ASTRONOMY. 155 



as composed of meteorites, or masses of meteotitic vapor pioduced by 

 lieat brought about l>y condeusatiou of meteor-swarms due to gravity, 

 so that the existing distinction between stars, comets, and nebul;e rests 

 on no physical basis. All alike are meteoritic in origin, the differences 

 between them depending upon differences in temperature, and upon the 

 closeness of the component meteorites to one another. Noihc (new stars 

 that blaze forth suddenly) are explained as produced by the clash of 

 meteor-streams, and most variable stars are regarded as uucondensed 

 meteor-streams. Stars with spectra like that of Alpha Orionis (Rigel) 

 are considered not as true suns, but as mere clouds of incandescent 

 stones ; probably the first stage of meteoritic condensation. Stars with 

 spectra of the first and second type represent the condensed swarm in 

 its hottest stages, while spectra of Secchi's fourth type indicate an ad- 

 vanced state of cooling." 



The general conclusions arrived at by Mr. Lockyer may be thus 

 summarized: All self-luminous bodies in space are composed of me- 

 teorites variously aggregated, and at various stages of temperature 

 depending upon the frequency and violence of their mutual collisions. 

 Comets, nebula?, bright-line stars, st^ars showing banded spectra of the 

 tliird type, including most long-period variables, are to be regarded as 

 veritable meteor-swarms; they are made up, that is to say, of an in- 

 definite multitude of separate and (in a sense) independent solid bodies, 

 bathed in evolved gases, and glowing with the heat due to their ar- 

 rested motions. "The existing distinction," we are told, "between 

 stars, comets, and nebula? rests on no physical basis." Stars, on the 

 other hand, of the Sirian and solar types (constituting the only true 

 "suns") are vaporized meteor-swarms; their high temperatures repre- 

 sent the surrendered velocities of myriads of jostling particle?, drawn 

 together by the victorious power of gravity. 



"Collisions" are not however exclusively relied upon for the cos- 

 mical production of light and heat. It is admitted that the luminosity 

 of comets and nebulre must be largely due to electrical excitement; 

 nor is any reason apparent why its influence should be restricted to 

 these two classes of bodies. Destruction of movement by impacts can 

 scarcely be made to supply its place. Occasional illuminative effects 

 may be derived from it, but none that are uniform and i)ermauent. 



The small bodies which, more or less plentifully distributed, appear 

 to pervade space, are in this theory treated as the fundamental atoms 

 of the universe. lint it is evident that we can not begin there. Tiiey 

 have a history, marked perhaps by strange vicissitudes. They may be 

 agents of regeneration, but they are almost certaiidy ])roducts of de- 

 struction. Possibly they are seed as well as dust, and serve as the 

 material link between the creation and decay of successive generations 

 of suns. 



The orhifs of meteorites. — Prof. IT. A. Newton, of Yale College, lias 

 carefully studied the evidence available for determining the "former 



