Intelligence and Miscellaneous Articles. 479 



previously developed by the combination. Prom this it follows 

 evidently that this return of the elements towards the centre would 

 contribute nothing at all towards the conservation, or rather the 

 continuous reproduction, of the solar temperature. 



It seems to me that Mr. Siemens's theory may be subjected to 

 another decisive critical test. If the solar radiation, or say the 

 heat, whether visible or not, emitted or sent off by any celestial 

 body, during its course effects the chemical dissociation of the 

 hypothetical compounds disseminated in stellar space, the intensity 

 of this radiation must necessarily be reduced by the positive work 

 effected, and all that serves for this work is lost for the visibility 

 of the star. 



From this, then, it follows that the lustre of the sun, of the 

 stars, and of the planets must diminish according to a much more 

 rapid law than that of the inverse proportion of the square of the 

 distances. I say much more rapid; but we must say extremely 

 rapid. In fact, from the moment when the recombination of the 

 elements at the surface of the Sun would be capable of regenerating 

 the heat emitted, it is evident that ail this emitted heat would be 

 employed in its turn in dissociating the chemical compounds in 

 space. In order that the Sun could be thus continually maintained 

 in its energy, it would be necessary that the distance at which it 

 is visible, far from being unlimited as it probably is, should, on the 

 contrary, be restricted ; for wherever it would be still visible there 

 would be light not employed in chemical dissociation, and conse- 

 quently there would still be a definite loss possible. Nothing in 

 the aspect of our planets and their satellites, it seems to me, 

 authorizes us to assume that there is any other reduction in the 

 brilliancy of the light than that resulting from the inverse propor- 

 tion of the square of their distance from the central body. We 

 see stars the light of which has taken at least three years, and 

 others of which the light has perhaps taken thousands of years to 

 reach us. None of this light, therefore, has been employed in 

 chemical dissociation ; nothing could have been restored to them 

 by the mode indicated by the ingenious theory of Mr. Siemens. 



May I be permitted, in concluding this note, to revert to the 

 objection formulated by M. Faye, and to render it in some degree 

 palpable by a numerical example? In an extensive work upon 

 which I am engaged, upon the constitution of the stellar space, I 

 naturally examine into the consequences that the resistance of a 

 gas diffused in space would have upon the movements of the 

 planets. Erom this work I extract an example relating to the 

 application of analysis to the motion of our Earth. According to 

 Laplace, the diminution or augmentation which one may attribute 

 to the duration of our sidereal year 3000 years ago, taking into 

 account the uncertainty of the observations, would be 90 seconds 

 at the maximum (a modification of which, however, there is nothing 

 to demonstrate the reality). Accepting a reduction of this amount 

 as real, I inquire what density a gas would need to have to produce 



