AERULITKS. 1 il 



was on the Siberian coast of the Polar Sea, he observed, during 

 an Aurora BoreaHs, certain portions of the vault of heaven, 

 which were not illuminated, light up and continue luminous 

 whenever a shooting star passed over them. 



The different meteoric streams, each of which is composed 

 of myriads of small cosmical bodies, probably intersect our 

 Earth's orbit in the same manner as Biela's comet. Accord- 

 ing to this hypothesis, we may represent to ourselves these 

 asteroid-meteors as composing a closed ring or zone, within 

 which they all pursue one common orbit. The smaller plan- 

 ets between Mars and Jupiter present us, if we except Pallas, 

 with an analogous relation in their constantly intersecting 

 orbits. As yet, however, we have no certain knowledge as 

 to whether changes in the periods at which the stream be- 

 comes visible, or the retardatio7is of the phenomena of which 

 I hav^e already spoken, indicate a regular precession or oscilla.- 

 tion of the nodes — that is to say, of the points of intersection 

 of the Earth's orbit and of that of the ring ; or whether this 

 rinsf or zone attains so considerable a degree of breadth from 

 the irregular grouping and distances apart of the small bodies, 

 that it requires several days for the Earth to traverse it. The 

 system of Saturn's satellites shows us likewise a group of im- 

 mense width, composed of most intimately-connected cosmical 

 bodies. In this system, the orbit of the outermost (the seventh) 

 satellite has such a vast diameter, that the Earth, in her rev- 

 olution round the Sun, requires three days to traverse an ex- 

 tent of space equal to this diameter. If, therefore, in one of 

 these rings, which we regard as the orbit of a periodical 

 stream, the asteroids should be so irregularly distributed as to 

 consist of but few groups sufficiently dense to give rise to 

 these phenomena, we may easily understand why we so sel- 

 dom witness such glorious spectacles as those exhibited in the 

 November months of 1799 and 1833. The acute mind of 

 Olbers led him almost to predict that the next appearance 

 of the phenomenon of shooting stars and fire-balls intermixed, 

 falling like flakes of snow, would not recur until between the 

 12th and 14th of November, 1867. 



the 11th and 12tli of November, 1799, a similar fiery mauif'estalioii had 

 been observed in the heavens. But it was on the 21st of October, 1766, 

 and not in the beginning of November, that the earthquake occurred. 

 Possibly some traveler in Quito may yet be able to ascertain the day 

 on which the volcano of Cayambe, which is situated there, was for the 

 6j)ace of an hour enveloped in falling slars, so tlmt the inhabitants en- 

 deavored to appease heaven by religious processions. {Eelat. Hist., 

 I' \., ciiap. i\'., p .307 ; chap, x., j). .520 and 527.) 



