230 On the Meteor of May 18th, 1838, 



o'clock in the evening where the meteor was vertical. The point 

 then towards which the earth's motion was directed, had passed 

 by nearly two hours the inferior meridian. The line of direction 

 was inclined to the horizon about 52°, and its azimuth was 

 somewhat east of north. The meteor's course was nearly north 

 and parallel with the horizon. Its velocity was thirty miles 

 per second ; that of the earth 19 miles. The directions of the 

 earth and meteor were inclined to each other about 64°, and the 

 meteor's velocity of thirty miles was its velocity relatively to the 

 earth. It is then simply a mathematical question to determine 

 what must have been the absolute direction and velocity of the 

 meteor's motion, in order that, combined with the earth's motion, 

 it may give the above resultant. The velocity I find to be about 

 forty miles per second. A part of this velocity, less however than 

 seven miles, was due to the earth's attraction. We must then 

 admit that a small collection of exceedingly rare matter, revolv- 

 ing about the sun in an orbit which at one point coincided nearly 

 with that of the earth, but moving with about double the velocity, 

 plunged into the earth's atmosphere, took fire, and exhibited the 

 splendid phenomenon of May 18. That no portion of this body" 

 escaped from the earth's atmosphere and continued its solitary 

 route, we cannot positively affirm ; although the appearances seem 

 to favor the supposition that the body was quite consumed in our 

 atmosphere. 



For the curvature of the meteor's path we can perhaps give 

 only a hypothetical explanation. When a ball is moving with 

 great velocity through the air, if one side be of such a form as to 

 experience greater resistance than the opposite, it will be rela- 

 tively retarded, and the path of the body will deviate towards 

 that side. Now as it is highly improbable that the opposite sides 

 of the meteor should be perfectly symmetrical, it might be ex- 

 pected to deviate more or less from a straight line. Moreover, 

 the progress of the meteor was marked by combustion, which 

 may be supposed to have been attended by a copious evolution of 

 gas. Now if this gas should be evolved upon one side of the me- 

 teor more abundantly than on the other, it would become a moving 

 force, which by reaction would cause the meteor to deviate to the 

 opposite side. As these two causes appear to me highly probable, 

 and adequate to account for the phenomenon, I think it superflu- 

 ous to search for others. The earth's attraction would hardly 

 produce the hundredth part of the deviation from a straight line 



