378 ' Miscellanies. 



number of revolutions, while the earth makes one. But its peri- 

 odic time could not be a less aliquot part than one half a year; for 

 a less period, as one third, would, according to Kepler's law, make 

 the whole major axis of its orbit only about ninety one millions of 

 miles, — implying an orbit too small to permit the body ever to come 

 near to the earth- 

 As the periodic time cannot be less than half a year, neither can it 

 be greater; for then a conjunction could not take place at the same 

 part of the earth's orbit in two successive years. Hence, I inferred 

 that the periodic time is six months nearly. 



Such a time of revolution gives, for the major axis of its orbit 

 one hundred and nineteen millions of miles; and the orbit must evi- 

 dently be one of considerable eccentricity, since one part of it is 

 found reaching near to the earth, at a distance from the sun of about 

 ninety five millions of miles. Hence, it is inferred that the orbit is 

 an ellipse, the distances from the lower focus being respectively 

 ninety five and twenty four millions of miles. That the body is near 

 its aphelion at the time of the meteoric shower, (and consequently 

 that the aphelion distance is nearly equal to the distance of the earth 



from the sun,) was inferred from the fact that the earth and the me- 

 teoric body remained so long together, — a period of at least eight 

 hours ; for had the body been merely crossing the earth's orbit, or 

 had its direction been any other than nearly the same with the 

 earth's, the two bodies would sooner have separated. Nor would 

 such a shower of meteors have been equally probable at any other 

 point of conjunction, although, during the year, two other inferior 

 conjunctions actually occur ; for, the periodic time being as It is, no 

 other point of conjunction would take place, when the body was suf- 

 ficiently near to the earth. 



4. That only the " extreme portions" of the supposed nebulous 

 body descended to the earth, is indeed to some extent matter of con- 

 jecture ; but such an inference is rendered probable from the known 

 extent of astronomical bodies, and still more from the fact, that after 

 successive meteoric showers, the body was still able to afford so co- 

 pious a shower as occurred inlS33* 



5. I have thought it possible^ that the unexplained phenomenon 

 called the Zodiacal Lights is the very body in question, although 

 the existence of a nebulous body, affording the meteoric shower, was 

 inferred without the least reference to that light. But the follow- 

 ing ai-e remarkable facts. 



