558 COSMOS. 



primitive forms of the loosely aggregating matter in space. 

 Under these presuppositions it becomes a question whether, 

 notwithstanding the enormous distance of the nearest fixed 

 stars, whose parallax we know from the aphelion of the Comet 

 of 1680, some of the comets which appear in the heavens may 

 not be merely wanderers through our solar system, moving 

 from one Sun to another ? 



Next in order to the group of comets, I shall speak of the 

 ring of the zodiacal light, as with great probability belonging 

 to our solar region, and after that of the swarms of meteoric 

 asteroids which sometimes fall upon our earth, and with 

 regard to whose existence, as bodies in space, by no means 

 unanimous opinions prevail. As in accordance with the 

 course adopted by Chladni, Olbers, Laplace, Arago, Sir 

 John Herschel, and Bessel, I consider the aerolites to be of 

 decidedly extra-terrestrial cosmical origin, I may venture, at 

 the conclusion of the section upon the planets, confidently 

 to express the expectation that, by continued accuracy in 

 the observation of aerolites, fire-balls, and shooting-stars, the 

 opposite opinion will disappear in the same way that the opi- 

 nion, universally diffused up to the sixteenth century, as to 

 the meteoric origin of the comets has long done. While these 

 bodies were considered by the astrological corporation of 

 " Chaldeans in Babylon," by the greater part of the Pytha- 

 gorean school, and by Apollonius Myndius, as cosmical bodies 

 reappearing at definite periods in long planetary orbits, the 

 powerful anti -Pythagorean school of Aristotle and that of 

 Epigenes, controverted by Seneca, declared the comets to be 

 productions of meteorological processes in our atmosphere.* 4 



made since the death of the great man, in the resolvaUUty of so 

 many nebulous spots into crowded heaps of stars ; the circum- 

 stance also that the comets have a portion of reflected pola- 

 rized light, which the self-luminous bodies are destitute of. 

 Compare Cosmos, vol. iii. pp. 192, 303. 315. 



** There were divisions of opinion at Babylon in the learned 



