THE TWO COMETS OF THE YEAR 1868- 177 



and unchangeable a substance as carbon, and thus, in 

 place of an almost inconceivable intensity of cold we 

 find the evidence of intense heat. 



It seems impossible, at present, to suggest any ex- 

 planation of the observed phenomena. That carbon 

 exists out yonder in space in the state of luminous gas 

 or vapour, is the one fact of which alone we can 

 be certain. Dr. Huggins in his treatment of this fact 

 suggests the possibility that the carbon may be divided 

 into particles so minute, that as the comet approaches 

 the sun, more of the sun's heat is gathered up, so to 

 speak, and that thus the carbon is volatilised. He also 

 points to phenomena of phosphorescence and fluores- 

 cence in illustration of the appearance presented by 

 the comet's spectrum ; but without suggesting any 

 association between these phenomena and those pre- 

 sented by comets. 



One cannot help associating the new views thus 

 opened out to us respecting comets, with the discovery 

 recently made that the meteoric bodies which flash 

 singly or in showers across our skies belong in reality 

 to the trains of comets. We have now every reason to 

 believe that there is not a single member of the me- 

 teoric systems, not a single aerolite, bolide, or fire-ball, 

 that has not belonged once upon a time to a comet. 

 The evidence on which this view is founded, though it 

 may seem insufficient at a first glance, is almost irre- 

 sistible to those who can appreciate its significance. 

 Let us briefly recapitulate the facts. , 



It has been proved that shooting-stars come from 

 8 



