On the Meteors of 13th November, 1833. 163 



We have finally to enter on the inquiry, What relations did the 

 body which afforded the meteoric shower ; sustain to the earth ? Was 

 it of the nature of a satellite, or terrestrial comet, that revolves around 

 the earth as its center of motion — was it a collection of nebulous mat- 

 ter, which the earth encountered in its annual progress — or was it a 

 comet, which chanced at this time to be pursuing its path along with 

 the earth, around their common center of motion ? 



We conclude that it could not have been of the nature of a satel- 

 lite to the earth, because it remained so long stationary with respect 

 to the earth. The time in which a satellite, at the distance of 2238 

 miles from the surface, or 6194 miles from the center of the earth, 

 would complete its revolution, may be estimated as follows. The 



# 



i 



is given by the following formula,* T=2*r [3— j 2 , where * is the ra- 

 tio of the circumference of a circle to its diameter, r the radius of 

 the earth, and m the space through which a body falls at the surface 

 of the earth in 1". That is, 



m /3956X5280U 

 T=2x3.14159^ 1^2 j =84.3 minutes. 



By Kepler's Law, 3956 J : 6194 ::84.3 : 165.2'. 



That is, the periodical time of a satellite, revolving in a circle at 

 the distance of 6194 miles from the center of the earth, would be 

 two hours, forty -five minutes, and twelve seconds ; and consequently, 

 its mean motion at the perigee, in a circle, would be 3.926, or nearly 

 4 miles per second ; and its motion in an eccentric ellipse at the per- 

 igee, would be 5.552, or about 5^ miles per second. f This result 

 is plainly incompatible with the supposition that the body in question 

 was a satellite to the earth, since it remained stationary with respect 

 to the earth, according to Dr. Aiken, for at least two hours, — a pe- 

 riod sufficient to have carried it nearly round the earth in a circular 

 orbit, and through many degrees of a parabolic orbit. 



Nor can we suppose that the earth, in its annual progress, came 

 into the vicinity of a Nebula, which was either stationary, or wan- 

 dering lawless through space. Such a collection of matter could 

 not remain stationary within the solar system, in an insulated state ; 

 and had it been in motion in any other direction than that in which 

 the earth was moving, it would soon have been separated from the 



See Vince's Fluxions, Prop. xl. Ex. 6. t Gregory's Astion. Art. 536 



