ORIGIN OF COMETS AND METEORS. 55 



stars, or rather of suns (we must now use the more general word), to 

 be added to those regarded by Daubree as the bodies from which me- 

 teorites (and meteors of all classes, according to Professor Newton's 

 just generalization) have proceeded. We may in one sense, indeed, 

 be said to have multiplied Daubree's sun-sources of meteors manifold, 

 since for every sun now existing in space our views as extended show 

 a whole family of sun-like orbs. But in reality we have only strength- 

 ened our theory by the addition of the suns which once belonged to 

 our present sun's domain, for these alone could in any way explain the 

 meteors and meteor-streams which had prevented us from accepting 

 stellar (or rather extra-planetary) origin for meteoric bodies. It is to 

 be observed, however, that these suns which we now introduce into the 

 theory were not all active at the same time. We must regard them as 

 distributed in time much as the stars are distributed in space some 

 very far off, others far off, indeed, but yet comparatively near ; and in 

 determining the distance of time at which they were active as suns, we 

 can not range them in any definite order according to their mass. 

 For instance, our own earth, though much more advanced in planetary 

 life that is, far cooler than a giant planet like Jupiter, was probably 

 in an actively sun-like state at a much more recent time : since the in- 

 terval of time during which Jupiter has been cooling from the sun-like 

 stage to his present fiery condition enormously exceeded, in all proba- 

 bility (owing to the vastness of his mass), the time occupied by the 

 earth in passing from the sun-like stage through the fiery stage to her 

 present cool and habitable condition ; and, on the other hand, though 

 Mars is much more advanced in planetary life than the earth, yet it is 

 quite possible (though we can form no definite opinion in this case as 

 in the former) that Mars might have been in the sun-like stage later 

 than the earth. 



We may observe here that we not only remove from Daubree's 

 theory, by this extension of it, the difficulties which had before pre- 

 vented vis from accepting it as a general theory of the origin of me- 

 teors, but we place the theories suggested by Tschermak, Meunier, 

 Schiaparelli, and others, in a much more satisfactory light than before. 

 It is properly objected to Tschermak's theory, by Professor Newton 

 and others, that our earth can not be supposed to have ever had while 

 a world explosive energy such as that theory imagines ; but when the 

 earth was in the sun-like state she could do all that might befit a sun. 

 We know that our sun can eject matter from his interior with veloci- 

 ties sufficing to carry such matter forever away from him, for he has 

 been caught, first by Professor Young in 1872, and several times since, 

 in the act. What our sun with his much vaster energies can do eject- 

 ively to overcome the withdrawing power of his own much mightier 

 mass, we may well believe that our earth in her sun-like days could do 

 to overcome the attraction of her smaller mass. The only difference 

 would be that while the sun on such occasions expels matter so as to 



