarefied atmosphere of the stellar space. 



In support of this view it may be urged, that in following out the 

 molecular theory of gases as laid down by Clausius, Clerk Maxwell, 

 and Thomson, it would be difficult to assign a limit to a gaseous atmo- 

 sphere in space and, further, that some writers, among whom I will here 

 mention only Grove, Humboldt, Zoellner, and Mattieu Williams, have 

 boldly asserted the existence of a space filled with matter, and that 

 Newton himself, as Dr. Sterry Hunt tells us in an interesting paper 

 which has only just reached me, has expressed views in favour of such 

 an assumption. Further than this, we have the facts that meteorolites 

 whose flight through stellar, or at all events through interplanetary 

 space, is suddenly arrested by being brought into collision with our 

 earth, are known to contain as much as six times their own volume of 

 gases taken at atmospheric pressure ; and Dr. Flight has only very 

 recently communicated to the Royal Society the analysis of the 

 occluded gases of one of these meteorolites taken immediately after 

 the descent to be as follows : — 



C0 2 . 

 CO 

 H . 

 CHi 

 K. 



100 -oo 



0T2 

 31 -88 

 45 79 



17-66 



It appears surprising that there was no aqueous vapour, considering 

 there was much hydrogen and oxygen in combination with carbon, but 



