STAR OR STAR-MIST. i 5I 



Lindsay's opinion, which is in any case a somewhat bold inference 

 from a single observation. Assuredly the discovery just made is in 

 direct opposition to a certain argument, derived from the gaseity of 

 nebulae, in favor of the gaseous hypothesis of Laplace an argument 

 which had always appeared to the present writer insufficiently estab- 

 lished. But the nebular hypothesis, regarded not merely in the form 

 suggested by Laplace (in which form it was utterly inconsistent with 

 physical facts now known), but in the wider sense which would simply 

 present our solar system in the remote past as in a nebular state, with- 

 out defining its nebulosity as due either to gaseity on the one hand, 

 or to a mixed meteoric and cometic constitution on the other, has 

 most certainly not received a shock, but rather receives strong sup- 

 port, from Mr. Copeland's observation. A theory of the evolution of 

 the solar system, advocated by me during the last seven years, accord- 

 ing to which the solar system had its origin in meteoric and cometic 

 aggregation, requires that during the long ages through which the 

 process of development continued there should be occasional outbursts 

 of light and heat in moderate degree from the rest of the system, even 

 to its outskirts. That intense heat imagined by Laplace as pervad- 

 ing the entire gaseous mass, extendiug originally far beyond the path 

 of the remotest planet of our system, would require, indeed (if it were 

 a physical possibility in other ways), that the spectrum of a develop- 

 ing solar system should be uniformly that of gaseity for millions on 

 millions of years. If it had been found or could be proved that the 

 gaseous nebulae are in a state of intense heat, Laplace's gaseous hy- 

 pothesis would have had one powerful argument in its favor. This 

 argument has been strongly urged by those who have taken that 

 special view of the gaseous nebulae which the recent discovery shows 

 to be erroneous. But those who have maintained, as I have, that in 

 the gaseous nebulae we probably " see vast systems of comets travel- 

 ing in extensive orbits around nuclear stars," will find confirmation, 

 not disproof, in the discovery lately made, especially when considered 

 in combination with the circumstance that Prof. Wright, of Yale, has 

 found the cometic spectrum to be emitted by meteoric masses exposed 

 to moderate heat; while, under slight changes of condition, the co- 

 metic spectrum of bright carbon bands appears to give place to the 

 nebular bright-line spectrum. 



However, speculation apart, we have in the discovery just made a 

 most important fact for our guidance the fact, namely, that a body 

 which to ordinary observation has been in all respects like the star in 

 the Crow T n, and even under spectroscopic observation shone for a 

 while with true stellar light, has dwindled into a nebula giving the 

 spectrum which has heretofore been regarded as indicative of ordinary 

 gaseity. English Mechanic. 



