ON MATTER, FORCE, AND MOTION IN SPACE. 59 



exquisitely subtle material medium the occupant of 

 space throughout the universe. The unprofitable ques- 

 tions of ponderable and imponderable are put aside by 

 the conviction that such medium is necessary to the 

 existence of recognised phenomena. But of the inter- 

 planetary spaces, those with which we have most con- 

 cern, ether is not the sole occupant. Eecent observa- 

 tions, eveiy day augmenting upon us, show the presence 

 of matter in motion, under different forms of aggrega- 

 tion, in these interspaces ; subject doubtless to the 

 general laws which govern the planets and satellites, 

 but with special anomalies not yet fully explored. The 

 various phenomena of meteors, some of them seemingly 

 connected with rings of nebulous matter having peri- 

 odical revolutions round the sun comets, zodiacal 

 light, aerolites, &c. all attest the large presence of 

 matter in this ethereal domain ; the residue, it may be, 

 of those successive condensations from which we sup- 

 pose the different bodies of the solar system to have 

 derived their several forms and place in the heavens. 

 Such intervening material elements, we have much pre- 

 sent reason to believe, do not differ greatly from those 

 familiar to us on earth. But whatever their nature, 

 they doubtless have definite physical relations to the 

 medium in which they move. The phenomena of cer- 

 tain comets afford evidence of this, while at the same 

 time furnishing argument for the existence of the 

 medium itself. 



We have hitherto been regarding chiefly what may 

 be termed the ether of outer-space. Every difficulty 

 is augmented when we regard it in closer connexion 



