THE REALMS-OF SPACE, AND CONJECTURES REG 1RDING THAT WHICH 

 APPEARS TO OCCUPY THE SPACE INTERVENING BETWEEN THE 

 HEAVENLY BODIES. 



That portion of the physical description of the universe 

 which treats of what occupies the distant regions of the 

 heavens, filling the space between the globular cosmical 

 bodies, and is imperceptible to our organs, may not unaptly 

 be compared to the mythical commencement of ancient his- 

 tory. In infinity of space as well as in eternity of time, all 

 things are shrouded in an uncertain and frequently deceptive 

 twilight. The imagination is here doubly impelled to draw 

 from its own fullness, and to give outline and permanence to 

 4iese indefinite changing forms.* This observation will, I 

 trust, suffice to exonerate me from the reproach of confound- 

 ing that which has been reduced to mathematical certainty 

 by direct observation or measurement, with that which is 

 founded on very imperfect induction. Wild reveries belong 

 to the romance of physical astronomy ; yet the mind famil- 

 iar with scientific labors delights in dwelling on subjects 

 such as these, which, intimately connected with the present 

 condition of science, and with the hopes which it inspires, 

 have not been deemed unworthy of the earnest attention of 

 the most distinguished astronomers of our day. 



By the influence of gravitation, or general gravity, as well 

 as by light and radiating heat,f we are brought in contact, as 

 we may with great probability assume, not only with our own 

 Sun, but also with all the other luminous suns of the firma- 

 ment. The important discovery of the appreciable resist- 

 ance which a fluid filling the realms of space is capable of 

 opposing to a comet having a period of revolution of five 

 years, has been perfectly confirmed by the exact accordance 

 of numerical relations. Conclusions based upon analogies 

 may fill up a portion of the vast chasm which separates the 

 certain results of a mathematical natural philosophy from 

 conjectures verging on the extreme, and therefore obscure 

 and barren confines of all scientific development of mind. 



From the infinity of space — an infinity, however, doubted 



* Cosmos, vol. i., p. 87. (Compare the admirable observations of 

 Encke, Ueber die Anordnung des Sternsy stems, 1844, s. 7.) 

 t Cosmos, vol. i., p. 154, 155. 



